U.S. Robotics I-modem Command Reference U.S.
U.S. Robotics I-modem Command Reference The material contained in this manual is for information purposes only and is subject to change without notice. No part of this document may be reproduced, transmitted, transcribed, or stored in a retrieval system in any form or by any means, mechanical, magnetic, electronic, optical, chemical, or otherwise without the written permission of U.S. Robotics. U.S. Robotics and the U.S. Robotics logo are registered trademarks of U.S. Robotics. Courier, V.
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U.S. Robotics I-modem Command Reference Chapter 15 Troubleshooting Problems That Occur Before Connecting Problems that Occur After Connecting If You Still Have Problems 15-1 15-1 15-5 15-10 Chapter 16 Analog Synchronous Applications Requirements Dial Using V.
U.S. Robotics I-modem Command Reference Ampersand (&) Command Set Percent (%) Command Set Asterisk (*) Command Set S-registers A-12 A-24 A-28 A-32 Appendix B ASCII Chart B-1 Appendix C Fax Information for Programmers Fax Service Class 1 Commands FAX Service Class 2.
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U.S. Robotics I-modem Command Reference Chapter 1 Using the AT Command Set I-modems are controlled using AT commands. To send AT commands to the I-modem, connect a computer with an EIA-232 serial port to the I-modemÕs serial port. The computer must be running a communications software package. Before you can send any AT commands to your I-modem, you need to put your communications software in Terminal mode. In Terminal mode, what you type is sent directly to the I-modem.
U.S. Robotics I-modem Command Reference ¥ You can leave zeros off commands because a missing numeric parameter is assumed to be a zero. For example, ATE is equivalent to ATE0 . ¥ You can create compound commands of up to 60 characters between AT and . Spaces donÕt add to the count, but hyphens and parentheses do. HereÕs an example: AT&K3X2DT5551234 AT Attention; a command follows. &K3 Disable MNP5 data compression; use only V.42bis compression.
U.S. Robotics I-modem Command Reference A> Repeat the last-issued command until canceled by pressing any key. Do not type AT or press Enter. AT Attention preÞx: Informs the I-modem that a command is coming. AT must precede all commands except A/, A>, and +++. S-registers S-registers are addresses of places in memory where various timing parameters, redeÞnitions of selected ASCII characters, and other conÞguration settings are stored.
U.S. Robotics I-modem Command Reference Displaying S-register Settings All S-registers To display the S-register settings in the NVRAM templates, issue the command: ATI5 To display the S-register settings in RAM (the current conÞguration), issue the command: ATI4 In both cases, S-register settings appear as a table seven columns wide, each entry of the form, "Smm=nnn" where mm is a register number between 0 and 67 and nnn is a decimal value between 0 and 255.
U.S. Robotics I-modem Command Reference Setting an S-register To change a setting for an S-register in the current conÞguration, use the command ATSr=n where r is the register's number and n is a decimal value from 0-255 (unless otherwise indicated) that speciÞes the setting. Important If you do not follow an S-register setting with &W, the setting will be retained only until the next reset or power-off.
U.S. Robotics I-modem Command Reference Bit-Mapped S-registers Understanding Bit-Mapped S-registers Certain registers are "bit-mapped." A bit-mapped register uses one number to describe a collection of settings. While bit-mapping allows us to pack a lot of information in a small space, it is complex. Unfortunately, some discussion of binary mathematics is necessary to explain bit-mapping. When the I-modem displays the value of an S-register, you see a decimal value between 0 and 255.
U.S. Robotics I-modem Command Reference Each bit can also be assigned a value corresponding to its number: Bit Value 7 27 = 128 6 26 = 64 5 25 = 32 4 24 = 16 3 23 = 8 2 22 = 4 1 21 = 2 0 20 = 1 Converting Bits to Decimal Values Starting with a string of 8 bits, assign each Ò1Ó bit a value based on its position. Add the values to come up with the Þnal decimal value.
U.S. Robotics I-modem Command Reference HereÕs an example of how bits are converted to decimal values: 01001111 0 1 0 0 1 1 1 1 0 + 64 +0 +0 +8 +4 +2 +1 = 79 Converting Decimal Values to Bits Convert decimal values to bits by Þnding the largest decimal equivalent that is less than the decimal value. Subtract the decimal equivalent and mark the equivalent bit Ò1.Ó Continue until the decimal value is zero.
U.S. Robotics I-modem Command Reference Setting Bit-Mapped S-registers You can set bit-mapped S-registers using either bits or decimal values. While it may be simpler for you to set the bits individually, I-modems display the S-register settings in decimal form. Using Bits Turning individual bits on and off is the more direct way to set bit-mapped S-registers. To do this, specify the S-register that you want to set, and then indicate which bits you want to turn on (1) or off (0). For example, ATS13 .0=1 .
U.S. Robotics I-modem Command Reference Getting a List of S-registers To display a list of S-registers, issue the following command while in Terminal mode: ATS$ Also, the command ATI5 displays the values of the S-registers as part of the listing of NVRAM's contents. More command lists are available. (See Chapter 13, Displaying Help Screens.
U.S. Robotics I-modem Command Reference Chapter 2 Modes of Operation Command and Online Modes Command mode. When the I-modem is in Command mode, you can control it using AT commands. Online mode. When the I-modem is in Online mode, it is connected over telephone lines with another device. Online Command mode. By entering Online command mode, you can send the I-modem commands while you are online with another device. Entering Online Command Mode +++ Revert to Command mode.
U.S. Robotics I-modem Command Reference Depending on how bit 0 of S-register 14 is set, the I-modem will either revert to Command mode or hang up when you send the escape code. To be able to change operating modes without losing connections, make sure bit 0 of S-register 14 is OFF: ATS14.0=0&W Table 2.1.
U.S. Robotics I-modem Command Reference You can change the characters used to revert to Command mode or change the wait time by resetting Register S2 or S12. See the S-register Summary in Appendix A, Alphabetic Command Summary. Returning to Online Mode On Changes from Command mode to Online mode. ATO There are two ways to return online. O0 Return online. O1 Return online and retrain. You might use ATO1 to resynchronize if you experienced errors during a non-ARQ data transfer.
U.S. Robotics I-modem Command Reference your screen. The Online-mode local echo setting determines whether the data that the I-modem transmits to another device appears on your screen. Command-Mode Local Echo En Enable or suppress Command-mode local echo. E0 Command mode echo OFF. Your typed commands do not appear on your screen. E1 Command mode echo ON. Your typed commands appear on your screen. Online-Mode Local Echo Fn Enable or suppress Online mode local echo.
U.S. Robotics I-modem Command Reference F1 Online echo OFF. (Sometimes called full duplex.) Data and Fax Modes Once you have started in Command mode, you can initialize the I-modem in Data or Fax mode. Data mode. In Data mode, the I-modem is prepared to make calls to and receive calls from digital and analog devices, such as terminal adapters and modems. Fax mode. In Fax mode, the I-modem is prepared to make calls to and receive calls from analog facsimile devices, such as fax modems and fax machines.
U.S. Robotics I-modem Command Reference You can always switch the operating mode manually using one of these commands: AT+FCLASS=0 (Switch to Data mode) AT+FCLASS=1 (Switch to Class 1 Fax mode) AT+FCLASS=2.0 (Switch to Class 2.0 Fax mode) If you are not sure whether the I-modem is in Data or Fax mode, type the following command: AT+FCLASS? The I-modem returns a value of 0 to indicate Data mode, 1 to indicate Class 1 Fax mode, or 2.0 to indicate Class 2.0 Fax mode.
U.S. Robotics I-modem Command Reference Chapter 3 Dialing, Answering, and Hanging Up I-modems always make and receive calls over ISDN lines. Everyday actions, such as dialing and answering, are done differently over ISDN than they are over analog lines. For instance, analog dialing is done by sending tones or pulses over the line. ISDN devices dial by sending digital signals over the line. Also, your analog phone rings because it receives a burst of voltage through the line.
U.S. Robotics I-modem Command Reference Dial Options T Tone dial. This option is ignored because it is not necessary for ISDN dialing, but it is accepted for compatibility with todayÕs communication software packages. P Pulse dial. Accepted but ignored. , (Comma) Pause for the length of time speciÞed by S-Register 8. The default is 2 seconds. / (Slash) Pause for 125 milliseconds. W Wait for a second dial tone before continuing to dial.
U.S. Robotics I-modem Command Reference I-modem to detect at least one ring, wait for 5 seconds of silence at the other end of the call, and then continue. To use the @ command, set an I-modem to X3, X4, or X7. If it is set to X2 or lower, the I-modem will return an ERROR message when it encounters the @ character. If itÕs set to X5 or X6, the I-modem hangs up when it detects a voice answer. ; (Semicolon) Return to Command mode after dialing.
U.S. Robotics I-modem Command Reference L Dial the last-dialed number. Start a command with ATDL instead of using A/ if you wish to send an I-modem non-Dial commands before dialing again. L? Display the last-dialed number. Sn Dial the number stored in NVRAM at position n, where n = 0*9. See Chapter 4, Working with Memory, for instructions about saving phone numbers to memory. In addition to the digits 0 through 9, I-modems also accept * and #. Canceling Dialing Any key Stop dialing or stop repeating.
U.S. Robotics I-modem Command Reference Repeating a Command > Dial a number, wait 60 seconds for a connection, and then hang up. Wait 2 seconds, then redial. Make a maximum of 10 attempts. For example, if you know that the device you are calling is frequently busy, include the Repeat command: AT>DT1234567 or ATDT1234567> To stop the repeating, press any key during the pause between dial attempts.
U.S. Robotics I-modem Command Reference Auto Answer You can set an I-modem to receive calls unattended. Load your communications software as you normally do, and set the I-modem to Auto Answer. Also, set your communications software to save incoming messages and/or Þles. To enable Auto Answer, send the following command (this example instructs an I-modem to pick up on the Þrst ring): ATS0=1 Note You can substitute a higher value.
U.S. Robotics I-modem Command Reference Note If S0=0, Auto Answer will be disabled. Send ATI4 and be sure that S0=1*255. Disabling Auto Answer To disable Auto Answer, set an I-modem to answer on zero rings with the following command: ATS0=0 Hanging Up To end a connection with a remote device, type the following: (wait 1 sec) +++ (wait 1 sec) ATH0 Making International Calls Two commands apply to analog international calls above 1200 bps: Bn and &Gn. Bn Handshake options.
U.S. Robotics I-modem Command Reference &Gn B0 ITU-T (formerly CCITT) answer sequence. Default. This is required to answer all V.34-type calls, as well as calls from overseas. B1 Bell answer tone. This setting selects HST modulation, but should only be used if an I-modem is not required to answer V.34-type calls. This setting applies only to analog overseas calls at 2400 or 1200 bps. British phone switching systems require devices to send an 1800 Hz guard tone after they send an answer tone.
U.S. Robotics I-modem Command Reference Call Detection I-modems support Call Detection, which allows them to recognize whether an incoming call is analog data, Fax Class 1, or Fax Class 2.0. It is especially useful for BBSs because it automates recognition of different calls from multiple users. Call Detection is an optional Service Class 2.0 feature and is also implemented by U.S. Robotics for Fax Class 1 applications. To obtain a copy of the technical speciÞcation of U.S.
U.S. Robotics I-modem Command Reference Chapter 4 Working with Memory I-modems contain three types of memory that you can interact with: random access memory (RAM), nonvolatile random access memory (NVRAM), and Flash memory. RAM RAM holds the settings that apply to the current conÞguration. Any changes you make are active until you reset the I-modem or power it off. NVRAM NVRAM is user-conÞgurable. You can store, retrieve, and change settings in NVRAM. Loss of power will not affect your settings.
U.S. Robotics I-modem Command Reference What is Stored Where? Current Settings Current settings are saved in working memory (RAM). Any settings you change and do not save to the I-modem are active until you reset the I-modem or power it off. View current settings by sending ATI4. Saved Settings Settings you save to the I-modem are stored in NVRAM. View saved settings by sending ATI5. Permanent Settings Three templates of permanent settings are stored in Flash memory.
U.S. Robotics I-modem Command Reference Working with NVRAM If you want the new setting to be a default, write it to NVRAM at the same time, as in the following example (X6 is substituted for the Xn value stored earlier; any other setting that was changed can be saved to NVRAM): ATX6&W Note When writing a different default conÞguration to NVRAM, insert any additions after the &Fn command, but before &W. Otherwise, they will be overwritten by &Fn.
U.S. Robotics I-modem Command Reference To dial the phone number you saved, type: ATDS2 If the call requires a special setting, insert it in the command before the DSn command. In this example, &M0 (no error control) comes before DS2. AT&M0DS2 Note The &Zn=s command functions differently when Dial Security is enabled. (See Chapter 9, Dial Security, for more information.
U.S. Robotics I-modem Command Reference Many of the DIP switches that were present on Courier V.34 modems are under software control in the I-modem. These are the default settings: Table 4-1. Former DIP Switches Ð Default Settings Former DIPSwitch Number I-modem Default 1 &D2 DTR normal 2 V1 Verbal result codes 3 Q0 Display result codes 4 E1 Echo off-line commands (command mode local echo) 5 S0=1 Auto answer on ring 6 &C1 Normal carrier detect (CD) 7 S14.1=1 Result codes orig.
U.S. Robotics I-modem Command Reference Important Resetting the I-modem or powering it off and then on will not change these ÒDIP switchÓ settings! The only way to change them is to issue the commands manually. Save a setting change by following a command with &W.
U.S. Robotics I-modem Command Reference Last-Dialed Number (DL?) At this command, the I-modem sends the number stored in the last-dialed number buffer: ATDL? Table 4-2.
U.S. Robotics I-modem Command Reference Table 4-2.
U.S. Robotics I-modem Command Reference Table 4-2.
U.S. Robotics I-modem Command Reference Working with Flash Memory The I-modem permanently stores three conÞguration Òtemplates,Ó or prepared sets of commands, in Flash memory. You can retrieve a template and load it into current memory using the &Fn command. &Fn Load one of the three conÞguration templates from Flash memory into current memory. &F0 No ßow control (low performance). &F1 Hardware ßow control. &F2 Software ßow control.
