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3Com Corporation 3800 Golf Rd. Rolling Meadows, Illinois 60008 Copyright © 1999, 3Com Corporation. All rights reserved. No part of this documentation may be reproduced in any form or by any means or used to make any derivative work (such as translation, transformation, or adaptation) without written permission from 3Com Corporation.
CONTENTS ABOUT THIS GUIDE Introduction ........................................................................................ 1 Finding Specific Information in This Guide ............................................ 2 Conventions ........................................................................................ 2 Related Documentation ....................................................................... 3 Year 2000 Compliance ........................................................................
Setting up your ISP information .................................................1-16 Other Operating Systems ................................................................1-17 If You Are Using Windows 3.x ...................................................1-17 If You Are Using MS-DOS ...........................................................1-17 If You Are Using UNIX, Linux, or AIX ..........................................1-17 2 USING THE AT COMMAND SET Overview ......................................
Call Detection .................................................................................. 4-6 Caller ID Functions ........................................................................... 4-7 Service Types ............................................................................... 4-7 Applications of Caller ID Technology ............................................ 4-7 How the Business Modem Handles Caller ID ................................ 4-8 Presentation Formats ...........................
Controlling Link Speeds with &N and &U ..........................................8-4 Controlling Link Speeds ...............................................................8-4 Limiting the Highest Possible Connect Speed ...............................8-4 Limiting the Lowest Possible Connect Speed ................................8-5 Limiting a Range of Possible Connect Speeds ...............................8-5 &N and &U Command Values ......................................................
Software Flow Control .............................................................. 11-2 Received Data Flow Control ............................................................ 11-3 Transmit-Data Flow Control ............................................................ 11-5 12 HANDSHAKING, ERROR CONTROL, DATA COMPRESSION, AND THROUGHPUT Handshaking .................................................................................. 12-1 Selective Reject .....................................................
Digital Loopback Testing (AT&T3) ...............................................14-5 Remote Digital Loopback Testing (AT&T6, AT&T7) ......................14-6 Granting a Digital Loopback Test Request (AT&T4) .....................14-6 Canceling All Digital Loopback Test Requests (&T5) ....................14-6 Testing Using Keyboard Data (AT&T6) ........................................14-7 Testing Using a Built-in Test Pattern (AT&T7) ...............................
Getting New Operating Software .................................................. 16-2 Sending New Software to your modem .......................................... 16-2 If Your Modem Doesn’t Respond .................................................... 16-4 A S-REGISTERS Understanding Bit-Mapped S-Registers .............................................A-1 How bits are mapped to decimal values ............................................A-1 Converting Bits to Decimal Values ................................
Additional Specifications .............................................................. E-3 Serial Ports ................................................................................... E-3 The EIA-232 Interface .................................................................. E-4 Wiring a DB-25 to DB-9 Cable ..................................................... E-4 Minimum Requirements ............................................................... E-4 Flow Control Requirements .......................
ABOUT THIS GUIDE Introduction This guide is a command reference for the 3Com OfficeConnect 56K Business Modem. It includes information about AT commands, S-Registers and troubleshooting. If the information in the release notes shipped with your product differs from the information in this guide, follow the instructions in the release notes. Finding Specific Information in This Guide This table shows the location of specific information in this guide.
2 ABOUT THIS GUIDE Conventions Table 1 and Table 2 list conventions that are used throughout this guide.
Related Documentation 3 Table 2 Text Conventions (continued) Convention Description Words in italicized type Italics emphasize a point or denote new terms at the place where they are defined in the text. Words in bold-face type Bold text denotes key features. Related Documentation The 3Com OfficeConnect 56K Business Modem Installation Guide should be used for the installation of the Business Modem.
4 ABOUT THIS GUIDE
1 CONNECTING TO YOUR ISP This chapter contains information about configuring your modem for various operating systems. Windows 95/98 ■ Windows 95/98 ■ Windows NT 4.0 and Later ■ Macintosh ■ Other Operating Systems The first time you start Windows 95/98 after you’ve installed the modem, Windows 95/98 will auto-detect your modem. Since Windows 95/98 supports Plug and Play, most installations are trouble-free.
1-2 CHAPTER 1: CONNECTING TO YOUR ISP 3 When the following window appears, insert your Connections CD-ROM, change the default drive in Copy Manufacturer’s files from: to D:\ (or the correct path of your CD-ROM) and click OK to install the INF file. 4 Windows 95/98 displays a window asking you to choose your modem type from the list. Select the your modem from the list and click OK.
Windows 95/98 1-3 Step One: Determine if Dial-Up Networking is Installed 1 Click Start | Settings | Control Panel. 2 On the Control Panel, double-click on Network. The Network widow will appear. If Dial-Up Adapter Do this Is listed Go to the section "Installing TCP/IP Support" to install Dial-Up Networking. Is not listed Go to Step 3. 3 Return to the Control Panel and double-click on Add/Remove Programs to open the Add/Remove Programs Properties window. 4 Click Windows Setup tab.
1-4 CHAPTER 1: CONNECTING TO YOUR ISP 8 Insert your Windows 95/98 Setup diskette or CD-ROM when you are prompted, and Windows 95/98 installs Dial-Up Networking. Step Two: Installing Dial-Up TCP/IP Support 1 Click Start | Settings | Control Panel. 2 On the Control Panel, double-click on the Network to display the Network window: 3 Determine if the TCP/IP Dial-Up Adapter is installed: IF TCP/IP -> Dial-Up Adapter Do this Is not listed Click Add | Protocol | Microsoft | TCP/IP | OK.
Windows 95/98 1-5 9 On the My Connection window, click Server Type, and deselect the following: ■ Log on to Network ■ NetBEUI ■ IPX/SPX Compatible
1-6 CHAPTER 1: CONNECTING TO YOUR ISP 10 Click OK, and OK. If your ISP Do this Gives you a specific IP or Domain Name server addresses Go to Step Four: Customizing TCP/IP Settings Does not give you a Double-click on the icon you just created to dial your ISP. specific IP or Domain Name server addresses Step Four: Customizing the TCP/IP Settings Depending on the ISP you use, you may need to customize the TCP/IP settings.
Windows 95/98 1-7 5 Specify an IP address, if needed: If your ISP Do this Gives you a specific IP address Click Specify an IP address and enter the IP address provided by your ISP Does not give you a specific IP address Click Server assigned IP address 6 After you specify an IP Address, specify server assigned name server addresses, if needed: If your ISP Do this Gives you specific name server addresses Click Specify name server addresses and enter the server address(es) provided by your ISP Doe
1-8 CHAPTER 1: CONNECTING TO YOUR ISP 7 Double-click your New Connection icon to connect! Windows NT 4.0 and Later TCP/IP is the main protocol used to transfer data via the Internet. To use TCP/IP with Windows NT, you must connect to your ISP using a PPP or SLIP connection. Each ISP has different requirements. Before using this chapter to configure Windows NT to access your ISP, contact your ISP to determine if they have special instructions for Windows NT users.
Windows NT 4.0 and Later What you need Configuring Your modem 1-9 Before you begin, obtain the following information: ■ Does your ISP have a SLIP or PPP account? ■ Your ISP’s telephone number ■ Does your ISP supply a static or dynamic IP address? ■ Your ISP's primary and secondary DNS servers ■ INF file for Windows NT Since Windows NT is not Plug and Play compliant, it is necessary to install the modem in Modem Properties. Your modem should already be installed.
1-10 CHAPTER 1: CONNECTING TO YOUR ISP 8 Click Network. 9 Select the protocols required to dial in and out with your Business Modem. 10 Set Encryption Settings to Allow any authentication including clear text. 11 Click Continue to complete RAS setup. Determining if TCP/IP is installed TCP/IP must be installed before you can access the Internet. Although this is a standard configuration, double-check to make sure TCP/IP is installed.
Windows NT 4.0 and Later 1-11 7 Select Enable software compression. 8 Specify an IP address by clicking TCP/IP settings.
1-12 CHAPTER 1: CONNECTING TO YOUR ISP Troubleshooting RAS RAS is significantly easier to troubleshoot then Win95 Dial-Up Networking, there are a finite number of problems that one runs into on a daily basis, and the majority of these are caused by misconfiguration. Most connection problems can be solved by following these steps: ■ In the Basic tab, Make sure that the phone book entry settings are correct.
Macintosh System Configuration 1-13 Also, if you aren’t using AppleTalk® Remote Access (ARA), set AppleTalk to Inactive (in Chooser). The modem initialization string should be AT&F1&D0. For instructions about how to set up your Macintosh communications software package, see the software installation instructions that came with the software.
1-14 CHAPTER 1: CONNECTING TO YOUR ISP the script receives an OK back from the modem and/or the system responds with a proper speed. Configuring Open Transport PPP Selecting the correct modem 1 Go to Apple Menu | Control Panels | Modem. 2 In the Modems Window, choose the port that your modem is connected to in the Connect via drop down box. 3 Select the correct modem, in the Modem drop down box.
Macintosh 1-15 Selecting the correct TCP/IP settings 1 Go to Apple Menu | Control Panel | TCP/IP. 2 In the TCP/IP window, select PPP in the Connect via drop down box. 3 Set the Configure drop down box to Using PPP Server. 4 Type in your internet service providers Domain Name Server Address(DNS) numbers in the Name server addr box. 5 Leave the other fields empty.
