MultiModem MT2834MR6 User Guide
MultiModem MT2834MR6 User Guide PN: S000326A Copyright ©2003 by Multi-Tech Systems, Inc. All rights reserved. This publication may not be reproduced, in whole or in part, without prior written permission from MultiTech Systems, Inc. Multi-Tech Systems, Inc. makes no representations or warranties with respect to the contents hereof and specifically disclaims any implied warranties of merchantability or fitness for any particular purpose. Furthermore, Multi-Tech Systems, Inc.
Contents Chapter 1.1 1.2 1.3 1.4 1 - Introduction ..................................................................................... 7 Introduction ............................................................................................. 8 Manual Organization ............................................................................... 8 Description ............................................................................................. 9 FCC Regulations for Telephone Line Interconnection ...
3.13 3.14 3.15 3.16 Escape Sequences .............................................................................. 52 Remote Configuration Commands ....................................................... 53 Line Probe Commands ........................................................................ 54 Diagnostic Commands......................................................................... 55 Chapter 4.1 4.2 4.3 4 - S-Registers .........................................................................
.10.6 Pacing (Computer-Initiated Flow Control) ............................................ 74 5.10.7 Data Compression .............................................................................. 74 5.11 Result Codes........................................................................................ 75 5.11.1 MNP Error Correction .......................................................................... 75 5.11.2 LAP-M Error Correction ................................................................
Appendix B .................................................................................................... 92 Dial Pulses ...................................................................................................... 92 Tone Dial Frequencies ..................................................................................... 93 Appendix C .................................................................................................... 94 Result Code Summary ................................
Chapter 1 - Introduction
Chapter 1 - Introduction 1.1 Introduction Welcome to the world of data communications. You have acquired one of the finest rack-mount intelligent modems available, the MT2834MR6, from Multi-Tech Systems. This owner’s manual will help you install, configure, test, and use your modem. Your MT2834MR6 is designed to operate as an enhanced ITU-T V.34 dial-up modem. As such, it includes the advanced features of Multi-Tech standalone modems, such as the popular MultiModemZDXb.
Chapter 1 - Introduction 1.3 Description Each MT2834MR6 card contains six integrated 33,600 bps MultiModems. Each modem on the MT2834MR6 card can be configured independently of the others via the MultiModemManager controller card (Model MR4800 or MR4800E), which can support and control up to 16 MultiModem cards per rack. Refer to your MultiModemManager Owner’s Manual for more information about the rack and its components. Perhaps the most significant extras incorporated in the MT2834MR6 are its V.
Chapter 1 - Introduction 1.4 FCC Regulations for Telephone Line Interconnection 1. No repairs are to be made by you. Repairs are to be made only by Multi-Tech Systems or its licensees. Unauthorized repairs void registration and warranty. Contact Multi-Tech Systems, Inc. for details of how to have repairs made. 2.
Chapter 1 - Introduction 1.5 Canadian Limitations Notice Notice: The ringer equivalence number (REN) assigned to each terminal device provides an indication of the maximum number of terminals allowed to be connected to a telephone interface. The termination of a interface may consist of any combination of devices subject only to the requirement that the sum of the ringer equivalence numbers of all the devices does not exceed 5. Notice: The Industry Canada label identifies certificated equipment.
Chapter 1 - Introduction 1.6 Technical Specifications Model Number Data Rates (Modem) Data Rates (Fax) Data Format (Modem) Configuration Compatibility (Modem) Compatibility (Fax) Error Correction Data Compression Speed Conversion Flow Control Mode of Operation Intelligent Features AT Commands Command Buffer Automatic Dialing Modem Modulations Fax Modulations Carrier Frequencies ITU-T V.34 Carrier Frequencies: AT&T V.32 terbo/ ITU-T V.32bis/V.32 Carrier Frequencies: V.22bis/V.
Chapter 1 - Introduction Carrier Frequencies: Bell 103/113 (300 bps) Transmit originate: Receive originate: Transmit answer: Receive answer: Carrier Frequencies: V.21 Transmit originate: Receive originate: Transmit answer: Receive answer: Carrier Frequencies: V.