U.S. Robotics I-modem Command Reference For more information about hardware and software ßow control, see Chapter 10, Flow Control. Table 4-3.
U.S. Robotics I-modem Command Reference Table 4-3.
U.S. Robotics I-modem Command Reference Table 4-3. &F1 Hardware Flow Control Template NVRAM Options Setting Description DTE rate* (Kbps) 19.2 _ * Detected by each I-modem from the AT preÞx of the &W com-mand that writes your defaults to NVRAM. Set your software to the desired word length, parity, and serial port rate defaults before sending the modem the AT É&W string. Table 4-4.
U.S. Robotics I-modem Command Reference Table 4-4. &F2 Software Flow Control Template NVRAM Options Setting Description Result code subset X7 Extended. Includes all codes except VOICE Protocol response codes &A3 Full protocol codes Serial port rate select &B1 Serial port rate Þxed higher than connect rate Guard tone &G0 U.S.
U.S. Robotics I-modem Command Reference Table 4-4. &F2 Software Flow Control Template NVRAM Options Setting Description Stored telephone number &Z0*9=0 Blank Externals only: V.25bis clock speed %N6 9600 bps Call type *V=0 Auto-detect the call type Word length* 8 Parity* 0 None DTE rate* (Kbps) 19.2 _ * Detected by each I-modem from the AT preÞx of the &W com-mand that writes your defaults to NVRAM.
U.S. Robotics I-modem Command Reference Table 4-5. &F0 No Flow Control Template NVRAM Options Setting Description Speaker control M1 ON during dial through connect Result codes Q0 Enabled Verbal or numeric result codes V1 Verbal result codes Result code subset X1 Basic Protocol response codes &A3 Full protocol codes Serial port rate select &B1 Serial port rate Þxed higher than connect rate Guard tone &G0 U.S.
U.S. Robotics I-modem Command Reference Table 4-5. &F0 No Flow Control Template NVRAM Options Setting Description Remote Digital Loopback (RDL) &T5 Deny RDL Break handling &Y1 Clear buffer, send immediately Stored telephone number &Z0*9=0 Blank Externals only: V.
U.S. Robotics I-modem Command Reference Note DIP switch settings override AT commands at power-on. Make sure DIP Switch 1 is ON, or the &F0 template will be loaded! Default Settings If DIP switch 1 is OFF at power-on, the &F0 settings are loaded instead. By default, the Þrst time the I-modem is turned on, it loads the settings stored in NVRAM, which are the same as the settings in the &F1 template.
U.S. Robotics I-modem Command Reference &W To substitute a template other than &F1, write the desired template to NVRAM using the &W command. AT&F2&W To modify the &Fn conÞguration in NVRAM, type your changes afterward and then save them to NVRAM, as in the following example (the original factory template remains intact): ATS10=40&A2&W Resetting I-modems Z or Z! Resets and loads the NVRAM settings when DIP switch 1 is ON (factory setting).
U.S. Robotics I-modem Command Reference Chapter 5 Controlling Result Code Displays This section explains how to control the display of result codes. ÒResult codeÓ is just another way of saying Òstatus message.Ó Result Code Display Commands The four commands listed below control whether result codes are displayed, and in what format they are displayed. Table 5-1. AT Commands That Control Result Code Diplay Command Effect Qn Enables or suppresses the display of result codes.
U.S. Robotics I-modem Command Reference Qn Vn Xn Enable/suppress the display of result codes. Q0 Display result codes. Q1 Do not display result codes. Q2 Do not display result codes while in Answer mode (see Chapter 2, Modes of Operation, for a description of modes). Display result codes in verbal or numeric form. V0 Display result codes in numeric form. V1 Display result codes in verbal form. Display one of the following sets of result codes. Default = X7 (see Tables 5-2 and 5-3).
U.S. Robotics I-modem Command Reference Table 5-2.
U.S. Robotics I-modem Command Reference Table 5-2.
U.S. Robotics I-modem Command Reference Table 5-3. Result Code Meanings Result Code Meaning 0/OK Command has been executed. 1/CONNECT Connection with another device. 2/RING Incoming ring detected. 3/NO CARRIER Carrier Detect has failed, or carrier has been dropped due to disconnect. 4/ERROR Command is invalid. 5/CONNECT 1200 Connection at reported rate.
U.S. Robotics I-modem Command Reference Table 5-3. Result Code Meanings Result Code Meaning Wait for Another The I-modem continues dialing as soon as it detects Dial Tone (W) another dial tone. See the dial options earlier in this chapter. Wait for an Answer(@) The I-modem continues dialing when it detects 5 seconds of silence on the line. (See the dial options earlier in this chapter.
U.S. Robotics I-modem Command Reference If the I-modem is set to X0 and the connection rate is 1200 bps-64 Kbps, result code 14 is displayed. The other result codes indicate connection rates and require a setting of X1 or higher.
U.S. Robotics I-modem Command Reference Note If your software cannot handle the added modulation information, select &A1 or &A0.
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U.S. Robotics I-modem Command Reference &A3 Default. Display error control (LAPM, HST, MNP, SYNC, V120, or NONE) and data- compression type (V42BIS, MNP5) indicators. In the following example, the devices negotiated error control for the call (ARQ), used V.34 modulation, are using the LAPM error-control protocol, and are using V.42bis compression. CONNECT 28800/ARQ/V34/LAPM/V42BIS Note The numeric identiÞers for &A3 result codes are the same as those used for &A2.
U.S. Robotics I-modem Command Reference Chapter 6 Controlling EIA-232 Signaling The EIA-2321 interface deals with the signals and voltages used when data is exchanged between a computer and a serial device, such as a modem or serial printer. While external I-modems have physical serial ports, internal I-modems have virtual serial ports. Even though you canÕt see the internal I-modemÕs serial port, the commands described in this chapter affect its internal serial communications.
U.S. Robotics I-modem Command Reference &Dn Tell the I-modem how to deal with the DTR signal. &D0 Operate as though the DTR signal is always ON. &D1 Use a change in the DTR signal to enter Command mode. Most communications software packages have a method for toggling DTRÑrefer to your softwareÕs manual for details. &D1 functions similarly to the escape code (+++). Return online with the On command, or hang up with the ATH command. &D2 Respond normally to the DTR signal.
U.S. Robotics I-modem Command Reference Do not change the default setting of &S0 unless you know that your installation requires a different setting. Few communications programs, if any, will require the I-modem to control DSR (&S1). &Sn Control how the I-modem sends the DSR signal. &S0 Send the DSR signal at all times. Default. &S1 When originating a call, send the DSR signal after dialing when the I-modem detects the remote analog deviceÕs answer tone.
U.S. Robotics I-modem Command Reference To change the DSR pulse time (in 20-second increments), set S-register 24. (See Appendix A, Alphabetic Command Summary.) Carrier Detect Carrier is another way of saying Òready signal from the device on the other end of the connection.Ó Under normal conditions, the I-modem sends a Carrier Detect (CD) signal in response to receiving the carrier from the device on the other end. &Cn Control how the I-modem sends the CD signal. &C0 CD always ON.
U.S. Robotics I-modem Command Reference Chapter 7 Controlling Data Rates You can set the I-modem to use Þxed or variable serial port rates and Þxed or variable connection rates. Serial port rates pertain to data transferred between your computer and the I-modem. Connection rates pertain to data transferred between the I-modem and the device at the other end of a connection. Serial Port Rates Set a Þxed serial port rate to get the highest possible throughput and the best performance.
U.S. Robotics I-modem Command Reference &Bn Set the serial port rate as variable or Þxed. &B0 Variable rates. Allows the I-modem to change its serial port rate to match the connection rate. &B1 Fixed rate. The I-modem always communicates with an attached device at the rate at which you have set the terminal or software, regardless of the connection rate. For the greatest throughput, set the serial port to 115200, 57600, or 38400 bps for high-speed calls, and to at least 9600 bps for 2400-bps calls.
U.S. Robotics I-modem Command Reference To implement this feature, Þrst set your software to the desired rate. Then send the AT&B2&W command. I-modems store the rate of the command in NVRAM along with the settings. The I-modem checks NVRAM for the speciÞed serial port rate each time it makes an ARQ connection. When sending subsequent conÞgurations to NVRAM, be sure your software is set to your selected serial port rate so the correct rate is maintained.
U.S. Robotics I-modem Command Reference &N0 Variable rates. Negotiate for the highest possible rate. &N1-&N16 Fixed rate. Connect only if the remote device is operating at the rate you specify. &N1 300 bps &N9 16.8 Kbps &N2 1200 bps &N10 19.2 Kbps &N3 2400 bps &N11 21.6 Kbps &N4 4800 bps &N12 24.0 Kbps &N5 7200 bps &N13 26.4 Kbps &N6 9600 bps &N14 28.8 Kbps &N7 12.0 Kbps &N15 31.2 Kbps &N8 14.4 Kbps &N16 33.
U.S. Robotics I-modem Command Reference Chapter 8 Remote Access You can set up the I-modem so other devices can view or change its conÞguration remotely. This feature might be helpful if you have problems connecting with another device: you could grant the other deviceÕs administrator access to your I-modem to check or correct its conÞguration. As the administrator of a multiport I-modem, you might use remote access if you are away from your multiport I-modem and want to make changes to its conÞguration.
U.S. Robotics I-modem Command Reference Setting Up Remote Access At the Host I-modem 1. Prepare to send AT commands. See Chapter 1, Using the AT Command Set, for details. 2. Enable remote access. Set Register S41 for a value of 1 or greater. S41 sets the number of log-in attempts available to the remote user. A setting of zero allows no log-in attempts, disabling remote access. ATS41=1&W Note This method will not work if the multiport I-modem is attached to certain synchronous devices.
U.S. Robotics I-modem Command Reference View-Only Only allows guest users to view the I-modemÕs conÞguration. View-and-Change Allows guest users to view and change the I-modemÕs conÞguration. Remote-access passwords can be up to eight alphanumeric characters long, and are not case-sensitive. %Pn Assign a remote-access password. %P0 Assign a view-only password. AT%P0=password %P1 Assign a view-and-change password.
U.S. Robotics I-modem Command Reference Erasing a Remote-Access Password To erase a remote-access password, type: AT%P0= or AT%P1= Warning Keep in mind that if you erase the %P1 password without disabling remote access (using ATS41=0), anyone could access the I-modem and change its conÞguration.
U.S. Robotics I-modem Command Reference 1. Be sure that the host device has enabled remote access and is set to auto-answer (ATS0=1). Know the password, if you will need one. 2. Call the host device (although it doesnÕt matter which device originates the call). 3. After a connection is established, do this: a. Pause 4 seconds. b. Type 4 tildes: ~~~~ c. Pause 4 seconds.
U.S. Robotics I-modem Command Reference nection. When the host accepts the password, the following message and prompt will appear on your screen: Remote Access granted Remote-> Note You may not be prompted for a password. If you arenÕt, password security is not active. The following prompt appears on your screen after you type the four tildes: Remote Access granted (query only), and then Remote->. 5. Continue with Viewing and Changing the HostÕs ConÞguration, later in this chapter.
U.S. Robotics I-modem Command Reference Quitting a Remote-Access Session If you want to quit the remote-access login before you have entered the password, return online by pressing C or typing ATO. After youÕve entered the password, you can quit by sending one of these commands: ¥ ATO ends the remote-access session and keeps the connection. ¥ ATH ends the remote-access session and ends the connection. ¥ ATZ ends the remote-access session, ends the connection, and resets the guest modem.
U.S. Robotics I-modem Command Reference Table 8-1. Access Privileges Note Access Privileges What You Can Do View-Only Use any of the inquiry (ATI) commands. View and ConÞgure Use any of the I-modem commands, except those that cannot be used while online (for example, ATD or ATA). You can also use remote conÞguration commands.
U.S. Robotics I-modem Command Reference %B2 600 bps %B8 38400 bps %B3 1200 bps %B9 57600 bps %B4 2400 bps %B10 115200 bps %B5 4800 bps %Fn Change data format. %Cn %F0 No parity, 8 data bits. %F1 Mark parity, 7 data bits. %F2 Odd parity, 7 data bits. %F3 Even parity, 7 data bits. Control whether and when to apply changes to the conÞguration. %C0 Defer changes. Default.
U.S. Robotics I-modem Command Reference Note Even though, by default (%C0), the changes you make do not take effect until the next connection, the new conÞgu-ration is reßected immediately in inquiry responses (ATIn). %C1 Note Restore the original conÞguration. Use this command to cancel any changes made during remote access and restore the original conÞguration.
U.S. Robotics I-modem Command Reference Quitting a Remote-Access Session If you want to quit the remote-access login before you have entered the password, return online by pressing C or typing ATO. After youÕve entered the password, you can quit by sending one of these commands: ¥ ATO ends the remote-access session and keeps the connection. ¥ ATH ends the remote-access session and ends the connection. ¥ ATZ ends the remote-access session, ends the connection, and resets the guest device.
U.S. Robotics I-modem Command Reference Chapter 9 Dial Security Dial Security is designed to protect networks and data centers from unauthorized access. A few terms need to be explained before we go any further: Local The device that is directly connected to the computer you are using. Remote The device at the other end of a telephone connection. Host The I-modem that receives calls from other devices and provides Dial Security. Guest The device that accesses the host.
U.S. Robotics I-modem Command Reference ¥ Autopass ¥ Password Prompting Setting Up Dial Security Here is a summary of the steps for setting up Dial Security: ¥ Set up an account for yourself. ¥ Identify your account as the Administrative Account. ¥ Set up guest-user accounts. ¥ Enable local (host) security. ¥ Choose a Dial Security method. ¥ Enable Dial Security. ¥ Activate the Dial Security settings.
U.S. Robotics I-modem Command Reference 1. Set up an account for yourself. Use any of the 10 available accounts (numbered 0Ð9) for your account. Use the %An command to set up user accounts. Figure 9-1 shows the Þve Þelds to concern yourself with. Note The %An command is automatically written to NVRAM. It does not require you to send &W.
U.S. Robotics I-modem Command Reference Dialback at a SpeciÞed Number To make the host I-modem hang up and then dial back a guest device at a speciÞed number, type: AT%A0=nanook,y,y,n,17085555555 To enable Dialback, you must enable Dial Security with Prompting in step 6.