1-16 CHAPTER 1: CONNECTING TO YOUR ISP Setting up your ISP information 1 Go to Apple Menu | Control Panels | PPP. 2 In the PPP window, select Registered User. 3 Type in your Internet Service providers login name and your password in the name and password boxes. 4 Put the phone number that you dial to connect to your internet provider in the number box.
Other Operating Systems Other Operating Systems If You Are Using Windows 3.x 1-17 This sections explains how to configure your modem for: ■ Windows 3.x ■ MS-DOS ■ UNIX, Linux, or AIX Windows 3.x comes with a built-in communications software package, Windows Terminal. You can use Windows Terminal to test your modem or you can install the communications software package that is included on the Connections CD-ROM.
1-18 CHAPTER 1: CONNECTING TO YOUR ISP
2 USING THE AT COMMAND SET This chapter includes information about Overview ■ Basic AT commands ■ Using S-Registers ■ Understanding bit-mapped S-Registers You can use AT commands to change your modem settings at any time. To send AT commands to your modem, you need to put your communications software in Terminal Mode. In terminal mode, what you type is sent directly to the modem.
2-2 CHAPTER 2: USING THE AT COMMAND SET AT&K3X2DT5551234 AT Attention; a command follows. &K3 Disable MNP5 data compression; use only V.42 bis compression. X2 Use the X2 result code subset. DT Dial the following number using tone dialing. Hyphens and parentheses add to the count of 56 characters but, spaces do not. Basic AT commands The command AT informs the modem that a command is coming. AT must precede all commands except A/, A> and +++.
Using S-Registers Displaying S-Register settings 2-3 You can display S-Registers in a variety of ways. See the table below for more information. To display Command Contents of ONE S-Register ATSr?, where r is the register’s number S-Register settings in the NVRAM templates ATI5 S-Register settings in RAM (the current configuration) ATI4 Example: Sending ATS0?, displays the contents or setting for S-Register 0.
2-4 CHAPTER 2: USING THE AT COMMAND SET Getting a list of S-Registers To display Command A list of S-Registers ATS$ In order to issue this command, you must be in Terminal Mode. See Appendix A, S-Registers for a complete list of S-Registers. Understanding bit-mapped S-Registers A bit-mapped S-Register uses one number to describe a collection of settings. Bit-mapping allows us to pack a lot of information in a small space. Bit-mapped registers are in the form of Sr.
3 MODES OF OPERATION This chapter contains information about Command and Online Modes ■ Command and Online Modes ■ Controlling Local Echo ■ Data and Fax Modes If you want to Set the modem to Use this command Control the modem using AT Command Mode commands. +++ (Escape Code) Your modem set to revert to Command Mode when the Escape Code (+++) is used. ATS14.0=0 Your modem to Disconnect when the Escape Code (+++) is used. ATS14.
3-2 CHAPTER 3: MODES OF OPERATION Entering Online Command Mode When the modem is in Online Mode, the only command it recognizes is an escape code, or +++. Revert to Command Mode without losing connections by sending ATS14.0=0 to the modem before establishing your connection. 5 Wait one second after sending the last item of data 6 Type +++ 7 Wait for OK to appear before typing any data You can change the characters used to revert to Command Mode or the wait time by resetting Register S2 or S12.
Controlling Local Echo Controlling Local Echo Command-Mode Local Echo 3-3 There are two local echo settings, one for Command Mode and one for Online Mode. You can configure your modem to display the commands you type on screen by using the ATEn command . If you want the commands you type to Command NOT appear on screen (Command Mode echo OFF) ATE0 Appear on your screen (Command Mode echo ON) ATE1 Although you cannot see the command when you set ATE0, the modem is receiving them.
3-4 CHAPTER 3: MODES OF OPERATION Data and Fax Modes Once you are in Command Mode, you can initialize the modem in Data or Fax mode. Fax operations require facsimile-compatible communications software that can send or receive Group III faxes. Follow the instructions in your fax software manual. The modems default operating mode is Data Mode. Most fax software automatically switches the device to Fax mode when you run the program, and resets the device to Data mode when you exit the program .
Data and Fax Modes 3-5 If you are not sure whether your modem is in Data or Fax mode, use the AT+FCLASS? command . If the modem returns a value of This indicates 0 Data Mode 1 Class 1 Fax Mode 2.0 Class 2.0 Fax Mode. Whenever the modem is reset using the ATZ command or by turning the power off and then on, it will reset to Data Mode.
3-6 CHAPTER 3: MODES OF OPERATION
DIALING, ANSWERING, AND HANGING UP 4 This chapter explains how to use basic AT commands for: Dialing ■ Dialing ■ Carrier loss redial ■ Answering calls ■ Making International calls ■ Call detection ■ Caller ID functions ■ Distinctive Ring support You can use your modem to dial the specified phone number and execute dial options by using the following commands. Dial options For your modem to Command Dial the specified phone number and execute dial options (DO NOT use spaces or dashes).
4-2 CHAPTER 4: DIALING, ANSWERING, AND HANGING UP For your modem to Command Wait for an answer (with X3 or higher). ATD@ Some online services answer the phone and return a tape-recorded request for information before processing transactions. Use the AT@ command to tell the modem to detect at least one ring, wait for five seconds of silence at the other end of the call, and then continue. To use the AT@ command, set the modem to X3, X4 or X7.
Carrier Loss Redial For your modem to Command Dial a number, wait 60 seconds for a connection, and then hang up. Wait two seconds, then redial. Make a maximum of 10 attempts. > 4-3 To stop the repeating, press any key during the pause between dial attempts. If you press any key while the modem is dialing, that dial attempt is canceled but the cycle will continue Dial the last-dialed number and repeat it just as the > command does. Also can be used to repeat any command.
4-4 CHAPTER 4: DIALING, ANSWERING, AND HANGING UP Answering Calls Your modem can be configured to answer calls. By default, your Business Modem will not automatically answers calls. Force Answer Mode For your modem to Command Go through the answer sequence when it hasn't received an incoming call ATA Or Manually answer a call Auto Answer You can set your modem to Auto Answer using the ATS0 command .
Making International calls Hanging up 4-5 If you want to end a connection with a remote device do the following: 1 Enter Online Command Mode by typing +++ 2 Wait 1 second 3 Type ATH Making International calls You can use the ATBn, AT&Gn and ATPn commands for making analog international calls above 1200 bps. Handshaking options The ATBn command controls the handshake options. . If you want your modem Command To answer all V.
4-6 CHAPTER 4: DIALING, ANSWERING, AND HANGING UP Guard tone The AT&Gn command only applies to analog overseas calls at 2400 or 1200 bps. To set your modem for Command Required in these countries No guard tone AT&G0 (Default) United States and Canada 550-Hz guard tone AT&G1 Some European countries 1800-Hz guard tone AT&G2 The U.K. and some Commonwealth countries If you set &G2 you must also send ATB0 to the modem. This setting allows the Business Modem to answer all calls from overseas.
Caller ID Functions Caller ID Functions 4-7 Caller ID is a service provided by local telephone companies. When you subscribe to caller ID, your phone company begins providing you real-time information about incoming calls. The caller ID signal includes the date and time of the call, the phone number of the calling device, and, optionally, the name of the calling party. The signal is sent between the first and second rings and must be decoded and displayed by a device connected to your phone line.
4-8 CHAPTER 4: DIALING, ANSWERING, AND HANGING UP How the Business Modem Handles Caller ID When the modem receives the caller ID signal, it stores the information in memory. You can access the information at any time by sending ATI15 to the modem. ati15 3Com OfficeConnect 56K Business Modem CID Status… 80 1E 01 08 31 30 31 35 32 30 33 38 02 0A 37 30 38 35 35 35 30 30 30 31 07 0C 55 2E 53 2E 52 4F 42 4F 54 49 43 53 22 DATE = 1015 TIME = 2038 NMBR = 8475550001 NAME = U.S.
Caller ID Functions Presentation Formats 4-9 The Business Modem sends the caller ID information to your computer formatted or unformatted. Formatted presentation is a translation of the caller ID signal into ASCII text. Unformatted presentation is a hexadecimal representation of the caller ID signal. An Example of Formatted caller ID presentation: RING DATE = 1015 TIME = 2038 NMBR = 8475550001 NAME = U.S.
4-10 CHAPTER 4: DIALING, ANSWERING, AND HANGING UP Caller ID Action Command Enable Caller ID with formatted output and name AT#CID=3 suppressed References Enable Caller ID but do not transmit the information to your computer—retain it in the Business Modem’s memory AT#CID=4 Display the current caller ID setting. AT#CID? Display the Caller ID settings that are available AT#CID=? For more information about Calling Number Delivery (CND), refer to Bellcore documents TR-TSY-000030 and TR-TSY-000031.
Distinctive Ring Support 4-11 There are four ring patterns in common use: Ring Description A 1.2 to 2.0 seconds on, 4.0 seconds off. B 0.8 second on, 0.4 second off, 0.8 second on, 4.0 seconds off. C 0.4 second on, 0.2 second off, 0.4 second on, 0.2 second off, 0.8 second on, 4.0 seconds off. D 0.3 second on, 0.2 second off, 1.0 second on, 0.2 second off, 0.3 second on, 4.0 seconds off. These are graphical depictions of each ring pattern.