Chapter 1 - Introduction Firmware Upgrades Indicators Controls Environmental Power Requirements Power Consumption Dimensions, card modem Weight Limited Warranty Fuses 1.7 Via flash PROM technology on Multi-Tech’s BBS LEDs for Transmit Data, Receive Data, Carrier Detect, Speed, and Off Hook/OutOf-Service Toggle switches for busy-out Temperature range: 0°–50° C (32°–120° F) Humidity range: 20–90% (noncondensing) 5 VDC at 0.95 A ±16 VDC at 0.1 A Approximately 6 watts .9 × 11 × 15 in. (2.
Chapter 1 - Introduction 1.8 Modem LED Indicators The MT2834MR6 has five LED indicators per modem: TD Transmit Data. This LED blinks when data is being transmitted, on for a space, off for a mark. The state of this LED matches that of the TD circuit on Pin 2 of the RS-232C interface. RD Receive Data. This LED blinks when data is received, on for a space, off for a mark. The state of this LED matches that of the RD circuit on Pin 3 of the RS-232C interface. CD Carrier On.
Chapter 1 - Introduction 1.10 MT2834MR6 Installation Notes All installation must be done by a qualified service person. The installation instructions in your MultiModemManager Owner’s Manual include information about the use of blanking plates to cover empty slots in the card frame. Be sure to follow those instructions.
Chapter 2 - Dialing and Answering
Chapter 2 - Dialing and Answering 2.1 Introduction This chapter describes the dialing and answering capabilities of the MT2834MR6 modems, which are standard ITU-T V.34 full duplex dial-up modems. 2.2 Dial-Up Automatic Answering The MT2834MR6 can answer calls automatically. The MT2834MR6 is in originate mode in its idle state. When it detects an incoming call, it automatically switches to answer mode.
Chapter 2 - Dialing and Answering 2.4 Call Termination There are several methods by which you can terminate a call, or simply stated, hang up: 1. Command Mode Control. It is possible to enter command mode while remaining online by entering an escape sequence (+++AT in most cases). From command mode, you can return to the online state by typing ATO, or you can terminate the call by using the H command. Typing ATH will hang up the line (bring it on-hook).
Chapter 3 - AT Commands
Chapter 3 - AT Commands 3.1 Working with AT Commands The MT2834MR6’s modems are controlled by instructions called AT commands, so called because the attention characters AT precede each command or command string (sequence of commands). You can send commands to the modem from your keyboard while in terminal mode, or you can use communications software to issue these commands automatically. The MT2834MR6 is in command mode when it is not dialing or online.
Chapter 3 - AT Commands 3.2.2 Command Structure You can control a wide variety of modem operations and options when the modem is in command mode. AT commands tell the modem to dial a number, to answer a call, to operate at a certain speed, to use a certain compression technique, and many other functions. AT commands consist of one or two letters, which may be preceded by an ampersand (&), a dollar character ($), a pound character (#), a percent character (%), or a greater-than character (>).
Chapter 3 - AT Commands Table 3-1. AT Commands by Function Topic: Command: Description: Dialing Action D A: H Dial Continuous redial On-hook/off-hook Dial Modifiers P T W R , : ; ! @ $ Pulse dialing Tone dialing Wait for new dial tone Reverse originate/answer mode Dialing pause Continuous redial Return to command mode after dialing Flash on-hook Quiet answer Call card tone detect Phone Number Memory D...N N N...
Chapter 3 - AT Commands Table 3-1. AT Commands by Function (con't) Topic: Command: Description: V.34 Controls %F &RA #V Echo canceler frequency offset comp. Asymmetric bit rate V.
Chapter 3 - AT Commands Table 3-1.
Chapter 3 - AT Commands 3.2 Dialing Commands Dialing commands are used to dial and to hang up. Ds Dial s = phone number Default: none The letter D in a command causes the modem to dial the telephone number immediately following it. For example, if you type ATD5551212, the modem dials the number 5551212. The MT2834MR6 supports several dialing methods. With the D command, you can specify either pulse (ATDP) or tone (ATDT) dialing.
Chapter 3 - AT Commands 3.3 Dial Modifier Commands The dial string can include the digits 0 through 9, the pound sign (#), the asterisk (*), and the letters A, B, C, or D. The latter are used by some PBXs; the exact function will depend on the PBX manufacturer’s feature set and implementation. There are also several command characters, called “dial modifiers,” that can be included within a dialing command after the letter D.
Chapter 3 - AT Commands , Dialing Pause Enter a comma in the dialing string to make the modem pause while dialing. This pause lasts two seconds (North American models) or four seconds (U.K. and International models) for each comma entered. You can force longer pauses by entering multiple commas, or you can change the length of the pause caused by a comma by setting register S8 to any value from 0 through 255 seconds (North American models), 4 through 7 seconds (U.K.