U.S. Robotics I-modem Command Reference Warning Do not insert spaces between commas or between Þelds and commas. Spaces will invalidate the command. 2. Identify your account as the Administrative Account. Identify your account as the Administrative Account using the %L command. AT%L=PW0 This example sets account 0 as the Administrative Account. Once you set the administrative password, you cannot view or modify the guest account proÞles unless you enter the correct administrative password.
U.S. Robotics I-modem Command Reference 3. Set up guest-user accounts. Use the %An command to set up guest-user accounts in the same way you set up your administrative account. You can set up nine guest accounts (see Figure 9-2). AT%A0=password,y,y,n,5551000 SpeciÞed dialback number (up to 37 ASCII characters) Prompt user for dialback number? (y/n) Dialback enabled? (y/n) Account enabled? (y/n) Password. 8 characters maximum, case sensitive Account number (0-9) %A command Figure 9-2.
U.S. Robotics I-modem Command Reference Modifying Accounts After you have set up an account, you can modify each Þeld independently. If a Þeld is to remain as is, just insert a comma, as shown in the following command: AT%A1=,,,Y, The command above allows the guest user to supply a dialback number that is different from the one stored in the original account record. 4. Enable Local Security.
U.S. Robotics I-modem Command Reference Autopass Autopass is the default form of password protection. Autopass automates the process of logging in to the host modem, but it requires close cooperation between the guest and host devices. Using Autopass requires that: ¥ Both the host and guest devices are made by U.S. Robotics and have Dial Security enabled. ¥ The connection between the I-modems or modems is under V.42 error control (that is, both modems must be set to &M4 or &M5). Note Since V.
U.S. Robotics I-modem Command Reference ¥ If the guest did not enable Dial Security, the host will not accept the call unless prompting is enabled on the host I-modem. ¥ If the guest includes a valid password, the host permits a secure connection. Password Prompting While the use of Autopass is restricted to U.S. Robotics devices with Dial Security, Password Prompting allows connections with any guest device, as long as the guest user knows the correct password.
U.S. Robotics I-modem Command Reference Note There is no Password Prompting capability in analog synchronous mode. Password Prompting is more ßexible than Autopass because: ¥ Password Prompting doesn't require guest devices to support U.S. Robotics Dial Security. ¥ Password Prompting doesn't require a V.42 error-control connection. 6. Enable Dial Security. Warning Before you enable Dial Security, you must set up an administrative account and password. See Steps 1 & 2.
U.S. Robotics I-modem Command Reference Note You must use the &W command to save the settings in NVRAM. If you donÕt, the next time you reset or power off the I-modem, Dial Security will be disabled. ati10 USRobotics Courier I-modem with ISDN/V.34 DIAL SECURITY STATUS DIAL SECURITY ENABLED:[N]S53.0=1 LOCAL SECURITY ENABLED:[N]S53.2=1 PROMPTING ENABLED:[N]S53.1=1 FORCED AUTOPASS:[N]S53.
U.S. Robotics I-modem Command Reference OK Figure 9-1. The ATI10 Screen. Bold Characters Indicate the Commands Used to Control the Adjacent Fields 7. Send ATZ or ATZ! to activate the Dial Security settings! Note Make sure that DIP switch 1 is ON, which tells the I-modem to load the settings stored in NVRAM. If DIP switch 1 is OFF, the settings in ROM (&F0) are loaded, disabling Dial Security.
U.S. Robotics I-modem Command Reference Accessing Account Information (%S) Once Dial Security is enabled, you can access accounts by entering the local access password using the %S= command, which allows access to the accounts by disabling local security. AT%S=administrative password Note The device echoes the administrative password, which is case-sensitive. I-modems will accept an invalid password entry, but will lock out users from the security commands.
U.S. Robotics I-modem Command Reference Erasing Account Information (%E) Use the %E=n command to make system edits. %E=1 Erase local-access password. %E=2 Erase Autopass password. %E=3 Erase passwords in accounts 0Ð9. %E=4 Erase phone numbers in accounts 0*9. %E=5 Disable Account, Dialback, and New Number Þelds in accounts 0*9. To edit or overwrite an individual account or an individual account Þeld, use the %An= command described in Setting Up Dial Security earlier in this chapter.
U.S. Robotics I-modem Command Reference What the Guest User Needs to Do When guest users want to call in to the host (assuming you have enabled Dial Security by entering ATS53.0=1), ¥ They must know the password. ¥ If you have enabled Dialback, they must set their device to auto-answer. 1. If the host has security enabled, get a password from the hostÕs administrator. The password is case-sensitive, so be sure to copy it correctly.
U.S. Robotics I-modem Command Reference c. Check to see that you've set your Autopass password correctly by typing the following command: ATI10 Your Autopass password appears beside AUTOPASS PASSWORD. d. Once the Autopass password is set, enable your CourierÕs Dial Security by sending the following command: ATS53.0=1&W 3. If Dialback is enabled at the host I-modemÕs site, set your modem to answer the host I-modem when it dials back.
U.S. Robotics I-modem Command Reference ConÞguring Dial Security Remotely The host administrator can conÞgure the hostÕs security settings remotely. Note At the host device, you must have previously enabled remote access and assigned a remote-access password that allows view-and-change privileges (see Chapter 8, Remote Access). You may want to use your administrative password as your remote-access password. Dialing In From the Remote Site 1. From the remote site, connect to the host using Dial Security.
U.S. Robotics I-modem Command Reference 4. To end the remote session and reactivate Dial Security on the host, reset the guest device by typing: ATZ Warning If you do not use the ATZ command to end a remote-access session, Dial Security will remain disabled at the host, and anyone dialing in to the host for remote access will have access to the I10 screen and all Dial Security accounts.
U.S. Robotics I-modem Command Reference Chapter 10 Flow Control The I-modem has two buffers, one for data transmitted from your computer, and one for data received from the phone line. Buffers are data-storage areas of variable size. Flow control provides a system for stopping and starting transmission depending on how full the buffers are. Its goal is to prevent overÞlling the buffers and losing data. There are two kinds of ßow control: hardware and software.
U.S. Robotics I-modem Command Reference Hardware and Software Flow Control Hardware Flow Control I-modems implement hardware ßow control by detecting that a buffer is 90% full and then interrupting the Clear to Send (CTS) signal to stop the ßow of data. When the buffer is 50% full, the I-modem sends CTS to restart the ßow of data.
U.S. Robotics I-modem Command Reference If you use software ßow control and are transferring non-text (binary) Þles or using an XMODEM-type protocol, disable ßow control entirely using the &R1 and &I0 commands described in this section. In addition, set the serial port and connection rates equal using the &B0 and &N0 commands described in Chapter 7, Controlling Data Rates. The start command is called XON (for transmit on) and the stop command is called XOFF (transmit off).
U.S. Robotics I-modem Command Reference &In &R0 After sending the Request to Send (RTS) signal, pause before sending CTS. The delay is required by some synchronous mainframes and does not apply to asynchronous calls. &R1 Ignore the RTS signal. &R1 is required if your computer or software does not support RTS. &R2 Default. Hardware ßow control enabled. The I-modem sends data to your computer only upon receipt of the RTS signal. Alter software ßow control for received data.
U.S. Robotics I-modem Command Reference Keep in mind that the XON/XOFF characters sent to the remote computer may interfere with XON/XOFF signaling between the remote computer and remote device. See &I2. &I2 The I-modem acts on your XON/XOFF commands, but removes them from the data stream instead of passing them to the remote computer. This ensures that the remote computer does not confuse your XON/XOFF characters with those from its attached device. This is the recommended setting for ARQ mode.
U.S. Robotics I-modem Command Reference &I4 Hewlett PackardÐTerminal mode. Applies only to I-modems attached to terminals in an HP system that uses the ENQ/ACK protocol. Use in ARQ mode only. &I5 Enable ßow control when the connection is not under error control. For this to work, the remote device must also have &I5 capability. In ARQ mode, an I-modem set to &I5 operates the same as it does when set to &I2. It acts on your XON/XOFF commands, but does not pass them to the remote system.
U.S. Robotics I-modem Command Reference and preventing their own deviceÕs buffer from overßowing. At the computer/device interfaces, the devices independently control the ßow of data through their Transmit Data (&H) settings. Transmit-Data Flow Control This type of ßow control is for data transmitted to the I-modem by its attached computer. Non-ARQ connections allow the use of error control Þle transfer protocols, such as XMODEM and YMODEM without ßow control. &Hn Alter the transmit-data ßow control.
U.S. Robotics I-modem Command Reference &H3 Use both hardware and software ßow control. If you are unsure about what your equipment supports, select this option.
U.S. Robotics I-modem Command Reference Chapter 11 Handshaking, Error Control, Data Compression, and Throughput Handshaking With each call, the I-modem goes through a link negotiation process with the remote device. Another name for the negotiation process is Òhandshaking.Ó The way in which the I-modem handles outgoing and incoming calls depends on the call type setting youÕve chosen.
U.S. Robotics I-modem Command Reference Universal Connect When you set the I-modem to Universal Connect and make or receive a call, the I-modem tries a number of calls and detection processes. Call Call Type Protocol 1 64 Kbps Digital V.120 2 56 Kbps Digital V.120 3* £19.2 Kbps Digital V.110 4 3.1 kHz Audio V.34/V.FC/V.32terbo/etc. *A Note About V.110 Connections V.110 connections are not attempted by default. The I-modem attempts a V.110 connection only if you set S67.0=1. When V.
U.S. Robotics I-modem Command Reference By default, In-band Monitoring is active during every connection attempt the I-modem makes. You can, however, disable parts of the monitoring process. Monitor If detected, the I-modemÉ To disable If disabled and then detected, I-modemÉ 64 Kbps V.120 Connects at 64 Kbps V.120 S67.1=1.2=0 Ends connection attempt 56 Kbps V.120 Connects at 56 Kbps V.120 S67.1=1.2=1 Ends connection attempt Voice Tries call again at 3.1 kHz S68.
U.S. Robotics I-modem Command Reference By default, the I-modem tries to establish a multilink PPP (MP-PPP) session. You can set up the I-modem to skip either the 64 Kbps or the 56 Kbps call. To skip the 64 Kbps call, set S67.1=1.2=0. To skip the 56 Kbps call, set S67.1=1.2=1. You can change whether the I-modem makes one or two calls by a combination of bit 3, Sregister 68 and the use of an ampersand (&) in the dial string, as shown in Table 11-1. Number of calls made Dial string S68.3=0 S68.
U.S. Robotics I-modem Command Reference V.120 Rate Adaptation If you set the I-modem to V.120, it will negotiate only for V.120 connections. If a V.120 connection cannot be made, the I-modem does not negotiate for other types of connections. V.110 Rate Adaptation If you set the I-modem to V.110, it will negotiate only for V.110 connections. If a V.110 connection cannot be made, the I-modem does not negotiate for other types of connections.
U.S. Robotics I-modem Command Reference the highest compatible modulation scheme (V.FC, V.32terbo, V.32bis, and so on, down to as low as Bell 103, or 300 bps). If the remote analog device has V.34 capability, the I-modem uses a line-probing technique to determine the highest speed possible under current line conditions, then completes the connection. If the remote analog device does not have V.
U.S. Robotics I-modem Command Reference connection. If the remote analog device does not have V.FC capability, the I-modem listens to the deviceÕs answer tones to identify what standard rate the remote analog device is operating at, and then adjusts to that rate. When the I-modem answers a call from an analog device, the I-modem sends out a series of answer tone signals until both devices negotiate the best connection rate. USR V.32terbo to USR V.
U.S. Robotics I-modem Command Reference ¥ V.32terbo: 19.2 Kbps, with an additional USR device-to-USR device speed of 21.6 Kbps. ¥ V.32bis: 14.4 Kbps. ¥ V.32, V.22bis, etc.: 9600 bps and lower. ASL (used in V.32terbo and V.32bis modes) is a technique that allows the I-modemÕs receivers and transmitters to act independently of each other. One transceiver may slow down and then speed up without affecting the data ßow on the other. The result is more efÞcient line operation. Note When answering using V.
U.S. Robotics I-modem Command Reference instance that this may be necessary. (See Appendix A, Alphabetic Command Summary.) Dual Standard Handshaking We recommend that I-modems retain the default B0 and &N0 settings. This allows them to make analog connections with ÒV.Ó protocol and HST modems in both Originate and Answer modes at a variety of speeds.
U.S. Robotics I-modem Command Reference If you want the I-modem connect with V. protocol modems at high speeds, make sure it is set to B0 for the ITU answer tones. It will also connect with HST modems at speeds up to 16.8 Kbps. Error Control I-modems employ error-control techniques only during V.120 and analog connections. Note High-speed analog calls are highly vulnerable to errors unless the data is protected by error control.
U.S. Robotics I-modem Command Reference Error control is available for calls at 1200 bps and above. It can be disabled, although high-speed analog calls (9600 bps or higher) should always be under error control. The operations deÞned in an error-control protocol include: ¥ Establishing compatibility. ¥ Formatting data frames. ¥ Detecting errors using Cyclic Redundancy Checking (CRC). ¥ Retransmitting corrupt data frames.
U.S. Robotics I-modem Command Reference ¥ A Link Access Procedures for Modems (LAPM) nego-ti-ation phase, during which the devices identify their capabilities concerning maximum data block size and the number of outstanding data blocks allowed before an acknowledgment is required. MNP Error Control The Microcom Networking Protocol (MNP) is supported by the ITU-T V.42 Recommenda-tion. It was originally developed by Microcom, Inc. and is now in the public domain. MNP is based on special protocol frames.
U.S. Robotics I-modem Command Reference Error-Control Commands &Mn Enable ARQ (error control) or enable synchronous protocols. The I-modem and the remote device must use the same protocol. &M0 Normal mode, no error control. Due to the nature of phone line channels, this is never recommended for analog calls above 2400 bps. &M1 Online synchronous mode without V.25bis. External I-modems only. &M4 Normal/ARQ mode. Operate in Normal mode (&M0) if an ARQ connection canÕt be made. Note When V.