4-12 CHAPTER 4: DIALING, ANSWERING, AND HANGING UP When a call comes in with a ring type A or D, the Business Modem will send the result code RING A or RING D, respectively. The Business Modem will ignore other ring types. If S70 is set to 0 (the default) the Business Modem detects ring types A and B, sending the result code RING for either ring type. This function is identical to that of other 3Com modems that do not support distinctive ring.
5 WORKING WITH MEMORY This chapter contains information about: ■ Saving a phone number to NVRAM ■ Working with Flash Memory You can upgrade the software held in Flash memory by performing a software download. See Chapter 3, Upgrading your Software, for more information about performing a software downloads. Overview Business Modems contain three types of memory that you can interact with: random access memory (RAM), nonvolatile random access memory (NVRAM), and Flash memory.
5-2 CHAPTER 5: WORKING WITH MEMORY Example: Sending ATI5 will display NVRAM settings on your screen. To see a complete listing of the permanent settings stored in Flash memory see Appendix C, Flow Control Templates. Working with RAM and NVRAM You can change any setting just for the current session. For example setting your Business Modem to AT&N8 will only allow a connection to a remote devices at a rate of 14400 bps until the modem is reset.
Working with Flash Memory 5-3 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. Type: AT&M0DS2 The AT&Zn=s command functions differently when Dial Security is enabled. See Chapter 11, Dial Security, for more information.
5-4 CHAPTER 5: WORKING WITH MEMORY All of the settings in each template are given in Appendix C, Flow Control Templates. For more information about hardware and software flow control, See Chapter 12, Flow Control. Saving ROM Templates to NVRAM Default Settings To save one of the three ROM templates to NVRAM and have it serve as the reset default, enter AT&Fn&W When the Business Modem is turned on it loads the settings stored in NVRAM. By default, these settings are that same as the &F1 template.
6 CONTROLLING RESULT CODE DISPLAYS This chapter contains information about: Result Code Display Commands ■ Result Code Display commands ■ Additional Result Code subsets The commands listed below control whether result codes are displayed, and in what format they are displayed . If you want the modem to Command Display result codes. ATQ0 NOT display result codes. ATQ1 NOT display result codes while in Answer mode. See Chapter 4, Modes of Operation, for a description of modes.
6-2 CHAPTER 6: CONTROLLING RESULT CODE DISPLAYS Additional Result Code Subsets ARQ (Automatic Repeat Request) is used in this manual to denote calls that use error control. . For your modem to Command Display only connection rate. AT&A0 Display connection rate and ARQ result codes. AT&A1 Display connection rate, ARQ result code, and protocol information (V32, VFC, V34, or x2/v.90). If your software cannot handle the added protocol information, select &A1 or &A0.
7 CONTROLLING EIA-232 SIGNALING This chapter contains information about configuring the EIA-2321 signalling between your computer and modem: Data Terminal Ready ■ Data Terminal Ready ■ Data Set Ready ■ Carrier Detect Your computer sends a Data Terminal Ready (DTR) signal to the Business Modem when it is ready to send and receive data. The &Dn command tells the modem how to respond to the DTR signal. For your modem to Command Ignore the state of DTR and act as if DTR is always present.
7-2 CHAPTER 7: CONTROLLING EIA-232 SIGNALING Data Set Ready Under normal conditions, the Business Modem sends a Data Set Ready (DSR) signal to your computer when it is ready to send and receive data. CAUTION: Do not change the default setting of &S0 unless you know that your installation requires a different setting. Few Windows communications programs, if any, will require the Business Modem to control DSR (&S1). Use the following command to control how the modem sends the DSR signal.
Carrier Detect Carrier Detect 7-3 Carrier means there is communication with the device on the other end of the connection. Under normal conditions, the Business Modem sends a Carrier Detect (CD) signal in response to establishing a connection with another modem. You can use the AT&Cn command to control how the Business Modem sends the CD signal. . For your modem to Command Have CD always ON.
7-4 CHAPTER 7: CONTROLLING EIA-232 SIGNALING
8 CONTROLLING DATA RATES This chapter contains information about ■ Serial port rates ■ Connection rates ■ Controlling Link Speeds with &N and &U ■ Setting DTE Rate to 230 Kbps Overview You can set the Business Modem to use fixed or variable serial port rates and fixed or variable connection rates. Serial port rates pertain to data transferred between your computer and the Business Modem.
8-2 CHAPTER 8: CONTROLLING DATA RATES Your software may use terms such as locked serial port (fixed rate) or autobaud (variable rate). To allow your modem Set the serial port rate as Command To change its serial port rate to match the Variable connection rate. AT&B0 To always communicate with an attached Fixed device at the rate at which you have set the terminal or software, regardless of the connection rate.
Connection Rates Connection Rates 8-3 You can set the Business Modem to a fixed or variable connection rate for data calls. Set a variable rate to have the Business Modem negotiate with the remote device for the highest possible connection rate. Set a fixed rate to connect only at a specified rate. You might use a fixed rate to filter calls for security or other reasons. To allow your modem to Set connection rate as Command Negotiate for the highest possible rate.
8-4 CHAPTER 8: CONTROLLING DATA RATES Controlling Link Speeds with &N and &U Controlling Link Speeds You can use the &N and &U commands to control link speeds. Use the following table to determine how to use &N and &U commands: To limit the Use Highest possible connect speed AT&N Lowest possible connect speed AT&U Range of possible connect speeds AT&N and AT&U The default values for &N and &U are 0. If you change these values, you will limit the speeds at which you can connect.
Controlling Link Speeds with &N and &U Limiting the Lowest Possible Connect Speed 8-5 The &U command allows you to limit the lowest possible connect speed. If a remote modem attempts to connect to your Business Modem at a speed lower than &U, your Business Modem will not allow it to connect. To limit the Use this command Where x is Lowest possible connect speed AT&U=x A value from 0 to 32 See the table in the section &N and &U Command Values for connect speed values.
8-6 CHAPTER 8: CONTROLLING DATA RATES &N and &U Command Values Use the following table for a complete list of &N and &U link speeds and their associated indexes: Link Speed Index Highest 0 300 1 1200 2 2400 3 4800 4 7200 5 9600 6 12000 7 14400 8 16800 9 19200 10 21600 11 24000 12 26400 13 28800 14 31200 15 33600 16 28000 17 29333 18 30666 19 32000 20 33333 21 34666 22 36000 23 37333 24 38666 25 40000 26 41333 27 42666 28 44000 29 45333 30
Setting DTE Rate to 230 Kbps Setting DTE Rate to 230 Kbps Link Speed Index 46666 31 48000 32 49333 33 50666 34 52000 35 53333 36 54666 37 56000 38 57333 39 8-7 The DTE rate of your Business Modem has been increased to 230 kbps to enhance throughput. This command is only supported on Business Modems attached to high speed serial cards.
8-8 CHAPTER 8: CONTROLLING DATA RATES
9 ACCESSING AND CONFIGURING THE BUSINESS MODEM REMOTELY This chapter contains information about: Overview ■ Setting up remote access ■ Accessing the host ■ Quitting a remote access session You can set up the Business Modem so other devices can view or change its configuration remotely. You should be familiar with these terms before you continue: Local The device that is directly connected to the computer you are using. Remote The device at the other end of a telephone connection.
9-2 CHAPTER 9: ACCESSING AND CONFIGURING THE BUSINESS MODEM REMOTELY 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. Example: Sending ATS41=1&W allows for 1 log-in attempt by a remote user. 3 Set one or two remote-access passwords.
Accessing the Host Other Remote-Access Commands 9-3 The table below is a list of remote-access configuration commands. For your modem to Command Display a view-only password AT%P0? Display a view-and-change password AT%P1? Erase a view-only password AT%P0= Erase a view-and-change password AT%P1= Disable remote access entirely ATS41=0 Example: Sending AT%P1= will erase the view and change password.
9-4 CHAPTER 9: ACCESSING AND CONFIGURING THE BUSINESS MODEM REMOTELY 4 You should see a display similar to this: 3Com OfficeConnect 56K Business Modem Remote Access Session Serial Number 000000A000000001 Password (Ctrl-C to cancel)? There is a 3-minute time limit for entering the password. If the number of unsuccessful log-in attempts exceeds the set limit, the host device returns online and refuses any further log-in attempts during the remainder of the connection.
Accessing the Host 9-5 Depending on your access privileges, you can use the regular set of Business Modem AT commands. If you have this access privilege You can use View-only Any of the inquiry (ATI) commands View and Configure Any of the Business Modem commands, except those that cannot be used while online (for example, ATD or ATA). You can also use remote configuration commands. See the next section for examples.
9-6 CHAPTER 9: ACCESSING AND CONFIGURING THE BUSINESS MODEM REMOTELY You can use the AT%Fn command to control the data format. To change the data format to Command No Parity (8 data bits) AT%F0 Mark parity (7 data bits) AT%F1 Odd Parity (7 data bits) AT%F2 Even parity (7 data bits) AT%F3 You can use the AT%Cn command to control whether and when to apply changes to the configuration For your modem to Command Defer configuration changes to when the call ends.