Chapter 3 - AT Commands $ Call Card Tone Detect Use the $ command to dial services that require you to enter your call card number after a tone. A $ character in the dialing string causes the modem to pause and wait for an AT&T call card “bong” or a 1600 Hz tone (prevalent in the U.K.). When the modem detects the tone, it processes the rest of the dialing string. If it does not detect a tone within the time set by register S7 (a 45-second default), the modem aborts with a NO CARRIER message.
Chapter 3 - AT Commands 3.4 Phone Number Memory Commands The modem can store up to two telephone numbers in nonvolatile memory. You can store the numbers with the DsNd command, dial them with the Nd command, link them so that one will be automatically dialed after the other with the NdNe command, or list them with the L command. DsNd Store a Phone Number s = phone number d = 0 or 1 Default: none You can store a telephone number command string of up to 60 characters in the modem’s phone number memory.
Chapter 3 - AT Commands L List Stored Telephone Numbers Use the L command to display dialing commands stored in the modem’s nonvolatile memory. Typing ATL displays the stored N numbers in the following format: 0 T14082345678 1 P9,T14089876543 All digits and command letters are displayed. The N number is shown first, followed by the complete dialing command and telephone number as originally entered.
Chapter 3 - AT Commands 3.5 Configuration Storage and Recall Commands The MT2834MR6 stores parameters in two places. It stores factory default parameters in read-only memory (ROM), and customized parameters in nonvolatile random access memory (NVRAM). You cannot change the default parameters in ROM; however, you can change parameters in temporary memory and then store them in NVRAM as custom settings. You can then recall the custom settings as if they were factory default settings.
Chapter 3 - AT Commands Table 3-2. Where the Modem Reads Configuration Parameters Z Previous Command AT&F Power-On and ATZ AT&W1 (default) AT&W0 AT&F8&W0 AT&F9&W0 ROM ROM ROM NVRAM ROM NVRAM NVRAM NVRAM Reset Modem The Z command resets the modem to its default configuration and clears the command buffer. The result is the same as turning the modem off and on. When you type ATZ, the state of the &W command determines where the default values originate.
Chapter 3 - AT Commands 3.6 Modem Response (Result Code) Commands The MT2834MR6’s modems can give responses to commands. The most common one is OK, but the modems also can alert you or your software to dial tones, busy signals, connection speeds, and whether the connection is made with error correction or compression enabled. These responses are called result codes, and they can be terse or verbose, Multi-Tech or standard, basic or extended.
Chapter 1 - Introduction Vn Result Codes (Verbose/Terse) n = 0 or 1 Default: V1 The V command controls whether the modem’s result codes display as verbal (“verbose”) or digital (“terse”) messages. For example, if no carrier signal is detected after dialing, the result can be displayed either as NO CARRIER, or as the digit 3. V0 (or V) displays the modem’s result codes as digits. V1 displays result codes as words.
Chapter 3 - AT Commands 3.7 Online Connection Commands The following commands control the conditions of the online connection. #An Auto Speed Detection n = 0–3 Default: #A0 An MT2834MR6 modem can operate as a 33,600 bps, 28,800 bps, 19,200 bps, 14,400 bps, 9600 bps, 4800 bps, 2400 bps, or 300 bps modem. Use the #A command to select the speed that the modem uses for initial handshaking and subsequent speed selection.
Chapter 3 - AT Commands &CDn Cleardown at Disconnect n = 0 or 1 Default: &CD0 In the V.32, V.32bis, and V.34 protocols, a cleardown is sent by one of the modems to signal the other modem that it is going to hang up. A cleardown is rate renegotiation in which the modem that is hanging up tells the other modem that it has no speeds that it can connect at. It is designed to help the remote modem detect a hangup. However, it does take a second or two to send the cleardown.
Chapter 3 - AT Commands &Gn Guard Tones n = 0, 1, or 2 Default: &G0 (models outside U.K.) &G2 (U.K. models only) The &G command is used to control the presence or absence of guard tones from the transmitter when in answer mode at either 1200 or 2400 bps. Guard tones are used in Europe and other areas to allow the modem to function in the telephone systems. Guard tones are not used in the United States. U.K. models are locked at &G2 (1800 Hz guard tone). &G0 disables ITU-T guard tones.