U.S. Robotics I-modem Command Reference &M6 Start V.25bis synchronous mode, using a character-oriented link protocol similar to BISYNC. (External I-modems only.) &M7 Start V.25bis synchronous mode, using the HDLC link protocol. (External I-modems only.) Data Compression I-modems employ different data compression techniques during analog and TurboPPP (digital) connections. TurboPPP When a call uses TurboPPP, the I-modem supports three kinds of compression: Ascend, Microsoft, and Stac.
U.S. Robotics I-modem Command Reference Analog If an I-modem successfully establishes a V.42 error control connection with a remote device, it also negotiates for V.42bis data compression. If the I-modem successfully establishes an MNP connection with a remote device, it also negotiates for MNP5 data compression.
U.S. Robotics I-modem Command Reference Possible dictionary sizes: Bits Entries 9 512 10 1024 11 2048 I-modems use an 11-bit, or 2048-entry dictionary, but they can reduce its size to accommodate a remote modem that uses a 9- or 10-bit dic-tionary. ¥ Maximum string length of each entry. As the dic-tionary Þlls, the I-modem deletes the oldest unused strings. V.42bis compression is more efÞcient than MNP5 com-pression, in part because it dynamically deletes entries that are no longer used.
U.S. Robotics I-modem Command Reference This allows V.42bis compression to work dynamically with the com-pressed data, but disables MNP5. Data Compression Commands &Kn Enable/disable data compression. &K0 Disable analog and TurboPPP data compression. &K1 Auto enable/disable. Enable compression if the serial port rate is Þxed (&B1).
U.S. Robotics I-modem Command Reference Getting Maximum Throughput The following guidelines should help you to make the most of the I-modem's advanced performance features. In many instances, experimentation and experience will indicate what works best for your applications. Maximum throughput results when: ¥ The communications software allows Þxing the serial port rate higher than the connection rate by setting the soft-ware to 230400, 115200, 57600, or 38400 bps and setting the I-modem to &B1.
U.S. Robotics I-modem Command Reference ¥ MNP5 compression is disabled for Þles that are already compressed and 8-bit binary Þles that appear to the I-modem to be already compressed. Disable MNP5 compressing by sending the I-modem &K3. ¥ The Þle transfer is not slowed down by a File Transfer Protocol. Many non-text Þles require a File Transfer Protocol, but the results vary.
U.S. Robotics I-modem Command Reference The protocols listed above further reduce throughput when an error control connection is established. The accuracy of the data is checked both by the File Transfer Protocol and the I-modem. To avoid redun-dancy, use the above protocols only for non-ARQ connections, and only at speeds of 2400 bps and below. Overhead is minimal with ZMODEM, resulting in throughput that is almost equal to that obtained with no File Transfer Protocol.
U.S. Robotics I-modem Command Reference Chapter 12 Querying Each channel in the multiport I-modem can display information such as the current settings, product code, and call duration. The most commonly used inquiry commands are: In ATI4 Current settings ATI5 NVRAM settings ATI6 Link diagnostics summary ATI12 ISDN conÞguration summary Display the results of a query. I0 Display a four-digit product code. If you have a problem and you call U.S.
U.S. Robotics I-modem Command Reference I1 Perform a checksum of the I-modemÕs read-only memory (ROM) and display the results. (This function is used only in factory testing.) The I-modem should always display the same number. I2 Perform a test of the I-modemÕs random-access memory (RAM) and display either OK (0) or ERROR (4), followed by OK when the test is completed. You may want to use this command if the I-modem appears to be malfunctioning.
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U.S. Robotics I-modem Command Reference I6 Display a diagnostic summary. During a connection, the I-modem monitors and stores information about link operations. When the call is ended, you can request a diagnostic summary. The duration of the last call or the real time is displayed, depending on the Kn setting. For calls under data compression, the number of characters sent may be less than the number of octets sent, due to buffering operations. ati6 USRobotics Courier I-modem with ISDN/V.
U.S. Robotics I-modem Command Reference Fallback Protocol Speed Last Call Disabled SYNC 64000 00:01:32 Disconnect Reason is Normal call clearing OK Figure 12-3. Link Diagnostics Screen (I6) Term Used in I6 Meaning Octets Compressed data units. If the number of octets is greater than the number of characters sent, the devices probably used MNP5 compression on an already compressed Þle, and the result was expanded data.
U.S. Robotics I-modem Command Reference Term Used in I6 Meaning Data Compression Indicates the type of data compres-sion negotiated for the call (V42BIS or MNP5) or NONE. A V42BIS response includes the size of the dictionary and the maximum string length used, for example, 2048/32. (See Chapter 11 for more detail.) Equalization Long/Short Status of S15 bit 0; long if bit 0=0, short if bit 0=1.
U.S. Robotics I-modem Command Reference Disconnect Reasons Table 12-2 explains the disconnect reasons that are displayed in the ATI6 response. Messages pertaining to analog connections are indicated by italics. Disconnect Reason Explanation A Rootless Tree The I-modem received an invalid V.42bis (compression) frame. Bearer capability not authorized You have requested a B-channel capability you are not authorized to use.
U.S. Robotics I-modem Command Reference Disconnect Reason Explanation Call rejected The device you tried to call refused to accept the call, and it is not busy or incompatible. Channel type not implemented You have reached an unsupported channel type. Channel unacceptable The device you are trying to call cannot negotiate for any channel other than the one speciÞed in the SETUP message. Circuit/channel congestion There is no appropriate circuit (channel) to handle your call request.
U.S. Robotics I-modem Command Reference Disconnect Reason Explanation GSTN (General The connection was non-ARQ, and DTR was dropped from one side of the connection; or the DISC frame was corrupted due to noise. Switch Telephone Network) Clear Down IdentiÞed channel does not exist You sent a request to use a channel that is not activated. Illegal command code The I-modem received an invalid V.42bis (compression) frame.
U.S. Robotics I-modem Command Reference Disconnect Reason Interworking class, unspeciÞed Explanation Your call went through a network that cannot provide messages, so you wonÕt know what the causes for any problems were. Invalid call refer- You sent a message with a Òcall referenceÓ that canÕt currently be used. ence value Invalid codeword The I-modem received an invalid V.42bis (compression) frame.
U.S. Robotics I-modem Command Reference Disconnect Reason Loss of carrier Explanation The I-modem detected a loss of the remote deviceÕs carrier and waited the duration speciÞed in Register S10 (default is 0.7 seconds). Mandatory infor- The message you sent cannot be processed because it is missing one or more mation element mandatory elements. is missing Message not compatible with call state You sent a message that could not be received because of the receiving deviceÕs call state.
U.S. Robotics I-modem Command Reference Disconnect Reason Explanation No user responding The user has not responded to the call with either an ALERT or CONNecting indication within a speciÞed amount of time. Non-selected user clearing The user was not awarded the incoming call. Normal call clearing The call ended at the request of one of the users Normal, unspeciÞed A ÒnormalÓ event occurred that doesnÕt Þt any of the other normal descriptions.
U.S. Robotics I-modem Command Reference Disconnect Reason Explanation Requested channel not available The channel you requested is not available: itÕs engaged or out of service. Requested facility not implemented You cannot access the facility you requested because itÕs not implemented. Requested facility not subscribed You cannot access this facility because you are not subscribed to it.
U.S. Robotics I-modem Command Reference Disconnect Reason Explanation A Òservice or option not availableÓ event occurred that doesnÕt Þt any of the other Service or option not avail- service or option-not-available descriptions. able, unspeciÞed Service or option not implemented, unspeciÞed A Òservice or option not implementedÓ event occurred that doesnÕt Þt any of the other service or option not implemented descriptions. Switching equip- Heavy trafÞc at the switch.
U.S. Robotics I-modem Command Reference Disconnect Reason User busy Explanation Though the userÕs equipment is compatible with the call, it has no resources to handle the call. User information Could not deliver user information to the remote user as requested. discarded XID timeout The devices failed to negotiate the V.42 Detection (XID Exchange) phase.
U.S. Robotics I-modem Command Reference Disconnect Reasons for Dial Security Table 12-3. Dial Security Disconnect Reasons Disconnect Reason Explanation Mode Incompatible The I-modem hung up because both devices were not set to the same error-control setting. No Prompting in Non-ARQ Prompting was enabled, but the I-modem hung up because the originating device was set for error control, and the answering device was set for non-error control.
U.S. Robotics I-modem Command Reference I10 Display the Dial Security Account status. For security administrators only, unless local security is disabled (S53=0 or S53.2=0). ati10 U.S. Robotics Total Control I-modem with ISDN/V.
U.S. Robotics I-modem Command Reference I11 Displays a connection report that U.S. Robotics Technical Support representatives use to help you solve problems. I12 Displays the ISDN settings that are stored in NVRAM and gives the current status of the ISDN physical interface and the data link layer. ati12 USRobotics Courier I-modem with ISDN/V.34 ISDN Switch Settings... Switch Protocol Multipoint Dialing Mode SPID Directory No.
U.S. Robotics I-modem Command Reference Chapter 13 Displaying Help Screens Multiport I-modems provide six help, or command summary, screens: basic AT command set, ampersand (&) command set, percent (%) command set, asterisk (*) command set, dial command options (D), and S-Registers (S). Important External I-modems only: Help screens are not available when an I-modem makes a synchronous connection using &M1, &M6, or &M7. Stop/Restart Display Hold down the Control key and type "S" to stop the display.
U.S. Robotics I-modem Command Reference Basic Command Set ($) When you send AT$, the I-modem displays a screen that shows a partial summary of the basic command set. (See Figure 13-1.) at$ HELP, &$ %$ A/ A> AT A Bn Cn Dn DL DSn D$ En Command Quick Reference (CTRL-S to Stop, CTRL-C to Cancel) HELP, Ampersand Commands HELP, Percent Commands Repeat Last Command Continuously Repeat Command Command Mode Prefix Answer Call n=0 V.
U.S. Robotics I-modem Command Reference Fn Hn In n=0 n=1 n=0 n=1 n=0 n=1 n=2 n=3 n=4 n=5 n=6 n=7 n=10 n=11 n=12 Online Echo No Online Echo On Hook (Hang Up) Off Hook Product Code Checksum RAM Test Modem Identification Current Settings NVRAM Settings Link Diagnostics Product Configuration Dial Security Status V.
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U.S. Robotics I-modem Command Reference &Kn &Ln &Mn &Nn n=3 n=4 n=5 n=0 n=1 n=2 n=3 n=0 n=1 n=0 n=1 n=4 n=5 n=6 n=7 n=0 n=1 n=2 n=3 n=4 n=5 n=6 n=7 n=8 n=9 n=10 n=11 n=12 n=13 HP Enq/Ack Host Mode HP Enq/Ack Terminal Mode Xon/Xoff for non-ARQ Mode Disable Data Compression Auto Data Compression Enable Data Compression Selective Data Compression Reserved Reserved Normal Mode Synchronous Mode ARQ/Normal Mode ARQ Mode V.25bis V.
U.S. Robotics I-modem Command Reference n=14 28800 bps n=15 31200 bps n=16 33600 bps OK Figure 13-2. Ampersand Commands Help Screen (AT&$) S-Registers (S$) When you send ATS$, the I-modem displays a screen that shows a partial summary of the S-register functions. More screens, which are activated when you press any key, show the remaining registers. (See Figure 13-3.
U.S. Robotics I-modem Command Reference S7 S8 S9 S10 S11 S12 S13 Wait Time/Carrier (sec) 1 = MNP/V.42 Disabled in V.22 Comma Time (sec) 2 = MNP/V.42 Disabled in V.22bis Carrier Detect Time (1/10sec) 4 = MNP/V.42 Disabled in V.
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U.S. Robotics I-modem Command Reference S30 S31 S32 S33 S34 S35 S36 S37 S38 S39 Reserved Reserved Reserved Reserved Bit Mapped 1 = Disable V.
U.S. Robotics I-modem Command Reference Percent Command Set (%$) When you send AT%$, the I-modem displays a screen that shows a partial summary of the percent command set. A second screen, which is activated when you press any key, shows the remaining commands. (See Figure 13-4.
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U.S. Robotics I-modem Command Reference at*$ HELP, Asterisk Commands (CTRL-S to Stop, CTRL-C to Cancel) *S1=n..n *S2=n..n *P1=n..n *P2=n..n *V1=n *V2=n *W=n *M=n *O=n Voice Service Profile Identifier (SPID0) Data Service Profile Identifier (SPID1) Voice Directory Number (DN0) Data Directory Number (DN1) Voice Bearer Capability (DN0) n=0 3.1 Khz Audio n=1 Speech Data Bearer Capability (DN1) n=0 Auto Detect n=1 V.120 Rate Adaption (Fixed) n=2 V.
U.S. Robotics I-modem Command Reference *T1=nn *T2=nn *Cn Voice channel TEI nn=0 Automatic nn=1-63 Fixed TEI Data channel TEI nn=0 Automatic nn=1-63 Fixed TEI Audio port volume n=0 minimum : n=9 maximum assignment assignment assignment assignment OK Figure 13-5. Asterisk Commands Help Screen (AT*$) Dial Commands (D$) When you send ATD$, the I-modem displays a screen that shows a partial summary of the percent command set.
U.S. Robotics I-modem Command Reference 0-9 * # T P R , ; " W @ ! Digits to Dial Auxiliary Tone Dial Digit Auxiliary Tone Dial Digit Tone Dialing Pulse Dialing Call an Originate Only Modem Pause (Wait for S8 Time) Remain in Command Mode After Dialing Used to Dial Alpha Phone #'s Wait for 2nd Dial Tone (X3-X7) Wait for an Answer (X3-X7) Flash Switch Hook Figure 13-6.
U.S. Robotics I-modem Command Reference Chapter 14 Testing The I-modem can perform digital and remote digital loopback tests. You can use these tests to check the operations of the transmitter and receiver, or to locate a problem with a remote device or a telephone line. Test by sending an &T command or by setting Register S16. Only one test can be performed at a given time. If you send a test command while the I-modem is in test mode, you'll receive an ERROR message.