Quitting a Remote-Access Session 9-7 If you restore the original configuration using the AT%C1 command, the first prompt is restored, assuring you the original configuration is intact. 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 you’ve entered the password, you can quit by sending one of these commands: To end the remote-access session Command And keep the connection.
9-8 CHAPTER 9: ACCESSING AND CONFIGURING THE BUSINESS MODEM REMOTELY
10 DIAL SECURITY This chapter contains information about: Overview ■ Setting up Dial Security ■ Maintaining security accounts ■ What the guest user needs to do ■ Configuring dial security remotely Dial Security is designed to protect networks and data centers from unauthorized access. You should be familiar with these terms before you continue: Local The device that is directly connected to the computer you are using. Remote The device at the other end of a telephone connection.
10-2 CHAPTER 10: DIAL SECURITY 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. 1 Set up an account for yourself. Use any of the 40 available accounts (numbered 0-39) for your account.
Setting up Dial Security Dialback options 10-3 You can set the Business Modem to automatically dialback a certain number after a client modem dials in. Count your commas! There should always be four commas in the %A command.Do not insert spaces between commas or between fields and commas. Spaces will invalidate the command. To make the host Business Command Modem Example Hang up and then dial back a AT%A0=password,y ,y,n,1 area code guest device at a specified and phone number number.
10-4 CHAPTER 10: DIAL SECURITY will be locked out of the Business Modem’s dial security features. You will need to restore the factory defaults. This will erase ALL passwords and you will have to reconfigure all your accounts. 3 Set up guest-user accounts. Use the AT%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. Refer to the figure in step 1 regarding information about formatting the AT%An command.
Setting up Dial Security Autopass Prompting 10-5 Autopass is the default form of password protection. Autopass automates the process of logging in to the host modem, but it requires the guest and host devices to be Business Modems. When a guest device attempts an Autopass connection, the guest includes its password in its V.42 error-control request. The host modem checks all the enabled passwords in its security accounts for a match.
10-6 CHAPTER 10: DIAL SECURITY 6 Enable Dial Security. WARNING: Before you enable Dial Security, you must set up an administrative account and password. See Steps 1 & 2. For your modem to enable Command Autopass Dial Security ATS53.0=1 Dial Security with Password Prompting (this also enables Autopass) ATS53.0=1.
Maintaining Security Accounts Maintaining Security Accounts 10-7 Once the administrative password is set and Dial Security is enabled, the administrator is the only one who can access account information. You can use the AT%S= and AT%E= commands to change and modify account information. For your modem to Command Access accounts by disabling local security AT%S=administrative password View account information, once access has been ATI10 granted.
10-8 CHAPTER 10: DIAL SECURITY 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 host’s administrator. The password is case-sensitive, so be sure to copy it correctly.
Configuring Dial Security Remotely 10-9 3 If Dialback is enabled at the host Business Modem’s site, set your modem to answer the host Business Modem when it dials back. For your modem to be set Command To answer the Dialback call ATS0=1 4 Call the host. 5 After the call ends you can disable Auto Answer. Configuring Dial Security Remotely For your modem to Command Disable Auto Answer ATS0=0 The host administrator can configure the host’s security settings remotely.
10-10 CHAPTER 10: DIAL SECURITY 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 ATI10 screen and all Dial Security accounts.
11 FLOW CONTROL This chapter contains information about Overview ■ Hardware and software flow control ■ Received-data flow control ■ Transmit-data flow control The Business Modem has two buffers, one for data transmitted from your computer, and one for data received from the phone line. Flow control provides a system for stopping and starting transmission depending on how full the buffers are. Flow Control’s purpose is to prevent overfilling the buffers, which may cause data to be lost.
11-2 CHAPTER 11: FLOW CONTROL Hardware and Software Flow Control There are two kinds of flow control: hardware and software. Business Modems support both, but your computer and communications software must also support the kind of flow control you choose. Hardware Flow Control Business Modems implement hardware flow control by detecting that a buffer is 90% full and then interrupting the Clear to Send (CTS) signal to stop the flow of data.
Received Data Flow Control Received Data Flow Control 11-3 Flow control settings are controlled by the AT&Rn and AT&In commands. The default settings are &R2&I0. Use the following table for more information about setting the flow control. For your modem to Command Pause before sending CTS signal after receiving the Request to Send (RTS). AT&R0 Ignore the RTS signal. AT&R1 &R1 is required if your computer or software does not support RTS Enable hardware flow control.
11-4 CHAPTER 11: FLOW CONTROL For your modem to Command Enable Hewlett Packard-Terminal mode. Applies only to Business Modems attached to terminals in an HP system that uses the ENQ/ACK protocol. Use in ARQ mode only. AT&I4 Enable flow control when the connection is not under error control. For this to work, the remote device must also have AT&I5 capability. In ARQ mode, a Business Modem set to AT&I5 operates the same as it does when set to &I2.
Transmit-Data Flow Control Transmit-Data Flow Control 11-5 This type of flow control is for data transmitted to the Business Modem by its attached computer. For your modem to Command Disable transmit data flow control AT&H0 Enable Hardware flow control. AT&H1 Requires that your computer and software support Clear to Send (CTS) at the EIA-232 interface. Enable Software flow control. AT&H2 Requires that your software support XON/XOFF signaling. Use both hardware and software flow control.
11-6 CHAPTER 11: FLOW CONTROL
12 HANDSHAKING, ERROR CONTROL, DATA COMPRESSION, AND THROUGHPUT This chapter contains information about: Handshaking ■ Handshaking ■ Selective Reject ■ V.90 Capabilities ■ Error Control ■ Data compression ■ Getting maximum throughput With each call, Business Modems go through a link negotiation process with the remote device. Another name for the negotiation process is "handshaking." Business Modems default to V.
12-2 CHAPTER 12: HANDSHAKING, ERROR CONTROL, DATA COMPRESSION, AND THROUGHPUT Selective Reject is an optional part of the ITU-T V.42 (LAPM) standard. For your modem to Command Enable Selective Reject ATS51.6=0 (Default) Disable Selective Reject ATS51.6=1 Attaining Speeds Above 28.8 Kbps V.34 connections at 21.6, 24, and 26.4 Kbps are common. To get connections of 28.8, 31.2, and 33.6 Kbps, line quality must be pristine end-to-end. In addition, 31.2 and 33.
V.90 Capabilities 12-3 If you enable the V.8 call indicate tone, expect to hear a sound like a fast ringing signal while the call is being connected. V.34 If the remote device has V.34 capability, Business Modem use a line probing technique to determine the highest speed possible under current line conditions, then they complete the connection. If the remote device does not have V.
12-4 CHAPTER 12: HANDSHAKING, ERROR CONTROL, DATA COMPRESSION, AND THROUGHPUT If the remote device has V.FC capability, the Business 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.FC capability, the Business Modem listens to the device's answer tones to identify what standard rate the remote analog device is operating at, and adjusts to that rate.
Error Control Lower-speed V. Protocols 12-5 Older, lower-speed "V." protocols do not employ line probing. Instead they use predefined answer tones to specify or identify speed capabilities. These protocols define the following maximum speeds: ■ 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.
12-6 CHAPTER 12: HANDSHAKING, ERROR CONTROL, DATA COMPRESSION, AND THROUGHPUT .
Error Control V.42 Error Control 12-7 The Business Modem first tries for a V.42 connection, then an MNP connection. The following information is based on the Business Modem's setting of &M4. This international standard includes a two-stage hand-shaking process: ■ A Detection phase that is based on an exchange of predefined characters.
12-8 CHAPTER 12: HANDSHAKING, ERROR CONTROL, DATA COMPRESSION, AND THROUGHPUT Data Compression Business Modems employ different data compression techniques during data connections. For the modem to Command Disable data compression AT&K0 Auto-enable/disable data compression. The Business Modem enables compression if the serial port rate is fixed (&B1) and disables compression if the serial port rate follows the connection rate (&B0).
Getting Maximum Throughput 12-9 Possible dictionary sizes: Bits Entries 9 512 10 1024 11 2048 Your modem uses 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 dictionary. ■ Maximum string length of each entry. As the dictionary fills, your modem deletes the oldest unused strings. V.42bis compression is more efficient than MNP5 compression, in part because it dynamically deletes entries that are no longer used.
12-10 CHAPTER 12: HANDSHAKING, ERROR CONTROL, DATA COMPRESSION, AND THROUGHPUT Installations with specialized software may want to enable a fixed serial port rate for ARQ calls and a variable serial port rate for non-ARQ calls. See the &B2 command in Appendix B, Alphabetic Command Summary. ■ The call is under data compression. ■ The data is made up of text files rather than binary files such as .EXE or .ZIP files.
Getting Maximum Throughput 12-11 Overhead is minimal with ZMODEM, resulting in throughput that is almost equal to that obtained with no file-transfer protocol. ZMODEM should also be used for non-ARQ connections. Leave the Business Modem at its &M4 and &K1 settings for both error control and data compression. YMODEM-G is another good choice, but never use it unless both the local and remote devices are using error control: if YMODEM-G detects an error, it aborts the transfer.
12-12 CHAPTER 12: HANDSHAKING, ERROR CONTROL, DATA COMPRESSION, AND THROUGHPUT
13 DISPLAYING QUERYING AND HELP SCREENS This chapter contains information about: ■ Querying ■ Displaying help To view screen captures of the help screens in the following chapter, see Appendix B, Alphabetic Command Summary. Overview The Business Modem can display information such as the current settings, product code, and call duration.
13-2 CHAPTER 13: DISPLAYING QUERYING AND HELP SCREENS For your modem to Command ATI2 Perform a test of the modem’s 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 Business Modem appears to be malfunctioning. Display the Business Modem’s banner, or product title. ATI3 Display the Business Modem’s current configuration.
Displaying Help Displaying Help 13-3 The Business Modem provides six help, or command summary, screens: basic AT command set, ampersand (&) command set, percent (%) command set, percent (%) command set, dial command options (D), S-Registers (S), and the octothorpe (#) command set.
13-4 CHAPTER 13: DISPLAYING QUERYING AND HELP SCREENS
14 TESTING THE CONNECTION This chapter contains information about: Overview ■ Testing the Business Modem using AT&Tn ■ Testing the Business Modem using S-Register 16 Your 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. Testing is done by sending the AT&Tn command or by setting Register S16. Only one test can be performed at a given time.
14-2 CHAPTER 14: TESTING THE CONNECTION Testing the Business Modem using AT&Tn To perform digital loopback and remote digital loopback testing use the AT&Tn command. You can type in your own data during testing or use the modem's internal test pattern and error detector. See the following sections for more detailed information about each AT&Tn command. For your modem to Command End testing AT&T0 Enter analog loopback (AL) mode and send a CONNECT AT&T1 message. Data is shown on your screen.
Testing the Business Modem using AT&Tn Analog Loopback Testing 14-3 Local loopback testing checks the operation of the Business Modem transmitter and receiver. Using AT&T1 1 Send AT&M0&N3S14.0=0 to prepare the modem for testing. This command disables error control, fixes the connection rate at 2400 bps, and makes the modem return to command mode when you type +++. 2 Send AT&T1 to the modem so it enters analog loopback mode. The MR status light flashes.
14-4 CHAPTER 14: TESTING THE CONNECTION If you use the S18 test timer, but in the process of testing you issue an ATZ command, S18 resets to zero and the timer is disabled. You cannot store a value for S18 in NVRAM; its power-on and reset default is always zero. Using AT&T8 This analog loopback option causes the Business Modem to send an internal test pattern to its transmitter and loop it back to the receiver.
Testing the Business Modem using AT&Tn Digital Loopback Testing (AT&T3) 14-5 This test can help you locate a problem with a remote device or with the telephone line. The figure below shows the data flow during Digital Loopback (DL) testing. 1 Send the command AT&M0&N3S14.0=0 to the modem to prepare for testing.
14-6 CHAPTER 14: TESTING THE CONNECTION Remote Digital Loopback Testing (AT&T6, AT&T7) The remote digital loopback test, verifies the condition of both devices and of the phone line. Data flow is shown in the figure below. 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.
Testing the Business Modem using AT&Tn 14-7 Testing Using Keyboard Data (AT&T6) 1 Send AT&M0&N3S14.0=0 to prepare the Business Modem for testing. This command disables error control, fixes the connection rate at 2400 bps, and makes the Business Modem return to command mode when you type the escape code (+++). 2 Establish a connection with the remote device. 3 If you haven't already done so, arrange with the remote user to cooperate with the test.
14-8 CHAPTER 14: TESTING THE CONNECTION Testing Using a Built-in Test Pattern (AT&T7) This test option causes the modem to perform a remote digital loopback test by sending a built-in test pattern. An internal error detector counts any errors and, when the test is ended, sends the number of errors or 000 (no errors) to the screen. Follow the steps below. However, you don't need to type anything during this test. The modem sends only its final error count to your screen. 1 Send AT&M0&N3S14.
Testing the Business Modem using S-Resister 16 Testing the Business Modem using S-Resister 16 14-9 Register S16 is a bit-mapped register (See Appendix A, S-Registers, for instructions for setting bit-mapped registers). For your modem to use Use one of these command Remote digital loopback with built-in test pattern ATS16=4 or ATS16.2=1 Remote digital loopback using keyboard data ATS16=8 or ATS16.3=1 Earlier modems require bit 3 to be enabled to grant digital loopback testing to a remote device.
14-10 CHAPTER 14: TESTING THE CONNECTION Testing Using Keyboard Data (ATS16=8) 1 Send AT&M0&N3S14.0=0 to prepare the Business Modem for testing. This command disables error control, fixes the connection rate at 2400 bps, and makes the Business Modem return to command mode when you type the escape code (+++). 2 Establish a connection with the remote device. 3 If you haven't already done so, arrange with the remote user to cooperate with the test.
Testing the Business Modem using S-Resister 16 14-11 Testing Using a Built-in Test Pattern (ATS16=4) The test pattern is available at all speeds. At 300 bps, the Business Modem's serial port rate must be fixed (&B1) and the link rate fixed at 300 bps (&N1). At rates over 9600 bps, just set the Business Modem for a fixed serial port rate (&B1). Starting Testing That Uses the Test Pattern To use the test pattern during testing with Command S-Register 16 AT&M0S16=12. The &T test 1.
14-12 CHAPTER 14: TESTING THE CONNECTION
15 TROUBLESHOOTING This chapter explains how to troubleshoot the Business Modem. This chapter is divided into these sections: ■ Problems that occur before connecting. ■ Problems that occur after connecting. ■ What to do if you still have problems. Problems That Occur Before Connecting No response to AT For Windows users, make sure that you set the correct COM port and IRQ in your communications software and, if applicable, in Windows' Control Panel - Ports.
15-2 CHAPTER 15: TROUBLESHOOTING ■ Make sure that verbal result codes (status messages) are enabled. Send these commands to the Business Modem: For your modem to Command enable message display ATQ0 Display verbal messages ATV1 ■ Review your communications software manual to see what Carrier Detect (CD) operations your software requires. Then see the chapter about Controlling EIA-232 Signaling.
Problems That Occur Before Connecting 15-3 Double characters are appearing on your monitor This is a signal that both the Business Modem's local echo and your software's local echo are on. Type the command to turn off your online echo (ATF1) or turn your communications software's local echo off (refer to your software's documentation). After you dial, the Business Modem reports NO CARRIER and then hangs up ■ Try increasing S7 and decreasing S9 to allow more time for the connection.
15-4 CHAPTER 15: TROUBLESHOOTING Problems that Occur After Connecting Your screen displays random or "garbage" characters Make sure that the Business Modem is set to the same bit rate, word length, parity, and number of Stop bits as the device to which you are connecting. If the settings are correct, the problem may be with the phone line. Try the following measures: ■ Place the call again. The phone company routes even local calls differently each time you call.
Problems that Occur After Connecting 15-5 Mainframe computer keeps dropping your connection You must turn off the Business Modem's result codes and character echo (ATQ1E0). The modem at the mainframe also needs to be set to ATQ1E0. Bad faxes or can't fax ■ Make sure the fax software is set to use Class 1 fax. Refer to your fax software's manual. ■ If you use memory-resident programs (TSRs-Terminate and Stay Resident programs) or disk-caching programs, they may be interfering.
15-6 CHAPTER 15: TROUBLESHOOTING ■ If you are attempting to make a connection using HST modulation, make sure that the modem at the other end of the line is HST compatible, V.32 terbo compatible at 14.4 Kbps, V.32 compatible at 9600 bps, V.22 bis-compatible at 2400 bps, Bell 212A-compatible at 1200 bps, or Bell 103-compatible at 300 bps. ■ If none of the above corrects the problem, it's likely that the quality of the phone connection is poor.
Problems that Occur After Connecting 15-7 5 If you do return the Business Modem to us, please follow these procedures: a Ship the unit, postage pre-paid, in its original container. If the original container is not available, pack the unit carefully in a strong box of corrugated cardboard with plenty of packing material. b Be sure to include your SRO number inside the package, along with your name and address. Put your return address and your SRO number on the shipping label as well.
15-8 CHAPTER 15: TROUBLESHOOTING
16 UPGRADING YOUR MODEM This chapter contains information about: ■ Checking your modem’s software version ■ Getting new operating software ■ Sending new software to the modem ■ If your modem doesn’t respond Overview 3Com periodically releases updates and enhancements to the modem’s operating software which are made publicly available from our Web site, BBS, and ftp site. Checking Your Business Modem’s Software Version Issuing the ATI7 command produces the following information.
16-2 CHAPTER 16: UPGRADING YOUR MODEM Check the Supervisor and Digital Signal Processor (DSP) dates found in the last two lines of the screen display. These dates will determine which version of the software your modem is using. The best way to find out the current shipping version of the modem’s software is to visit the 3Com U.S. Robotics Web site at http://www.usr.com/home/online. Getting New Operating Software To get the newest version of the Business Modem’s operating software: ■ Go to the 3Com U.
Sending New Software to your modem 16-3 2 Enter AT~X!. The modem should respond as follows: at~x! SDL Xmodem file transfer - (Y)es (N)o (T)est > 3 Type t to start an integrity test of the XMD file. Your screen should appear as follows: 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 file to your modem using the XMODEM-Checksum or XMODEM-CRC protocol.