U.S. Robotics I-modem Command Reference Testing the I-modem (Using &T) Perform digital loopback and remote digital loopback testing by using the &T command. You can type in your own data during testing or use the I-modem's internal test pattern and error detector. Note Disable error control (using the &M0 command) before testing. If the Imodem is detecting errors and retransmitting the affected data, your results will be invalid.
U.S. Robotics I-modem Command Reference 1. Send the command AT&M0&N3S14.0=0 to prepare the I-modem for testing. This command disables error control, Þxes the connection rate at 2400 bps, and makes the I-modem return to Command mode when you type +++. 2. Establish a connection with the remote device. 3. Send the I-modem the +++ escape code to bring it back to Command mode. 4. Send the I-modem the AT&T3 command. The I-modem enters digital loopback mode. 5. Have the remote user type a short message.
U.S. Robotics I-modem Command Reference 7. Send AT&M4, unless you used a reset command (ATZ or ATZ!). Stopping a Test (&T0, S18) To stop a test, send an &T0 command, or set Register S18 to a speciÞed number of seconds (for example, S18=10). When the 10 seconds are up, the I-modem will stop the test automati-cally and return to Command mode. Send an ATH command to hang up the I-modem, or an ATZ command to hang up the I-modem and reset it to its defaults.
U.S. Robotics I-modem Command Reference Remote Digital Loopback Testing (&T6, &T7) This test, like the local digital loopback test, veriÞes the condition of both devices and of the phone line. Data ßow is shown in Figure 14-2. Figure 14-2. Data Flow During Remote Digital Loopback The request for and granting of remote digital loopback testing requires that both devices use ITU-T V.22 standard signaling.
U.S. Robotics I-modem Command Reference Granting a Digital Loopback Test Request (&T4) The &T4 option causes the I-modem to grant a remote device's request for a remote digital loop-back test. Canceling All Digital Loopback Test Requests (&T5) The &T5 option cancels &T4, and the I-modem fails to recognize remote digital loopback test requests. This is the default so that your I-modem isn't subject to another user calling and tying up your I-modem without your permission.
U.S. Robotics I-modem Command Reference 4. Send the I-modem the AT&T6 com-mand. The I-modem enters remote digital loopback mode, and, if the I-modem is an external model, the MR status light ßashes. 5. Type a short message. It will be looped back to your I-modem by the remote device and to your screen for veriÞcation. (The remote user will not see your data.) 6. Send the escape code, +++, and then AT&T0 to end the test.
U.S. Robotics I-modem Command Reference You don't need to type anything during this test. The I-modem sends only its Þnal error count to your screen. 1. Send the command AT&M0&N3S14.0=0 to prepare the I-modem for testing. This command disables error control, Þxes the connection rate at 2400 bps, and makes the I-modem return to Command mode when you type the escape code (+++). 2. Establish a connection with the remote device. 3.
U.S. Robotics I-modem Command Reference Register S18, the I-modem automatically ends the test when the test timeout is reached. When the test ends, the I-modem returns a three-digit code, followed by OK. A code of 000 indicates no errors were found; a code of 255 indicates 255 or more errors. Data errors indicate a problem with the remote device or with the phone link. 6. Send AT&M4, unless you used a reset command (ATZ or ATZ!). Testing the I-modem Using S16 Register S16 is a bit-mapped register.
U.S. Robotics I-modem Command Reference setting instead. To perform remote digital loopback testing with a U.S. Robotics modem that does not use the &T test repertoire, that modem should be set to S16=8. Remote Digital Loopback Testing Testing Using Keyboard Data (S16=8) 1. Send the command AT&M0&N3S14.0=0 to prepare the I-modem for testing. This command disables error control, Þxes the connection rate at 2400 bps, and makes the I-modem return to Command mode when you type the escape code (+++). 2.
U.S. Robotics I-modem Command Reference tal loopback mode. If you are using an external I-modem, the MR status light ßashes during this operation. 5. Type a short message. It will be looped back to your I-modem by the remote device and to your screen for veriÞcation. (The remote user will not see your data.) 6. Send the escape code, +++, and then ATS16=0 to end the test. If you issue an invalid command, the I-modem sends an ERROR message.
U.S. Robotics I-modem Command Reference To use the test pattern during testing with S16, type the following command: AT&M0S16=12 To use the test pattern with the &T test, insert the test pattern command, S16=4, before issuing the test command: ATS16=4&T6 The test pattern (ATS16=4) is used for testing equipment and the phone line. When S16 is set to 4, the I-modem transmits the test pattern when it connects with a remote device.
U.S. Robotics I-modem Command Reference Chapter 15 Troubleshooting This chapter is divided into three sections: 1. Problems that occur before connecting. 2. Problems that occur after connecting. 3. What to do if you still have problems. Problems That Occur Before Connecting No response to AT ¥ Make sure you set the correct COM port and IRQ in your communications software and, if applicable, in WindowsÕ Control Panel Ð Ports. ¥ Make sure your communications software is in Terminal mode.
U.S. Robotics I-modem Command Reference ¥ Be sure your communications software is set to the correct bit rate and word length (7 bits with or without a parity bit, or 8 bits and no parity). ¥ Check that DIP switch 2 is ON, for Òact on AT commands.Ó If the switch is OFF, power off the I-modem, set the switch ON, and power on the I-modem again. Then try typing AT again. ¥ Make sure that verbal result codes (status messages) are enabled.
U.S. Robotics I-modem Command Reference The I-modem wonÕt accept your directory number (DN) The I-modem accepts only seven-digit DNs. Try sending the *P command, this time leaving off the area code. After you dial, the I-modem reports NO CARRIER and then hangs up ¥ You may not have set the correct SPIDs. Send ATI12 and check the Physical Interface and Data Link Layer entries. Both should read Active. If you have set the wrong SPID, Data Link Layer reads Active (Incorrect SPID).
U.S. Robotics I-modem Command Reference The I-modem wonÕt dial Check your communications softwareÕs manual to Þnd out which Data Terminal Ready (DTR) setting it requires. You may need to change the DTR setting at the I-modem. If so, see Chapter 6, Controlling EIA-232 Signaling. Hear ringing, but the I-modem wonÕt answer ¥ Check your communications softwareÕs manual to Þnd out what DTR operations your software requires.
U.S. Robotics I-modem Command Reference The I-modem behaves as if were pressed when you donÕt press any keys Your software may be misreading signals from the I-modem when the I-modem sends a Carriage Return and a Line Feed before and after the RING and CONNECT messages. Sending the Quiet mode command, ATQ1 , should solve the problem.
U.S. Robotics I-modem Command Reference If the I-modem is set to a Þxed serial port rate (&B1) and your software is Þxed at 19200, 38400, 57600, or 115200 Kbps, the reason may be one of the following: ¥ Your computer may not support the higher serial port rate. If this is the case, Þx your software rate at 9600 bps and disable high-speed V.32terbo modulation: ATS34=3 or ATS34.0=1.1=1.
U.S. Robotics I-modem Command Reference Connects at 64 Kbps or 56 Kbps, but canÕt pass data Your telephone company may be providing incorrect connection speed information. Try forcing the connection speed to 56 Kbps by sending ATS67.1=1 and ATS67.2=0. If you still canÕt pass data, try forcing the connection speed to 64 Kbps by sending ATS67.1=1 and ATS67.2=1. Any problems will likely be conÞned to one phone number, so after the call, change the setting back to auto-sense, ATS67.1=0.
U.S. Robotics I-modem Command Reference Bad faxes or canÕt fax ¥ Make sure the fax software is set to use Class 1 fax. Refer to your fax softwareÕs manual. ¥ If you use memory-resident programs (TSRs Ð Terminate and Stay Resident programs) or disk-caching programs, they may be interfering. Try disabling them before you run your com-muni-cations software.
U.S. Robotics I-modem Command Reference ¥ Make sure your I-modem's connection rate setting, &Nn, is correct for the call. If the connection rate is locked at a speed (&N1*&N14) different from the calling modem's, the I-modem hangs up. The default setting of &N0 (variable link operations) allows the two modems to negotiate the highest possible connection rate. ¥ If your modem is attempting to answer a V.32 call, you may need to lengthen the extra V.32 answer tones.
U.S. Robotics I-modem Command Reference If You Still Have Problems The problems described above are the most common ones users encounter. If the suggestions we've given don't clear up the difÞculties, try the following: 1. Review the manual carefully to see if youÕve missed something. 2. Call or visit your dealer, who will probably be able to assist you. This is much more efÞcient (and time-saving) than returning the product to U.S. Robotics. 3.
U.S. Robotics I-modem Command Reference b. Be sure to include your SRO number inside the package, along with your name and address. Put your return address and SRO number on the shipping label, as well. c. Ship the package to: Cor/Sys Technical Support U.S. Robotics Access Corp. 8100 North McCormick Boulevard Skokie, Illinois 60076-2999 Note U.S. Robotics will not accept packages sent COD, so be sure to send the modem postage-paid. U.S.
U.S. Robotics I-modem Command Reference Chapter 16 Analog Synchronous Applications This chapter applies to situations in which you want the I-modem to work with devices, such as mainframe computers, that communicate using analog, synchronous protocols. The I-modem must be connected to a synchronous serial port. Note These procedures do not apply to synchronous PPP calls. There are two ways to operate the I-modem in analog synchronous mode: ¥ Dial Using V.25bis Software.
U.S. Robotics I-modem Command Reference Requirements You must have these before you start: A Device with a Synchronous Serial Port Find out what hardware and software you need before proceeding. You will probably have to purchase and install a synchronous adapter card. These cards provide: ¥ A synchronous serial port. ¥ Support for one or more synchronous protocols. ¥ Additional software functions. For example, the card may tell the mainframe what type of computer or terminal you are using.
U.S. Robotics I-modem Command Reference Transmit and Receive synchronous timing pins are required at the EIA-232 interface. Pins 15 and 17 are required: The I-modem transmits timing signals through pin 15 and receives timing signals through pin 17. Communications Software The devices at both ends of the link must use the same synchronous protocol. Ask your network administrator about the software support (for example, a speciÞc communications package) that you need to log into the network.
U.S. Robotics I-modem Command Reference Dial Using V.25bis Software To make synchronous connections using V.25bis communications software, you must Þrst conÞgure the I-modem using AT commands. Once the I-modem is conÞgured, run your communications software, which takes control of the I-modem for the duration of the connection.
U.S. Robotics I-modem Command Reference &M7 Dial using the High Level Data Link Control (HDLC) protocol. HDLC ignores parity. Example: AT&M7&W selects HDLC. 2. Set the ofßine clock speed, or the clock speed to be used (between the I-modem and the computer to which it is directly attached) when the I-modem is not engaged in a synchronous connection.
U.S. Robotics I-modem Command Reference 3. Choose a connection rate to be used (between the I-modem and the remote communications device) when the I-modem is online. If &Nn is set for 2*10, the I-modem ignores the %Nn rate and uses the &Nn rate as the online connection rate. Note &N0 Variable (default) &N8 14.4 Kbps &N1 Reserved &N9 16.8 Kbps &N2 1200 bps &N10 19.2 Kbps &N3 2400 bps &N11 21.6 Kbps &N4 4800 bps &N12 24.0 Kbps &N5 7200 bps &N13 26.4 Kbps &N6 9600 bps &N14 28.
U.S. Robotics I-modem Command Reference Example: AT&N10%N10&W selects a connection rate and an ofßine clock speed of 19200 bps. 4. Choose whether the I-modem should display normal or extended synchronous result codes. Depending on the setting of the Xn command, the I-modem displays normal or extended synchronous result codes. Extended result codes provide more detailed information.
U.S. Robotics I-modem Command Reference Note Due to the nature of synchronous dial-up, the I-modem auto-answers only on the third or fourth ring. 6. Set the I-modem to enter clear-channel synchronous mode.
U.S. Robotics I-modem Command Reference commands are no longer necessary and are ignored. For dialing instructions, refer to the manual included with your communications software. Hanging Up Since the I-modem cannot accept commands once it is connected in synchronous mode, you cannot use the ATH (hang-up) command or the +++ escape code. The only way for the I-modem to disconnect is to drop its Data Terminal Ready (DTR) signal.
U.S. Robotics I-modem Command Reference Commands CIC Connect incoming call Instructs the I-modem to answer an incoming call. CRN Call request using number provided Instructs the I-modem to dial the number following this command. Example: CRN18005551234 CRS Call Request with memory location Instructs the I-modem to dial a number stored in memory. Example: CRS3 DIC Disregard incoming call Instructs the I-modem to disregard an incoming call Ð overrides auto answer for this call.
U.S. Robotics I-modem Command Reference > (Greater Than) separator < Pause = (Equal Sign) separator P Pulse T Tone . (Period) separator - (Minus) separator Result Codes These are the normal (X0) result codes.
U.S. Robotics I-modem Command Reference LSN List of stored numbers VAL Valid These are the extended result codes (X1) that replace CFI and INV.
U.S. Robotics I-modem Command Reference Commands and Result Codes NOT Supported CRI Call request with identiÞcation number PRI Program identiÞer RLD List of delayed call numbers RLI Request list of identiÞcation numbers Synchronous Dialing Using AT Commands To use AT commands to dial, you must set the I-modem to enter online synchronous mode when you dial. You then dial the remote deviceÕs number using AT commands.
U.S. Robotics I-modem Command Reference Note Data Terminal Ready (DTR) override must be OFF when using the Imodem in online synchronous mode. Use &D1 or &D2. See Chapter 6, Controlling EIA-232 Signaling. ConÞguring the I-modem 1. If your communications software isn't running, load the program and start Terminal mode (see your software userÕs guide for instructions). 2. Send AT&F0B0&X0 . The device you are calling should also be set to the equivalent of B0, which tells the Imodem to use the V.
U.S. Robotics I-modem Command Reference &N3 2400 bps &N11 21.6 Kbps &N4 4800 bps &N12 24.0 Kbps &N5 7200 bps &N13 26.4 Kbps &N6 9600 bps &N14 28.8 Kbps &N7 12.0 Kbps &N15 31.2 Kbps &N16 33.6 Kbps Example: AT&N0 Notes ¥ If an I-modem is set to a Þxed rate, and the remote device is not set to the same rate, the I-modem hangs up. ¥ I-modems cannot connect at 21.6 Kbps in synchronous mode. ¥ HST and V.FC modulations do not support synchronous communications. 4.
U.S. Robotics I-modem Command Reference Note Due to the nature of synchronous dialup, the I-modem auto-answers only on the third or fourth ring. Example: ATS0=1 5. Set the I-modem to enter clear-channel synchronous mode. Example: AT*V2=4 Dialing 6. Send &M1 to have the I-modem enter synchronous mode, followed by the number to dial. Dial should be the last command before the Carriage Return.
U.S. Robotics I-modem Command Reference There are two methods of autodialing a stored telephone number: You can have the Imodem dial the stored number either when it receives the Data Terminal Ready (DTR) signal from your computer or at power-on/reset. 1. Store a telephone number to memory position 0 using the AT&Z0=n command. For example, to store (847) 555-1111, and tone dial, type: AT&Z0=T18475551111 2. Follow step a or b, depending on the dialing method you choose. a.
U.S. Robotics I-modem Command Reference Chapter 17 Upgrading the I-modemÕs Software U.S. Robotics periodically releases updates and enhancements to the I-modemÕs operating software. We make the software publicly available from our BBS and ftp site. To send the new code to the I-modem, all you need is a standard terminal program that can send Þles using the XMODEM protocol. Checking Your I-modemÕs Software Version Send ATI7 .
U.S. Robotics I-modem Command Reference Eprom Ram 768k 256k Supervisor date DSP date 04/02/96 09/28/95 Supervisor rev DSP rev 2.0.0 2.0.0 OK Check the Supervisor and Digital Signal Processor (DSP) dates. The best way to Þnd out the current shipping version of the I-modemÕs software is to call U.S. Robotics Technical Support at (800) 550-7800. Getting New Operating Software There are two ways to get the newest version of the I-modemÕs operating software: ¥ Call the U.S.
U.S. Robotics I-modem Command Reference ¥ Over the Internet, ftp to ftp.usr.com. Log in as anonymous and then enter your Internet e-mail address as your password. From the sys/pcb/dl05 directory, get the newest I-modem Þle with the extension XMD. Sending New Software to the I-modem 1. Start a communications software package, such as Quick Link II or MacComCenter. Adjust the settings, if necessary, so you can send AT to the I-modem and get an OK response.
U.S. Robotics I-modem Command Reference 3. Type t to start an integrity test of the XMD Þle. SDL Xmodem file transfer - (Y)es (N)o (T)est >t * Test Mode - Flash ROM will not be modified* Begin Xmodem file transfer now. CC Send the Þle to the I-modem using the XMODEM-Checksum or XMODEM-CRC protocol. Since this is a test, the I-modemÕs existing software is not erased. 4.
U.S. Robotics I-modem Command Reference Once you see the OK response to the Calculating CRC and Resetting modem messages, your software upgrade is complete! If Your I-modem DoesnÕt Respond If your I-modem doesnÕt respond, its memory may be corrupted. Follow these steps to force the new software to the I-modem. 1. Power the I-modem off. 2. Set DIP switches 1 and 2 off. 3. Power the I-modem on. 4. Start your communications software package and send the operating software using the XMODEM protocol. 5.
U.S. Robotics I-modem Command Reference Appendix A Alphabetic Command Summary This appendix contains an alphabetic listing of the AT commands to which the I-modem will respond. Default settings are bold. Basic Command Set $ Display help for the Basic command set. +++ Escape code. Once an I-modem is online with another device, the only command it recognizes is an escape code of three typed plus signs, which forces the modem back to Command mode.
U.S. Robotics I-modem Command Reference 3Wait 1 second before typing any data. When you type +++, the I-modem will either hang up or stay on line, depending on how you set S14. > Repeat command. If you include the repeat command in the Dial string, the Imodem will dial the number and wait 60 seconds for a carrier. AT>DT1234567 or ATDT1234567> If the line is busy, the I-modem will pause for 2 seconds and then redial. The Imodem makes a maximum of 10 attempts.
U.S. Robotics I-modem Command Reference A Force an I-modem to answer when it is not receiving an incoming call. Bn Set handshaking options. Cn Dn B0 ITU-T V.25 answer sequence; required to answer all V.34-type and overseas calls. B1 Bell answer tone. This setting selects HST modulation, but use it only if the I-modem is not required to answer V.34-type calls. Enable or disable the transmitter. C0 Transmitter disabled; for receiving only. C1 Transmitter enabled.
U.S. Robotics I-modem Command Reference Notes With the exception of the Dial options, I-modems ignore any commands issued after D in the same command string. Optional parameters: P Dial using pulses. Accepted but ignored. T Dial using tones. Accepted but ignored. , (Comma) Pause for 2 seconds (or the time in S-register 8). ; (Semicolon) Remain in Command mode after dialing. " Dial the letters that follow. W Wait for a second dial tone before continuing dialing (with X3 or higher).
U.S. Robotics I-modem Command Reference R Reverse frequencies. Use this command when calling an originate-only modem. It forces the I-modem to dial out at the answer frequency. En Notes L? Display the last-dialed number. L Dial the last-dialed number. Sn Dial the number stored in memory at position n, where n = 0*9. Store the number in memory using the &Z command. $ Display help for the dial commands. Command mode echo. Enables or disables the display of your typed commands.
U.S. Robotics I-modem Command Reference Fn Hn Online local echo. If ON, an I-modem displays on your screen the data that it is transmitting to another modem. F0 Online echo ON. (Sometimes called half duplex.) F1 Online echo OFF. (Sometimes called full duplex.) Go on or off hook. H0 In Go on hook (hang up). Query the I-modem. I0 Display the four-digit product code. I1 Display results of ROM checksum test (factory test). I2 Display results of RAM test. I3 Displays the banner (product name).
U.S. Robotics I-modem Command Reference Kn On I5 Display settings stored in NVRAM. I6 Display statistics for the last call. I7 Display product conÞguration. I10 Display dial security account status information. I11 Display connection report (contains symbol rates). I12 Display the ISDN settings. Control the modem clock. I6 displays the time. K0 If online, display current call duration. If ofßine, display last callÕs duration. K1 Display the actual time.
U.S. Robotics I-modem Command Reference Qn S$ O0 Return online (normal). O1 Return online and retrain. Use O1 if there were errors in a non-ARQ data transfer. Enable or disable the display of result codes. Q0 Display result codes. Q1 Suppress result codes (quiet). Q2 Suppress result codes when answering. Display help screens for the S-registers. Sr=n Set S-register value: r is any S-register; n must be a decimal number between 0 and 255. Sr.
U.S. Robotics I-modem Command Reference Note See the S-registers listing later in this appendix. Vn Display result codes in words or numbers. Xn V0 Display result codes in numeric form. V1 Display result codes in verbal form. Control the amount of information displayed in the result codes. The default is X7 (all codes except 12/VOICE). For result codes in synchronous operations, see Chapter 16, Analog Synchronous Applications. Table A-1.
U.S. Robotics I-modem Command Reference Table A-1.
U.S. Robotics I-modem Command Reference Table A-1.
U.S. Robotics I-modem Command Reference Z! Hardware reset (equivalent to powering off and then back on). If DIP Switch 1 is ON (factory setting), revert to the settings in NVRAM. If DIP switch 1 is OFF, reset to the &F0 conÞguration template (no ßow control). Ampersand (&) Command Set &$ Display help for the ampersand (&) command set. &An Enable or disable the display of additional result code subsets. (Also, see the Xn command.) &A0 Do not display ARQ result codes. &A1 Display ARQ result codes.
U.S. Robotics I-modem Command Reference &Bn Set the serial port rate to variable or Þxed. Note The serial port rate must be equal to or higher than the &Nn rate. &Cn &B0 Variable: The serial port rate adapts to match the speed of the connection. &B1 Fixed: The I-modem always communicates with your computer at the rate at which you have set, regard-less of the connection rate. &B2 When answering calls, use the Þxed rate for ARQ calls and variable rates for non-ARQ calls.
U.S. Robotics I-modem Command Reference &D1 If issued before connecting with another device, the I-modem can enter Online command mode during a call by dropping DTR. &D1 functions similarly to the escape code (+++). Return online with the On command, or hang up with the Hn command. &D2 Normal DTR operations. The modem will not accept commands unless your computer sends a DTR signal. Dropping DTR ends a call. &Fn Load one of the three conÞguration templates that are stored permanently in readonly memory.
U.S. Robotics I-modem Command Reference &Gn &F1 Load Hardware Flow Control template settings. &F2 Load Software Flow Control template settings. Set guard tones for international calls. &G0 No guard tone. Use this in the United States and Canada. &G1 This sets a 550 Hz guard tone, and is used in some European countries. &G2 This sets an 1800 Hz guard tone, and is used in the U.K. and some Commonwealth countries. &G2 requires the B0 setting. &Hn Transmit data ßow control.
U.S. Robotics I-modem Command Reference &In &H2 Use software ßow control. Requires that your software support XON/ XOFF signaling. &H3 Use both hardware and software ßow control. If you are unsure about what your equipment supports, select this option. Received data software ßow (XON/OFF) control. &I0 Disables XON/XOFF ßow control of received data. &I1 The I-modem acts on your typed XON/XOFF commands, Ctrl-S or Ctrl-Q, and passes them to the remote device.
U.S. Robotics I-modem Command Reference &Kn &I4 Hewlett Packard-Terminal mode. Applies only to I-modems attached to terminals in an HP system that uses the ENQ/ACK protocol. Use in ARQ mode only. &I5 This setting is designed to enable ßow control on the phone link when the connection is not under error control. For this to work, the remote device must have &I5 capability. Enable or disable data compression. &K0 Disable data compression. &K1 Use auto-enable/disable.
U.S. Robotics I-modem Command Reference &K3 &Ln Selective data compression. The I-modem negotiates only for V.42bis compression, and disables MNP Level 5 (MNP5) compression. Use this setting to transfer 8-bit binary Þles, .ZIP Þles, and other Þles that are already compressed. Line type. &L0 Normal. &Mn Enable ARQ (error control) or synchronous protocols. Both your I-modem and the remote device must use the same protocol. &M0 Normal mode, no error control.
U.S. Robotics I-modem Command Reference &M5 ARQ asynchronous mode. The I-modem hangs up if an ARQ connection cannot be made. &M6 V.25bis synchronous mode using a character-oriented link protocol similar to BISYNC. &M7 V.25bis synchronous mode using the HDLC link protocol. &Nn Connection rate variable or Þxed (analog connections only). &N0 Variable rate. The I-modem negotiates with the remote device for the highest possible connection rate, depend-ing on the capabilities of the remote device.
U.S. Robotics I-modem Command Reference &Rn &N1 300 bps &N9 16800 bps &N2 1200 bps &N10 19200 bps &N3 2400 bps &N11 21600 bps &N4 4800 bps &N12 24000 bps &N5 7200 bps &N13 26400 bps &N6 9600 bps &N14 28800 bps &N7 12000 bps &N15 31200 bps &N8 14400 bps &N16 33600 bps Received data (RTS) hardware ßow control. &R0 Delay Clear to Send (CTS) response after Request to Send (RTS). &R1 Ignore RTS.
U.S. Robotics I-modem Command Reference &Sn &Tn Send the computer a Data Set Ready (DSR) signal via the EIA-232 interface. (ÒData SetÓ is industry jargon for modem.) &S0 DSR is always ON (override). &S1 In Originate mode: Send DSR after dialing, on detection of the remote deviceÕs answer tone. In Answer mode: Send DSR after sending an answer tone. &S2 When Carrier is lost, send a pulsed DSR signal with Clear to Send (CTS) following Carrier Detect (CD).
U.S. Robotics I-modem Command Reference &T3 Start local digital loopback testing. &T4 Grant a remote digital loopback test of your I-modem. &T5 Deny a remote digital loopback test of your I-modem. &T6 Start remote digital loopback testing. &T7 Start remote digital loopback with self-test and error detection. &W Write the current settings to NVRAM. &Yn Break handling. This command lets you send a break to stop data transfer without disconnecting. &Y0 Destructive, don't send break.
U.S. Robotics I-modem Command Reference &Y3 Note Nondestructive, unexpedited; the I-modem sends a break-in-sequence with data received from your computer or terminal. If the call is under MNP5 data compression, destructive breaks cause both modems to reset their data compression tables. When transmission resumes, the modems build new tables, and the result is lower-than- normal throughput. &Zn=sStore up to 10 numbers in NVRAM, where n is the position 0*9 in NVRAM, and s is the phone number string.
U.S. Robotics I-modem Command Reference &Zn=L stores the last-dialed number in position n. &Zn? Display the phone number stored in NVRAM at position n (where n = 0*9). Percent (%) Command Set %$ Display the help panels for the percent (%) command set. %An Create and conÞgure security accounts. %Bn %Cn Remotely conÞgure an I-modem's serial port rate.
U.S. Robotics I-modem Command Reference %C0 Defer conÞguration changes until the call is ended. Changes take effect for ensuing connections. %C1 Note %C1 will not reverse any changes that you wrote to NVRAM (with &W) or forced (with %C2). %C2 Note Cancel conÞguration changes and restore the original conÞguration. Force conÞguration changes to take effect immediately. We recommend against forcing conÞguration changes unless it is absolutely necessary.
U.S. Robotics I-modem Command Reference %E=4 Erase phone numbers in accounts 0*9. %E=5 Disable Account, Dialback, and New Number Þelds in accounts 0*9. %Fn Remotely conÞgure another deviceÕs data format. %F0 No parity, 8 data bits. %F1 Mark parity, 7 data bits. %F2 Odd parity, 7 data bits. %F3 Even parity, 7 data bits. %L= Set a local-access password. %Nn Set the ofßine clock speed for synchronous mode. External I-modems only.
U.S. Robotics I-modem Command Reference %N4 4800 bps %N5 7200 bps %N10 19,200 bps %Pn= Disable password security (n=0 or n=1) when no character follows the equal sign. %Pn=sSet the following password (s) for viewing privileges only (n = 0), or view and conÞguration privileges (n = 1). %Pn? Display password n. %S=n Access the security accounts. Does not disable security. %T Enable the recognition of tone frequencies of analog dialing devices.