16-4 CHAPTER 16: UPGRADING YOUR MODEM If Your Modem Doesn’t Respond If your modem doesn’t respond after the flash process, its memory may be corrupted. Follow these steps to force the new software to the modem. 1 Power your modem off. The power switch is in the rear right corner of the back panel. 2 While holding in the RESET button (between the RS-232 and USB jacks), turn the modem back on. 3 Start your communications software package. Set your port speed to 57,600 bps, type AT and press .
A Understanding Bit-Mapped S-Registers S-REGISTERS A bit-mapped S-Register uses one number to describe a collection of settings. Bit-mapping allows us to pack a lot of information in a small space. Bit-mapped registers are in the form of Sr.b=n, where r is the bit-mapped register;.b is the bit; n is 0 (off) or 1 (on). The modem displays the value of an S-Register, as a decimal value between 0 and 255. The modem, however, understands the decimal value as a collection of binary digits (bits).
A-2 APPENDIX A: S-REGISTERS Converting Bits to Decimal Values Starting with a string of eight bits, assign each "1" bit a value based on its position. Add the values to come up with the final decimal value. Here’s an example of how bits are converted to decimal values: 01001111 Converting Decimal Values to Bits 0 1 0 0 1 1 1 0 + 64 +0 +0 +8 +4 +2 1 + 1 = 79 Convert decimal values to bits by finding the largest decimal equivalent that is less than the decimal value.
Using Bits Using Bits A-3 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). Example: ATS13.0=1.4=1.5=1, turns bits 0, 4, and 5 on for S-Register 13. Using Decimal Values An alternative way to set bit-mapped S-Registers is by adding the decimal values of the bits and entering the total.
A-4 APPENDIX A: S-REGISTERS S-Registers Function NVRAM Default Setting S21 Break length, 10 ms 10 S22 XON character 17 S23 XOFF character 19 S24 Pulsed DSR duration, 20 ms 150 S25 DTR recognition time, 10 ms 5 S26 RTS/CTS delay time, 10 ms 1 S27 Bit-mapped functions* 0 S28 V.32 handshake time, 100 ms 8 S29 V.
A complete list of S-Registers A complete list of S-Registers A-5 . 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 Business Modem answers on the first 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 “+”. A value of 128-255 disables the escape code.
A-6 APPENDIX A: S-REGISTERS Register Default Function S13 0 Bit-mapped register. See the beginning of this appendix for information about setting bit-mapped registers. S14 S15 1 0 Bit Value Result 0 1 Reset when DTR drops. 1 2 Reverse normal Auto Answer operation: On incoming RING, enter Originate Mode and look for an answer tone. 2 4 Disable 250 ms pause before result code display. 3 8 On DTR signal, autodial the number stored in NVRAM at position 0.
A complete list of S-Registers Register Default A-7 Function 4 16 Disable MNP Level 4; retransmitting the larger Level 4 data blocks may be a problem if you expect a great number of errors during a call. 5 32 Set Backspace key to delete. 6 64 Some earlier 2400 bps MNP modems, not made by 3Com or Microcom, were not fully compatible with the MNP protocol. If you have difficulty making a successful 2400 bps MNP connection with a remote MNP modem, it may be because of this incompatibility.
A-8 APPENDIX A: S-REGISTERS Register Default Function S19 0 Sets the duration, in minutes, for the Inactivity Timer. The timer activates when there is no data activity on the R232 interface, and at the timeout the Business Modem hangs up. S19=0 disables the timer. S21 10 Sets, in 10-millisecond units, the length of breaks sent from the Business Modem to the computer or terminal. Applies to ARQ mode only. S22 17 Stores the ASCII code for the XON character.
A complete list of S-Registers Register Default A-9 Function Error control handshaking options: Select the total value of bits 4 and 5 S28 8 Bit 4 Bit 5 Result 0 0 Complete handshaking sequence: V.42 Detection, LAPM error control, MNP. 16 0 Disable MNP. 0 32 Disable V.42 Detection and LAPM. 16 32 Disable Detection phase, if you know that the remote Business Modem does LAPM, but not the Detection phase.
A-10 APPENDIX A: S-REGISTERS Register S38 Default 0 Function 4 16 Change MR to DSR 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. Default = 0: The Business Modem immediately hangs up when DTR drops.
A complete list of S-Registers Register Default A-11 Function 0 1 Dial security enabled. 1 2 Prompting enabled. 2 4 Local-access password protection enabled. Enabling local-access password protection disables the &Zn=s command (which stores up to 10 phone numbers) because stored phone numbers occupy the same space in NVRAM as the dialback numbers for Dial Security accounts. S54 S55 S56 64 0 0 Symbol rate bit-mapped register used primarily by 3Com Technical Support for debugging purposes.
A-12 APPENDIX A: S-REGISTERS Register S58 S69 S70 Default 0 0 0 Function 2 4 Disable preemphasis. 3 8 Disable precoding. 4 16 Disable shaping. 5 32 Disable V.34+ 6 64 Disable V.34. 7 128 Disable V.FC. Bit-mapped register. See the beginning of this appendix for information about setting bit-mapped registers. Bit Value Result 0 1 Disable x2 5 32 Enables/Disables V.90 Bit-mapped register.
B ALPHABETIC COMMAND SUMMARY This appendix contains an alphabetic listing of the AT commands to which the modem will respond. Default settings are bold. Basic Command Set Command Function $ Display help for the Basic command set. +++ Escape code. Once your 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.
B-2 APPENDIX B: ALPHABETIC COMMAND SUMMARY Command Function Bn Set handshaking options. B1 Cn Bell answer tone. This setting selects HST modulation, but use it only if the modem is not required to answer V.34-type calls. Enable or disable the transmitter. C0 Transmitter disabled; for receiving only. C1 Transmitter enabled. With the exception of the Dial options, modems ignore any commands issued after D in the same command string.
Basic Command Set B-3 ! Flash the switchhook (off hook 0.5 seconds, on hook 0.5 seconds, then off hook). Use ! when other modems share the line. 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. En Command mode echo. Enables or disables the display of your typed commands. E0 Command mode echo OFF.
B-4 APPENDIX B: ALPHABETIC COMMAND SUMMARY Command Function Kn Control the modem clock. ATI6 displays the time. Mn On Qn K0 If online, display current call duration. If offline, display last call’s duration. K1 Display the actual time. Set the clock using ATI3=HH:MM:SS K1. Control when the speaker sounds M0 The speaker is always off. M1 The speaker is on until the call is negotiated. M2 The speaker is always on.
Ampersand (&) Command Set Command Function Z Ampersand (&) Command Set B-5 X3 Ignore Dial Tone X4 Microsoft default X7 Business Modem default Software reset. Pressing the RESET button on the rear panel of the modem resets the modem to the &F0 configuration template (no flow control). Command Function &$ Display help for the ampersand (&) command set. &An Enable or disable the display of additional result code subsets. (Also, see the Xn command.) &Bn &A0 Do not display ARQ result codes.
B-6 APPENDIX B: ALPHABETIC COMMAND SUMMARY Command Function &C1 &Dn Normal operations. The modem sends a CD signal when it connects with another modem and drops the CD when it disconnects. Control how the modem responds to Data Terminal Ready (DTR) signals. &D0 DTR is always ON (ignored). &D1 If issued before connecting with another device, the Business Modem can enter online Command mode during a call by dropping DTR. &D1 functions similarly to the escape code (+++).
Ampersand (&) Command Set Command &In &Kn B-7 Function &H1 Use hardware flow control. Requires that your computer and software support Clear to Send (CTS) at the EIA-232 interface. &H2 Use software flow control. Requires that your software support XON/XOFF signaling. &H3 Use both hardware and software flow control. If you are unsure about what your equipment supports, select this option. Received data software flow (XON/OFF) control. &I0 Disables XON/XOFF flow control of received data.
B-8 APPENDIX B: ALPHABETIC COMMAND SUMMARY Command Function &K3 &Ln Line type. &L0 &Mn Selective data compression. The modem negotiates only for V.42bis compression, and disables MNP Level 5 (MNP5) compression. Use this setting to transfer compressed files. Normal. Enable ARQ (error control) protocol. Both your 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 calls above 2400 bps.
Ampersand (&) Command Set Command &Rn B-9 Function n=13 26400 bps n=14 28800 bps n=15 31200 bps n=16 33600 bps n=17 28000 bps n=18 29333 bps n=19 30666 bps n=20 32000 bps n=21 33333 bps n=22 34666 bps n=23 36000 bps n=24 37333 bps n=25 38666 bps n=26 40000 bps n=27 41333 bps n=28 42666 bps n=29 44000 bps n=30 45333 bps n=31 46666 bps n=32 48000 bps n=33 49333 bps n=34 50666 bps n=35 52000 bps n=36 53333 bps n=37 54666 bps n=38 56000 bps n=39 57333 bps
B-10 APPENDIX B: ALPHABETIC COMMAND SUMMARY Command Function &R2 &Sn &Tn Enable hardware flow control of received data. The modem sends data to the computer only upon receipt of the RTS signal. Send the computer a Data Set Ready (DSR) signal via the EIA-232 interface. ("Data Set" is industry jargon for modem.) &S0 DSR is always ON (override). &S1 In Originate mode: Send DSR after dialing, on detection of the remote device’s answer tone. In Answer mode: Send DSR after sending an answer tone.
Percent (%) Command Set Command B-11 Function &Y0 Destructive, don't send break. &Y1 Destructive, expedited. &Y2 Nondestructive, expedited. &Y3 Nondestructive, unexpedited; the 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-thannormal throughput.
B-12 APPENDIX B: ALPHABETIC COMMAND SUMMARY Command Function %An Create and configure security accounts. %Bn Remotely configure a modem's serial port rate. %Cn %B0 110 bps %B1 300 bps %B2 600 bps %B3 1200 bps %B4 2400 bps %B5 4800 bps %B6 9600 bps %B7 19200 bps %B8 38400 bps %B9 57600 bps %B10 115200 bps Remote configuration control. %C0 Defer configuration changes until the call is ended. Changes take effect for ensuing connections.
Octothorpe (#) Command Set Command Function %Fn Remotely configure another device’s 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. B-13 %L= Set a local-access password. %Pn= Disable password security (n=0 or n=1) when no character follows the equal sign. %Pn=s Set the following password (s) for viewing privileges only (n = 0), or view and configuration privileges (n= 1). %Pn? Display password n.
B-14 APPENDIX B: ALPHABETIC COMMAND SUMMARY
C Hardware Flow Control FLOW CONTROL TEMPLATE The table below lists the Hardware flow control template. To load this template send AT&F1 to your modem.
C-2 APPENDIX C: FLOW CONTROL TEMPLATE NVRAM Options Setting Description Error control &M4 Normal/error control Link rate select &N0 Variable Pulse dialing type &P0 U.S./Canada Record data hardware flow control &R2 Enabled Data Set Ready &S0 Always on Remote Digital Loopback (RDL) &T5 Deny RDL Break handling &Y1 Clear buffer, send immediately Stored telephone number &Z0-9=0 Blank Caller ID #CID=0 Caller ID disabled Word length* 8 Parity* 0 None DTE rate* (Kbps) 19.
Software Flow control Software Flow control C-3 The table below lists the Software flow control template. To load this template send AT&F2 to the modem. .
C-4 APPENDIX C: FLOW CONTROL TEMPLATE NVRAM Options Setting Description Stored telephone number &Z0-9=0 Blank Caller ID #CID=0 Caller ID disabled Word length* 8 Parity* 0 None DTE rate* (Kbps) 19.2 _ * Detected by each modem from the AT prefix of the &W command 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... &W string.
No Flow Control NVRAM Options Setting Description Record data software flow control &I0 Disabled Analog data compression &K1 Enabled Normal lines &L0 Normal lines Error control &M4 Normal/error control Link rate select &N0 Variable Record data hardware flow control &R1 Disabled Data Set Ready &S0 Always on Remote Digital Loopback (RDL) &T5 Deny RDL Break handling &Y1 Clear buffer, send immediately Stored telephone number &Z0-9=0 Blank Word length* 7 Parity* 1 Even DTE
C-6 APPENDIX C: FLOW CONTROL TEMPLATE
D Result Code Meanings RESULT CODE MEANINGS AND SETS 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.
D-2 APPENDIX D: RESULT CODE MEANINGS AND SETS Result Codes Sets for Xn Values Result Codes X0 X1 X2 X3 X4 X5 X6 X7 0/OK ❷ ❷ ❷ ❷ ❷ ❷ ❷ ❷ 1/CONNECT ❷ ❷ ❷ ❷ ❷ ❷ ❷ ❷ 2/RING ❷ ❷ ❷ ❷ ❷ ❷ ❷ ❷ 3/NO CARRIER ❷ ❷ ❷ ❷ ❷ ❷ ❷ ❷ 4/ERROR ❷ ❷ ❷ ❷ ❷ ❷ ❷ ❷ ❷ ❷ ❷ ❷ ❷ ❷ ❷ 5/CONNECT 1200 6/NO DIAL TONE ❷ ❷ 7/BUSY ❷ ❷ ❷ ❷ ❷ 8/NO ANSWER ❷ ❷ ❷ ❷ ❷ ❷ ❷ ❷ ❷ ❷ 11/RINGING ❷ ❷ ❷ 12/VOICE ❷ ❷ 10/CONNECT 2400 ❷ ❷ ❷ ❷ 13/CONNECT 9600 ❷ ❷ ❷ ❷
TECHNICAL INFORMATION E Technical Specifications Your modem uses multiple standard data communications protocols and is also compatible with many nonstandard schemes. The following schemes are supported: Modulation This modulation Supports V.90 ITU 56K standard, server capabilities. V.90 analog clients can call into your Business Modem to get 56K connections x2 Up to 56 Kbps downstream and V.34 speeds upstream ITU-T V.34 33.6/31.2/28.8/26.4/24/21.6/19.2/16.8/14.
E-2 APPENDIX E: TECHNICAL INFORMATION Error Control, Data Compression, Testing, and Dialing Fax This modulation Supports ITU-T V.23 1200 bps asymmetrical with 75 bps back channel with Frequency Shift Keying (FSK), used by some U.K. and European phone systems. Bell 103 300 bps (ITU-T V.21 optional) asynchronous, Frequency Shift Keying (FSK) This Supports ITU-T V.
Technical Specifications Additional Specifications Serial Ports E-3 This feature Supports Supported serial port rates 230400, 115200, 57600, 38400, 19200, 9600, 4800, 2400, 1200, and 300 bps Adaptive Speed Leveling (ASL) 21600, 19200, 16800, 14400, 12000, 9600, 7200, and 4800 bps Serial port connector DB-25 Communications channel Full- or half- duplex on 2-wire phone lines; demand-driven high-speed turnaround in HST mode; symmetrical speeds in V.32 bis.
E-4 APPENDIX E: TECHNICAL INFORMATION The EIA-232 Interface Your modem’s serial port is factory set to signal according to the EIA-232 standard. See Figure A-1, Signals at your Business Modem's Serial Port. Wiring a DB-25 to DB-9 Cable DB-9 connectors for PCs should be wired at the computer end of the cable as shown below. Minimum Requirements Some computer/terminal equipment supports only a few of your modem’s EIA-232 signals.
Technical Specifications Flow Control Requirements E-5 If your computer and software support Clear to Send and you wish to use Transmit Data hardware flow control (&H1), Pin 5 (DB-25) or Pin 8 (DB-9) is required. If your computer and software support Request to Send and you wish to use Received Data hardware flow control (&R2), Pin 4 (DB-25) or Pin 7 (DB-9) is required.
E-6 APPENDIX E: TECHNICAL INFORMATION Serial Ports (Macintosh modem) These are the signals generated or accepted by your modem’s serial port:
F ASCII CHART Dec Hex Char Dec Hex Char Dec Hex Char Dec Hex Char 00 00 NUL 32 20 SP 64 40 @ 96 60 ` 01 01 SOH 33 21 ! 65 41 A 97 61 a 02 02 STX 34 22 "66 42 B 98 62 b 03 03 ETX 35 23 # 67 43 C 99 63 c 04 04 EOT 36 24 $ 68 44 D 100 64 d 05 05 ENQ 37 25 % 69 45 E 101 65 e 06 06 ACK 38 26 & 70 46 F 102 66 f 07 07 BEL 39 27 ë 71 47 G 103 67 g 08 08 BS 40 28 ( 72 48 H 104 68 h 09 09 HT 41
F-2 APPENDIX F: ASCII CHART Dec Hex Char Dec Hex Char Dec Hex Char Dec Hex Char 24 18 CAN 56 38 8 88 58 X 120 78 x 25 19 EM 57 39 9 89 59 Y 121 79 y 26 1A SUB 58 3A : 90 5A Z 122 7A z 27 1B ESC 59 3B ; 91 5B [ 123 7B { 28 1C FS 60 3C < 92 5C \ 124 7C | 29 1D GS 61 3D = 93 5D ] 125 7D } 30 1E RS 62 3E > 94 5E à 126 7E ~ 31 1F US 63 3F ? 95 5F _ 127 7F DEL
G Fax Service Class 1 Commands FAX Service Class 2.0 Commands FAX INFORMATION FOR PROGRAMMERS +FCLASS? What mode is in use Data or Fax? +FCLASS=n (0,1,2.0) Class identification 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.
G-2 APPENDIX G: FAX INFORMATION FOR PROGRAMMERS Fax Mode Flow Control Setting Many facsimile software products use software flow control when the modem is in Fax mode. Throughout our documentation, we recommend that you use hardware flow control for Data mode (factory setting). However, to allow compatibility with software products that use software flow control by default, 3Com fax modems automatically change to software flow control when entering Fax mode.
H VIEWING LEDS This appendix explains how to view the twelve LEDs on the front of your Business Modem.
H-2 APPENDIX H: VIEWING LEDS This LED Status Means your Business Modem TR On RS232 mode: has detected DTR signal USB mode: has detected successful USB registration Off RS232 mode: has not detected DTR USB mode: has not detected successful USB registration CD RS CS On Has detected a carrier from a remote device or carrier detect has been forced on Off Has not detected a carrier On Has detected the Ready to Send (RTS) signal from your computer Off Has not detected the RTS signal from your
I S-Registers S-REGISTERS 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 Business Modem answers on the first 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 "+". A value of 128-255 disables the escape code.