U.S. Robotics I-modem Command Reference %V=PWn Assign the password in account n in your I-modemÕs security account as your Autopass password. Asterisk (*) Command Set *$ Display the help screens for the asterisk (*) command set. *Cn Set the volume of the sound that comes out of the analog device jack. *C0Off *C9Highest volume *M=n Set whether your connection to the telephone companyÕs switch is point-to-point or multipoint. *M=0 Point-to-point. *M=1 Multipoint. *O=n Dialing mode.
U.S. Robotics I-modem Command Reference *O=0 En-bloc dialing. Dials similarly to a cellular telephone. To complete the call, press # after dialing the number. *O=1 Overlap dialing. Dials like a standard analog telephone. *Pn=s Set the Directory Number (DN) that was assigned to you by your telephone company. *P1= The DN for the Voice B-channel. *P2= The DN for the Data B-channel. *Rn Internal I-modem only. Adjusts the ringing signal volume. 0 is quietest and 9 is loudest.
U.S. Robotics I-modem Command Reference *Tn=s Set the Terminal Endpoint ID (TEI). Your telephone companyÕs central-ofÞce switch may use automatic TEI assignment; if so, set the TEI(s) to 0. *T1= 0-63 for the Voice B-channel. *T2= 0-63 for the Data B-channel. *Vn=s Set the call type for each B-channel. *V1= 0-1 for the Voice B-channel. n Call Type 0 3.1 kHz Audio (modem/fax) 1 Speech *V2= 0-5 for the Data B-channel. n Call Type 0 Autodetect 1 V.
U.S. Robotics I-modem Command Reference n Call Type 2 V.110 rate adaption only 3 Modem or fax only 4 Clear-channel synchronous 5 Asynchronous to synchronous PPP conversion *W=n Set the switch protocol used telephone companyÕs central ofÞce.
U.S. Robotics I-modem Command Reference S-registers Table AÐ1. S-registers: Their Functions and Default Settings Register Default Function S0 0 Sets the number of rings on which to answer in Auto Answer mode. S0=0 disables Auto Answer. S0=1 enables Auto Answer and the I-modem answers on the Þrst ring. S1 0 Counts and stores the number of rings from an incoming call. S2 43 Stores the ASCII decimal code for the escape code character. Default character is Ò+Ó.
U.S. Robotics I-modem Command Reference Table AÐ1. S-registers: Their Functions and Default Settings Register Default Function S8 2 Sets the duration, in seconds, for the pause (,) option in the Dial command and the pause between command reexecutions (> and A> commands). S9 6 Sets the required duration, in tenths of a second, of the remote device's carrier signal before recognition by the I-modem.
U.S. Robotics I-modem Command Reference Table AÐ1. S-registers: Their Functions and Default Settings Register S14 S15 Default 1 0 Function 3 8 On DTR signal, autodial the number stored in NVRAM at position 0 (external I-modem only). 4 16 At power-on/reset, autodial number stored in NVRAM at position 0. 5 32 Disable HST (used for testing V.32terbo in Dual Standard I-modems). 6 64 Disable MNP Level 3 (used for testing Level 2). 7 128 Hardware reset (works like powering off and then on).
U.S. Robotics I-modem Command Reference Table AÐ1. S-registers: Their Functions and Default Settings Register Default Function Bit Value Result 0 1 Disable the I-modem's extra high-frequency equalization if it causes problems on shorter-link calls Ð for HST modulation only. 1 2 Disable online fallback. 2 4 Disable 450 bps back channel Ð HST only. 3 8 Reset non-ARQ mode Transmit buffer from 1.5K bytes to 128.
U.S. Robotics I-modem Command Reference Table AÐ1. S-registers: Their Functions and Default Settings Register Default Function 7 128 Custom applications only. *The default 1.5K byte non-ARQ buffer allows data transfer with X- and YImodem-type File Transfer Protocols without using ßow control. The 128-byte option allows remote users with slower modems to stop your transmitted data from scrolling off their screens.
U.S. Robotics I-modem Command Reference Table AÐ1. S-registers: Their Functions and Default Settings Register Default Function S21 10 Sets, in 10-millisecond units, the length of breaks sent from the I-modem to the computer or terminal. Applies to ARQ mode only. S22 17 Stores the ASCII code for the XON character.a S23 19 Stores the ASCII code for the XOFF character.a S24 150 Sets the duration, in 20-millisecond units, between pulsed DSR signals when the I-modem is set to &S2 or &S3.
U.S. Robotics I-modem Command Reference Table AÐ1. S-registers: Their Functions and Default Settings Register Default Function 2 4 Disable V.32 modulation; used for testing HST modulation. 3 8 Disable 2100 Hz answer tone to allow two V.42 devices to connect more quickly. 4 16 See next page. 5 32 See next page. 7 128 Unusual software incompatibility. Some software may not accept some result codes. This setting disables the codes and displays the 9600 code instead.
U.S. Robotics I-modem Command Reference Table AÐ1. S-registers: Their Functions and Default Settings Register Default Function S28 8 Sets the duration in tenths of a second of the extra 3000/600 Hz answer tones sent during V.32 handshaking. This gives V.32 modems additional time to connect in V.32 mode before timing out. If there is difÞculty answering older, manually operated V.
U.S. Robotics I-modem Command Reference Table AÐ1. S-registers: Their Functions and Default Settings Register S38 Default 0 Function 3 8 Enable V.23. Required for some British connections. 6 64 Disable the remote-access busy message. 7 128 Disable V.32terbo. Sets the duration, in seconds, before a forced hang-up and clearing of the Transmit buffer when DTR drops during an ARQ call. This is provided to allow time for a remote device to acknowledge receipt of all transmitted data.
U.S. Robotics I-modem Command Reference Table AÐ1. S-registers: Their Functions and Default Settings Register Default Function S51 0 Bit-mapped register. See Chapter 1, Using the AT Command Set, for instructions about how to set bit-mapped registers. S53 126 Bit Value Result 0 1 Disable MNP/V.42 for V.22 (1200 bps) 1 2 Disable MNP/V.42 for V.22bis (2400 bps) 2 4 Disable MNP/V.42 for V.32/V.32bis/V.32terbo (9600/14400/19200/21600 bps). Bit-mapped register.
U.S. Robotics I-modem Command Reference Table AÐ1. S-registers: Their Functions and Default Settings Register Default Function S54 64 Symbol rate bit-mapped register used primarily by U.S. Robotics Technical Support for debugging purposes. S55 0 Bit Value Result 0 1 Disable 2400 symbol rate. 1 2 Disable 2743 symbol rate. 2 4 Disable 2800 symbol rate. 3 8 Disable 3000 symbol rate. 4 16 Disable 3200 symbol rate. 5 32 Disable 3429 symbol rate. 6 64 Disable Call Indicate (CI).
U.S. Robotics I-modem Command Reference Table AÐ1. S-registers: Their Functions and Default Settings Register Default Function 3 S56 S67 0 0 8 Disable 64S-4D mapping. Bit-mapped register primarily used by U.S. Robotics Technical Support for debugging purposes. Bit Value Result 0 1 Disable non-linear coding. 1 2 Disable TX level deviation. 2 4 Disable preemphasis. 3 8 Disable precoding. 4 16 Disable shaping. 6 64 Disable V.34. 7 128 Disable V.FC. Bit-mapped register.
U.S. Robotics I-modem Command Reference Table AÐ1. S-registers: Their Functions and Default Settings Register S68 Default 0 Function 2 4 Fix the network rate at 64 Kbps (otherwise 56 Kbps). 3 8 AT&T 5ESS with 1 DN only: Route incoming analog calls to the Data port (otherwise to the Analog Device port). 4 16 Enable a 45-65 second link delay. For compliance with Bellcore NWT 1953.
U.S. Robotics I-modem Command Reference Table AÐ1. S-registers: Their Functions and Default Settings Register Default Function S69 0 Bit-mapped register. (See Chapter 1, Using the AT Command Set, for instructions about how to set bit-mapped registers.) Bit Value Result 0 1 Disable Plug and Play signaling. (For external I-modems only.) a. See Appendix B, ASCII Chart.
U.S.
U.S.
U.S. Robotics I-modem Command Reference Appendix C Fax Information for Programmers Fax Service Class 1 Commands +FCLASS? What mode is in useÑData or Fax? +FCLASS=n (0,1,2.0) Class identiÞcation and control. +FCLASS=? What Fax class is in use? +FTS=n (0,255) Stop transmission and pause, 10 ms. +FRS=n (0,255) Wait for silence, 10 ms. +FTM=n (3,24,48,72,73,74,96,121,122,145,146) Transmit data with carrier. +FRM=n (3,24,48,72,73,74,96,121,122,145,146) Receive data with carrier.
U.S. Robotics I-modem Command Reference FAX Service Class 2.0 Commands In addition to the standard Class 2.0 fax commands, U.S. Robotics implements the following optional Class 2.0 fax commands : +FNS=0,1 Pass-through, nonstandard negotiation byte string. +FCR=0,1 Capability to receive. +FAA=0,1 Adaptive Answer mode. +FCT=0-255 sec. Phase C Timeout +FHS=0-255 Hangup Status Code, read only. +FMS=0-3 Minimum Phase C Speed. +FBS?=500,100 Buffer size, read only.
U.S. Robotics I-modem Command Reference that use software ßow control by default, U.S. Robotics fax modems automatically change to software ßow control when entering Fax mode.
U.S. Robotics I-modem Command Reference Notes If you want to know more about the supported Class 1 fax commands, refer to the standard for the Service Class 1 fax protocol: ANSI/EIA/TIA-578-1990 (EIA-578) Asynchronous Facsimile DCE Control Standard November, 1990 Approved: October 22, 1990 For more information on Class 2.0, refer to the standard for the Service Class 2.
U.S. Robotics I-modem Command Reference Glossary Note Cross-references in the following deÞnitions are blue underlined. Symbols and Numerics 1B+D In ISDN BRI, a common conÞguration of 1 B-channel and 1 D-channel. 16550 UART The fastest type of UART that is currently available. 2B+D In ISDN BRI, a common conÞguration of 2 B-channels and 1 D-channel. 5ESS See AT&T 5ESS.
U.S. Robotics I-modem Command Reference A Adaptive Speed Leveling (ASL) Courier V.32bis and V.32terbo modems detect improved line conditions and shift upward again to the next higher speed. The modems at both ends of the connection adapt independently, each detecting and adjusting to line conditions. ASL keeps the modems online, always operating at the highest possible speed and con-stantly ensuring data integrity.
U.S. Robotics I-modem Command Reference Answer mode A state in which the modem transmits at the predeÞned high frequency of the communications channel and receives at the low frequency. The transmit/receive frequencies are the re-verse of the calling modem, which is in originate mode. application (application program) A computer program designed to perform a speciÞc function, such as a word processor or a spreadsheet. ARQ See Automatic Repeat Request.
U.S. Robotics I-modem Command Reference asymmetrical modulation A transmission technique that splits the communi-cations channel into one high-speed channel and one slower channel. During a call under asymmetrical modulation, the modem with the greatest amount of data to transmit is allo-cated the high speed channel. The modem with less data is allocated the slow, or back channel (450 bps). The modems dynamically reverse the channels during a call if the volume of data transfer changes.
U.S. Robotics I-modem Command Reference Auto Answer A feature in modems enabling them to answer incoming calls over the phone lines without the use of a telephone receiver. auto dial A feature in modems enabling them to dial phone numbers over the phone system without the use of a telephone transmitter. Automatic Repeat Request (ARQ) A general term for error-control protocols that feature error detection and automatic retrans-mission of defective blocks of data. See HST, MNP, and V.42.
U.S. Robotics I-modem Command Reference baud rate The number of discrete signal events per second occurring on a communications channel. Although not technically accu-rate, baud rate is commonly used to mean bit rate. B-channel In ISDN, a 64-Kbps channel for passing circuit-switched (or packet-switched) digital information. The ÒBÓ stands for Òbearer.Ó binary digit (bit) A 0 or 1, reßecting the use of a binary numbering system (only two digits).
U.S. Robotics I-modem Command Reference bit See binary digit. bit-mapping A technique that lets one decimal number (in this case, a number between 0 and 255) stand for up to eight separate binary settings. bit rate The number of binary digits, or bits, transmitted per second (bps). Communications channels using telephone channel modems are established at set bit rates, commonly 300, 1200, 2400, 4800, 9600, 14400, and 28800. bps The bits (binary digits) per second rate. BRI See Basic Rate Interface.
U.S. Robotics I-modem Command Reference buffer A memory area used as temporary storage during input and output operations. An example is the modem's command buffer. Another is the Transmit Data ßow control buffer used for ßow control and to store copies of transmitted frames until they are positively acknowledged by the receiving modem. byte A group of binary digits stored and operated upon as a unit.
U.S. Robotics I-modem Command Reference C call-control signaling Messages carried over the telephone network that route, set up, and tear down calls. In ISDN, call control signaling goes on over the D-channel and is kept apart from the data carried on the B-channels. call indicate A call originating tone deÞned by ITU-T recommendation V.8. carrier A continuous frequency capable of being either modulated or impressed with another information-carrying signal.
U.S. Robotics I-modem Command Reference Telecommunications Standards Sector (TSS). ITU-T replaces CCITT. For example, the Bell 212A standard for 1200 bps communication in North America was referred to as CCITT V.22. It is now referred to as ITU-T V.22. central ofÞce (CO) The facility to which devices, such as telephones, fax machines, modems, and terminal adapters, within a speciÞc geographic area of a public telephone network are connected.
U.S. Robotics I-modem Command Reference Some protocols, such as USR HST and MNP, employ advanced techniques such as longer transmission frames and data compression to increase cps. circuit-switched data (CSD) A type of switching in which one call makes up a circuit (the circuit is not shared with other calls), and data is passed across the circuit. circuit-switched voice (CSV) A type of switching in which one call makes up a circuit (the circuit is not shared with other calls), and speech or 3.
U.S. Robotics I-modem Command Reference CO See central ofÞce. Command mode When the I-modem is in Command mode, you can control it using AT commands. COM port See serial port, EIA-232. cps See characters per second. CPU Central processing unit. CRC See cyclic redundancy check.