I-2 APPENDIX I: S-REGISTERS Register Default Function S10 7 Sets the duration, in tenths of a second, that the Business Modem waits after loss of carrier before hanging up. This guard time allows the Business Modem to distinguish between a line hit, or other disturbance that momentarily breaks the connection, from a true disconnect (hanging up) by the remote device S11 70 Sets the duration and spacing, in milliseconds, of dialed tones.
S-Registers Register Default Function S15 0 Bit-mapped register. (See Chapter 1, Using the AT Command Set, for instructions about how to set bit-mapped registers.) I-3 Bit Value Result 0 1 Disable the Business Modem's extra high-frequency equalization if it causes problems on shorter-link calls (for HST modulation only). 1 2 Disable online fallback. 2 4 Disable 450 bps back channel* HST only. 3 8 Reset non-ARQ mode Transmit buffer from 1.5K bytes to 128.
I-4 APPENDIX I: S-REGISTERS Register Default Function S16 0 Bit-mapped register. (See Chapter 1, Using the AT Command Set, for instructions on setting bit-mapped registers.) For testing, see Chapter 14, Testing. Bit Value Result 2 4 Test pattern. 3 8 Remote digital loopback. S18 0 Test timer for software-initiated loopback testing (&Tn); disabled when S18 is set to 0. Used to set the duration of testing, in seconds, before the Business Modem automatically times out and terminates the test.
S-Registers Register Default I-5 Function Bit Value Result 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. The call's actual rate can be viewed on the ATI6 screen. Error control handshaking options: Select the total value of bits 4 and 5.
I-6 APPENDIX I: S-REGISTERS Register Default Function Bit Value Result 1 2 Disable the Business Modem's enhanced, proprietary V.32bis modulation. Used for troubleshooting. 2 4 Disable the faster retrains that occur during proprietary V.32terbo modulation. Used for troubleshooting. 3 8 Enable V.23. Required for some British connections. 6 64 Disable the remote-access busy message. 7 128 Disable V.32terbo.
S-Registers Register Default Function Bit S53 126 I-7 Value Result Bit-mapped register. (See Chapter 1, Using the AT Command Set, for instructions about how to set bit-mapped registers.) 0 1 Enable dial security. 1 2 Enable autopass fallback. 2 4 Enale local-access password protection.
I-8 APPENDIX I: S-REGISTERS Register Default Function S56 0 Bit-mapped register primarily used by 3Com Technical Support for debugging purposes. S58 S70 0 0 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. 5 32 Disable V.34+. 6 64 Disable V.34. 7 128 Disable V.FC. Bit-mapped register primarily used by 3Com Technical Support for debugging purposes.
J WARRANTY 3COM CORPORATION LIMITED WARRANTY 3Com OfficeConnect 56K Business Modem 3Com warrants this hardware product to be free from defects in workmanship and materials, under normal use and service, for the lifetime of the product from the date of purchase from 3Com or its authorized reseller.
J-2 APPENDIX J: WARRANTY data on and after January 1, 2000, and Customer notifies 3Com before the later of April 1, 2000, or ninety (90) days after purchase of the product from 3Com or its authorized reseller, 3Com shall, at its option and expense, provide a software update which would effect the proper performance of such product, repair such product, deliver to Customer an equivalent product to replace such product, or if none of the foregoing is feasible, refund to Customer the purchase price paid for
3COM CORPORATION LIMITED WARRANTY J-3 OF LAW, STATUTORY OR OTHERWISE, INCLUDING WARRANTIES, TERMS, OR CONDITIONS OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, SATISFACTORY QUALITY, CORRESPONDENCE WITH DESCRIPTION, AND NON-INFRINGEMENT, ALL OF WHICH ARE EXPRESSLY DISCLAIMED. 3COM NEITHER ASSUMES NOR AUTHORIZES ANY OTHER PERSON TO ASSUME FOR IT ANY OTHER LIABILITY IN CONNECTION WITH THE SALE, INSTALLATION, MAINTENANCE OR USE OF ITS PRODUCTS.
J-4 APPENDIX J: WARRANTY GOVERNING LAW: This Limited Warranty shall be governed by the laws of the State of California, U.S.A. excluding its conflicts of laws principles and excluding the United Nations Convention on Contracts for the International Sale of Goods. Important: If you send your unit, pack it securely and be sure your SRO number is visible on the outside of the package. Notices FCC Certification Statement 3Com 3800 Golf Rd.
FCC Notice: Radio and Television Interference J-5 FCC Notice: Radio and Television Interference This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation.
J-6 APPENDIX J: WARRANTY IC (Industry Canada) This digital apparatus does not exceed the Class B limits for radio noise emissions from digital apparatus set out in the interference-causing equipment standard entitled Digital Apparatus, ICES-003 of Industry Canada.
GLOSSARY 16550 UART Adaptive Speed Leveling (ASL) analog signals The fastest type of UART that is currently available. Business Modem V.32 bis and V.32 terbo 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 constantly ensuring data integrity.
2 GLOSSARY dynamically reverse the channels during a call if the volume of data transfer changes. asynchronous transmission Data transmission in which the length of time between transmitted characters may vary. Because the time lapses between transmitted characters are not uniform, the receiving modem must be signaled as to when the data bits of a character begin and when they end. The addition of start and stop bits to each character serves this purpose.
GLOSSARY 3 copies of transmitted frames until they are positively acknowledged by the receiving modem. byte call indicate A group of binary digits stored and operated upon as a unit. A byte may have a coded value equal to a character in the ASCII code (letters, numbers), or have some other value meaningful to the computer. In user documentation, the term usually refers to 8-bit units or characters. 1 kilobyte (K) is equal to 1,024 bytes or characters; 64K indicates 65,536 bytes or characters.
4 GLOSSARY Class 1/EIA-578 An American standard used between facsimile application programs and facsimile modems for sending and receiving Class 1 faxes. Class 2.0/EIA-592 An American standard used between facsimile application programs and facsimile modems for sending and receiving Class 2.0 faxes. CO COM port cps See central office. See serial port, EIA-232. See characters per second. CPU Central processing unit. CRC See cyclic redundancy check.
GLOSSARY data mode data set data terminal equipment (DTE) DCE 5 The mode in which the fax modem is capable of sending and receiving data files. A standard modem without fax capabilities is always in Data mode. Another way of saying "modem." The device that generates or is the final destination of data. See data communication equipment. default Any setting assumed, at startup or reset, by the computer's soft-ware and attached devices, and operational until changed by the user.
6 GLOSSARY error control Various techniques which check the reliability of characters (parity) or blocks of data. V.42, MNP and HST error control protocols use error detection (CRC) and retransmission of errored frames (ARQ). expansion bus A series of slots inside a computer that allow for adding feature cards. facsimile (fax) A method for transmitting the image on a printed page from one point to another.
GLOSSARY HDLC High Speed Technology (HST) Hz (Hertz) See High Level Data Link Control. 3Com' proprietary signaling scheme, design and error control protocol for high-speed modems. HST incorporates trellis-coded modulation, for greater immunity from variable phone line conditions, and asymmetrical modulation for more efficient use of the phone channel at speeds of 4800 bps and above. HST also incorporates MNP-compatible error control procedures adapted to asymmetrical modulation.
8 GLOSSARY local echo MB Microcom Networking Protocol (MNP) MI/MIC MNP modem Nonvolatile Random Access Memory (NVRAM) NVRAM online fallback A modem feature that enables the modem to send copies of key-board commands and transmitted data to the screen. When the modem is in Command mode (not online to another system) the local echo is invoked through the ATE1 command. The command causes the modem to display your typed commands.
GLOSSARY originate mode parallel transmission parity 9 A state in which the modem transmits at the predefined low frequency of the communications channel and receives at the high frequency. The transmit/receive frequencies are the reverse of the called modem which is in Answer mode. The transfer of data characters using parallel electrical paths for each bit of the character, for example, 8 paths for 8-bit characters.
10 GLOSSARY Read-Only Memory (ROM) Permanent memory, not user-programmable. The Business Modem's factory settings are stored in ROM. remote access A feature that allows a remotely-located user to view the Business Modem's configuration screens and change the Business Modem's configuration. Password protection is available. remote digital loopback A test that checks the phone link and a remote modem's transmitter and receiver.
GLOSSARY stop bit shunt S-register switch 11 The signaling bit attached to the end of each character before characters are transmitted during Asynchronous Transmission. 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. An area of NVRAM that is used to store a setting. See central office switch.
12 GLOSSARY V.17 V.21-Fax An ITU-T standard for facsimile operations that specifies modulation at 14.4 Kbps, with fallback to 12 Kbps. An ITU-T standard for facsimile operations at 300 bps. 3Com or compatible fax devices then transmit or receive at higher speeds. V.21-Modem An ITU-T standard for modem communications at 300 bps. Modems made in the U.S. or Canada follow the Bell 103 standard. However, the modem can be set to answer V.21 calls from overseas. V.
GLOSSARY 13 speed when line quality is impaired, and fall back further as necessary. They fall forward to the next higher speed when line quality improves. V.32 terbo Modulation scheme that extends the V.32 connection range: 4800, 7200, 9600, 12K, 14.4K, 16.8K, 19.2K, and 21.6 Kbps. V.32 terbo modems fall back to the next lower speed when line quality is impaired, and fall back further as necessary. They fall forward to the next higher speed when line quality improves. V.
14 GLOSSARY