U.S. Robotics I-modem Command Reference CSD See circuit-switched data. CSV See circuit-switched voice. CSV/D Alternating circuit-switched voice and data. See circuit-switched voice and circuitswitched data. ÒCustomÓ AT&TÕs call-control signaling protocol that was implemented before the advent of NI-1. cyclic redundancy check (CRC) An error-detection technique consisting of a cyclic algorithm performed on each block or frame of data by both sending and receiving modems.
U.S. Robotics I-modem Command Reference high-speed modems, the receiving modem accepts no more data until a defective block is received correctly. D data B-channel The I-modem distinguishes between the data B-channel and the analog device B-channel. All I-modems need a CSV/D B-channel over which to pass V.120, fax/modem, and, optionally, V.110 data. data communications A type of communications in which computers and terminals are able to exchange data over an electronic medium.
U.S. Robotics I-modem Command Reference data compression table A table of values assigned for each character during a call under data compression. Default values in the table are continually altered and built during each call: the longer the table, the more efÞcient throughput gained. If a destructive Break is sent during a call (see the &Y command), causing the modems to reset the compression tables, you can expect diminished throughput.
U.S. Robotics I-modem Command Reference data terminal equipment (DTE) The device that generates or is the Þnal destination of data. DCE See data communication equipment. D-channel In ISDN BRI, a 16-Kbps channel for call control signaling or for passing packet-mode (for example, X.25) data. In ISDN PRI, a 64-Kbps channel for call-control signaling or for passing packet-mode data. The ÒDÓ stands for Òdelta.
U.S. Robotics I-modem Command Reference digital signals Discrete, uniform signals. In this manual, the term refers to the binary digits 0 and 1. DIP switch DIP stands for dual in-line package. directory number (DN) The ISDN equivalent of an ordinary telephone number, except that often the area code is left off. See SPID. DMS-100 See Northern Telecom DMS-100. DN See directory number. DTE See data terminal equipment.
U.S. Robotics I-modem Command Reference duplex Indicates a communications channel capable of carrying signals in both directions. See half duplex, full duplex. E echo See local echo. EIA Electronic Industries Association, which deÞnes electronic standards in the United States. EIA-232 A technical speciÞcation published by the Electronic Industries Association that establishes mechanical and electrical interface requirements among computers, terminals, modems, and communication lines.
U.S. Robotics I-modem Command Reference equalization A compensation circuit designed into modems to counteract certain distortions introduced by the telephone channel. Two types are used: Þxed (compromise) equalizers and those that adapt to channel conditions. U.S. Robotics high-speed modems use adaptive equalization. error control Various techniques which check the reliability of characters (parity) or blocks of data. V.
U.S. Robotics I-modem Command Reference fax See facsimile. Fax mode The mode in which the fax modem is capable of sending and receiving Þles in a facsimile format. File Transfer Protocol (FTP) A TCP/IP application that allows users of an internet to send (put) and receive (get) Þles. Flash memory A form of memory that can be electrically erased and reprogrammed without the need to remove it from the circuit board.
U.S. Robotics I-modem Command Reference frame A data communications term for a block of data with header and trailer information attached. The added information usually includes a frame number, block size data, errorcheck codes, and Start/End indicators. FTP See File Transfer Protocol. full duplex Signal ßow in both directions at the same time. In microcomputer communications, may refer to the suppression of the online Local Echo. H half duplex Signal ßow in both directions, but only one way at a time.
U.S. Robotics I-modem Command Reference handshaking A sequence that two modems undertake while connecting to agree on the parameters of the conversation that will ensue. During handshaking, the modems negotiate the speed of the connection, whether error control and data compression will be used and in what form, and so forth. hardware ßow control A form of ßow control that uses electronic signals to start and stop the ßow of data. HDLC See High-Level Data Link Control.
U.S. Robotics I-modem Command Reference High-Speed Technology (HST) U.S. Robotics' proprietary signaling scheme, design, and error- control protocol for highspeed modems. HST incorporates trellis-coded modulation, for greater immunity from variable phone line conditions, and asym-metrical modulation for more efÞcient use of the phone channel at speeds of 4800 bps and above. HST also incorporates MNP-compatible error-control procedures adapted to asymmetrical modulation. HST See High-Speed Technology.
U.S. Robotics I-modem Command Reference Industry Standard Architecture (ISA) The most common type of computer expansion bus. Other types include Extended Industry Standard Architecture (EISA) and Microchannel Architecture (MCA). Integrated Services Digital Network (ISDN) An international standard for providing end-to-end digital service over the public telecommunications network.
U.S. Robotics I-modem Command Reference ITU-T International Telecommunication Union-Telecommunication sector (formerly referred to as CCITT). An international organization that deÞnes standards for tele-graphic and telephone equipment. For example, the Bell 212A standard for 1200 bps communication in North America is observed internationally as ITU-T V.22. For 2400 bps com-munication, most U.S. manufacturers observe V.22bis. J jumper A switch composed of pins and a shunt.
U.S. Robotics I-modem Command Reference L LAPD See Link Access Procedure for the D-channel. LAPM See Link Access Procedure for Modems. Link Access Procedure for the D-channel (LAPD) An error control protocol incorporated in ITU-T Recommendation I.440 and I.441. Link Access Procedure for Modems (LAPM) Link Access Procedure for Modems, an error control protocol incorporated in ITU-T Recommendation V.42.
U.S. Robotics I-modem Command Reference another system) the local echo is invoked through the ATE1 command. The command causes the modem to display typed commands. When the modem is online to another system, the local echo is invoked through the ATF0 command. This command causes the modem to display the data it transmits to the remote system. M MB Megabyte, or one thousand bytes. Microcom Networking Protocol (MNP) An asynchronous error-control protocol developed by Microcom, Inc.
U.S. Robotics I-modem Command Reference modem A device that transmits/receives computer data through a communications channel such as radio or telephone lines. The Courier is a telephone channel modem that modulates, or transforms, digital signals from a computer into the analog form that can be carried successfully on a phone line. It also demodulates signals received from the phone line back to digital signals before passing them to the receiving computer.
U.S. Robotics I-modem Command Reference NI-1 See National ISDN-1. NI-2 See National ISDN-2. NIUF See North American ISDN UsersÕ Forum. nonvolatile random access memory (NVRAM) User-programmable random access memory whose data is retained when modem power is turned off. Used in Courier modems to store a user-deÞned default conÞguration loaded into random access memory (RAM) at power on.
U.S. Robotics I-modem Command Reference Northern Telecom DMS-100 A make and model of central ofÞce switch. Before NI-1, AT&T and Northern Telecom implemented proprietary protocols to handle ISDN calls. ThatÕs why itÕs important to know whether an NT DMS-100 central ofÞce switch is using proprietary (often referred to as simply DMS-100) or NI-1 call control signaling. NT-1 Network Termination 1.
U.S. Robotics I-modem Command Reference online fallback A feature that allows high-speed error-control modems to monitor line quality and fall back to the next lower speed if line quality degrades. The modems fall forward as line quality improves. Online mode When the I-modem is in Online mode, it is connected over telephone lines with another device. originate mode A state in which the modem transmits at the predeÞned low frequency of the communications channel and receives at the high frequency.
U.S. Robotics I-modem Command Reference P parallel transmission The transfer of data characters using parallel electrical paths for each bit of the character, for example, 8 paths for 8-bit characters. Data is stored in computers in parallel form, but may be con-verted to serial form for certain operations. See serial transmission. parity An error-detection method that checks the validity of a transmitted character.
U.S. Robotics I-modem Command Reference Plug and Play ISA A variation of the standard ISA bus that attempts to automate the troublesome process of resolving the IRQ and COM port conßicts that can arise when new devices are installed in ISA-bus computers. point-to-point A circuit that connects two stations directly. PRI See Primary Rate Interface.
U.S. Robotics I-modem Command Reference protocol A system of rules and procedures governing communications between two or more devices. Protocols vary, but communi-cating devices must follow the same protocol in order to exchange data. The format of the data, readiness to receive or send, error detection and error correction are some of the opera-tions that may be deÞned in protocols. provisioning Another way of saying Òsetting up telephone lines.Ó R RAM See random access memory.
U.S. Robotics I-modem Command Reference rate adaption Also referred to as rate adaptation. V.120 and V.110 are rate adaption protocols: they allow devices that communicate at speeds of less than 64 Kbps to adapt their rates to 64 Kbps to Þll the entire B-channel. read-only memory (ROM) Permanent memory, not user-programmable. The Courier's factory settings are stored in ROM and can be read (loaded) into RAM as an operational conÞguration if DIP switch S10 is ON at power-on.
U.S. Robotics I-modem Command Reference remote echo A copy of the data received by the remote system, returned to the sending system and displayed on the screen. Remote echoing is a function of the remote system. result code Another way of saying Òstatus message.Ó The I-modem sends result codes to your terminal (for example, to indicate the status of a connection).
U.S. Robotics I-modem Command Reference S SDLC See Synchronous Data Link Control. S/T-interface The name given to the signaling interface between an NT-1 and a terminal adapter or an ISDN terminal. serial port A computer port that enables the transmission of data characters, one bit at a time, using a single electrical path. Also known as a communications port, or COM port. On IBM-compatible PCs, this is a port for asynchronous, serial data transmission and, in the case of modems, for data reception.
U.S. Robotics I-modem Command Reference Service ProÞle IdentiÞer (SPID) A unique number, similar to an ordinary 10-digit telephone number but with up to four digits appended, that is assigned to each device that connects to the ISDN. A SPID identiÞes the services to which you have subscribed and is required to be set correctly at your device. SPIDs apply only in North America. software ßow control A form of ßow control that uses XON and XOFF characters to start and stop the ßow of data.
U.S. Robotics I-modem Command Reference shunt A small, plastic-and-metal piece used to cover sections of pins on a jumper. The shunt interconnects certain pins which, depending on the way the shunt is placed, determine functions. SPID See Service ProÞle IdentiÞer. S-register An area of NVRAM that is used to store a setting. switch See central ofÞce switch.
U.S. Robotics I-modem Command Reference synchronous transmission A form of transmission in which blocks of data are sent at strictly timed intervals. Because the timing is uniform, no start or stop bits are required. Compare asynchronous transmission. Some mainframes only support synchronous communications unless their owners have installed a synchronous adapter and appropriate software. T TEI See Terminal Endpoint IdentiÞer.
U.S. Robotics I-modem Command Reference terminal adapter A device that connects another device that is not ISDN-ready to the ISDN S/T-interface. By converting EIA-232 or V.35 signals, for example, to S/T-interface signals, a terminal adapter makes a device that is not ISDN-ready able to communicate over the ISDN. Terminal Endpoint IdentiÞer (TEI) A one- or two-digit number that identiÞes a given connection with the central-ofÞce switch. TEIs may be dynamic or Þxed.
U.S. Robotics I-modem Command Reference throughput The amount of actual user data transmitted per second with-out the overhead of protocol information such as Start and Stop bits or frame headers and trailers. Compare with characters per second. transmission rate See bit rate. U UART See Universal Asynchronous Receiver/Transmitter. U-interface The name given to the signaling interface between the telephone companyÕs equipment and an NT-1.
U.S. Robotics I-modem Command Reference Universal Asynchronous Receiver/Transmitter (UART) A computer chip that controls the signaling that goes on through a computerÕs serial port. UTP (Unshielded Twisted Pair) Twisted insulated copper wires bundled into an unshielded cable, commonly used in telephone wiring systems. Grades of UTP include DTP (Datagrade Twisted Pair) and DIW (Distributed Inside Wire). V V.
U.S. Robotics I-modem Command Reference V.21 Fax An ITU-T standard for facsimile operations at 300 bps. U.S. Robotics or compatible fax devices then transmit or receive at higher speeds. V.21 An ITU-T standard for modem communications at 300 bps. Modems made in the United States or Canada follow the Bell 103 standard. However, the modem can be set to answer V.21 calls from overseas. V.
U.S. Robotics I-modem Command Reference V.23 An ITU-T standard for modem communications at 1200 bps with a 75 bps back channel. Used in the U.K. V.25 An ITU-T standard for modem communications. Among other things, V.25 speciÞes an answer tone different from the Bell answer tone. All U.S. Robotics modems can be set with the B0 command so that they use the V.25 2100 Hz tone when answering overseas calls. V.
U.S. Robotics I-modem Command Reference V.29 An ITU-T standard for facsimile operations that speciÞes modulation at 9600 bps, with fallback to 7200 bps. V.32 An ITU-T standard for modem communications at 9600 bps and 4800 bps. V.32 modems fall back to 4800 bps when line quality is impaired, and fall forward again to 9600 bps when line quality improves. V.32bis An ITU-T standard that extends the V.32 connection range: 4800, 7200, 9600, 12K, and 14.4 Kbps. V.
U.S. Robotics I-modem Command Reference V.34 An ITU-T standard that allows data rates as high as 33.6 Kbps. V.35 An ITU-T standard trunk interface between a device and a packet network, using signaling of at least 19200 bps. V.42 An ITU-T standard for modem communications that deÞnes a two-stage process of detection for LAPM error control. V.42bis An extension of ITU-T V.42 that deÞnes a speciÞc data compression scheme for use with V.42 error control. V.110 A rate-adaption protocol for the B-channel.
U.S. Robotics I-modem Command Reference V.120 An asynchronous rate-adaption protocol for the B-channel. V.120 is a frame-oriented protocol based on LAPD, and it employs statistical multiplexing techniques to Þll the 64-Kbps channel. Multiple data streams can be mapped to one 64-Kbps channel using V.120. V.Fast Class (V.FC) A proprietary modulation scheme developed by Rockwell International for data communication speeds up to 28.8 Kbps.
U.S. Robotics I-modem Command Reference X XMODEM The Þrst of a family of error-control software protocols used to transfer Þles between modems. These protocols are in the public domain and are available from many bulletin board services. XON/XOFF Standard ASCII control characters used to tell a device to stop/resume transmitting data. In most systems typing -S sends the XOFF character.
U.S. Robotics I-modem Command Reference Z ZMODEM An error-correcting File Transfer Protocol that is related to, but faster than, XMODEM or YMODEM.