Chapter 3 - AT Commands $Tn Calling Tone n = 0 or 1 Default: $T1 The $T command enables or disables the modem’s calling tone, which is required by some European countries to identify the caller as a modem. $T0 enables the calling tone. $T1 disables the calling tone. #Tn Trellis-Coded Modulation n = 0 or 1 Default: #T1 The #T command enables or disables trellis-coded modulation (TCM) on the modem. There is usually no need to disable TCM, except for an unusual line condition called impulse noise.
Chapter 3 - AT Commands 3.8 V.34 Commands The following commands apply only in V.34 mode. %Fn Echo Canceler Frequency Offset Compensation n = 0 or 1 Default: %F0 The %F command enables and disables echo canceler frequency offset compensation which, when enabled, can decrease modem performance. %F0 disables echo canceler frequency offset compensation. %F1 enables echo canceler frequency offset compensation.
Chapter 3 - AT Commands 3.9 RS-232 Interface Commands These commands define how am MT2834MR6 modem will use and respond to standard RS-232 signals. &Cn Carrier Detect Control n = 0, 1, 2, or 4 Default: &C1 The &C command lets you control the Carrier Detect (CD) signal on the RS-232/V.24 interface. Normally, CD goes high when the modem detects a carrier on the communications link, and drops when it loses the carrier.
Chapter 3 - AT Commands &Sn Data Set Ready Control n = 0, 1, or 2 Default: &S1 Use the &S command to control the state of the Data Set Ready (DSR) signal on the RS232/V.24 interface. Normally, DSR follows CD. You can force the signal high; allow it to act normally; or set it to stay high until the modem disconnects, go low momentarily, and then go high again. &S0 forces DSR high. &S1 allows DSR to act normally, that is, to follow CD.
Chapter 3 - AT Commands 3.10 Error Correction and Data Compression Commands You can configure a modem to any of three different V.42 modes of operation (each mode can be with or without compression). They are the non-error correction, autoreliable, and reliable modes. You can also turn data compression on or off. &En Error Correction Modes n = 0, 1, or 2 Default: &E1 Select the modem’s error correction mode using the &E0, &E1, or &E2 command. &E0 disables the modem’s V.
Chapter 3 - AT Commands $En V.42 Error Correction at 300 bps n = 0 or 1 Default: $E0 At 300 bps, error correction is not normally used. $E0 disables 300 bps/V.42 error correction altogether. $E1 enables the modem to function at 300 bps in non-error correction (&E0), autoreliable (&E1), or reliable (&E2) mode. $An Autoreliable Buffering n = 0 or 1 Default: $A0 In autoreliable mode, the modem has four seconds to establish a reliable connection, after which the modem drops to non-error correction mode.
Chapter 3 - AT Commands 3.11 Speed Conversion Commands Speed conversion allows the MT2834MR6 to communicate at a fixed speed through the serial port while communicating at an independent speed over the online communications link. Speed conversion is necessary for data compression, since data compression requires data to be sent from the computer to the modem at a rate up to four times faster than the modem’s transmission speed.
Chapter 3 - AT Commands $SBn Serial Port Baud Rate n = speed Default: $SB57600 The $SB command sets the speed of the MT2834MR6’s serial port in both originate and answer modes. Speed conversion allows you to set this serial port baud rate at a fixed speed of up to 115,200 bps, regardless of the modem’s transmission speed setting. For this command to work, the modem’s baud adjust feature must first be turned off with the $BA0 command.
Chapter 3 - AT Commands 3.12 Immediate Action Commands Use these commands to get information about AT commands and the current settings of the modem. For additional immediate action commands, see “Line Probe Commands.” A/ Repeat Last Command Default: None Type A/ to repeat the previous command. Do not precede this command with AT or press ENTER to execute it.
Chapter 3 - AT Commands &RN Rate Renegotiation Default: none The &RN command forces the modem to perform a rate renegotiation while online. To issue it, you must first escape to command mode by issuing the +++AT command. &RR Retrain Default: None The &RR command forces the modem to perform an immediate retrain while online. To issue it, you must first escape to command mode by issuing the +++AT command.
Chapter 3 - AT Commands 3.12 Flow Control Commands Flow control refers to the techniques used by data terminal equipment and the modem to pause and resume the flow of information between them. It prevents a device from accepting more data than it can handle. The modem implements flow control in both directions. When the modem halts the flow of data, it is called flow control, and when the computer halts the flow, it is called pacing.
Chapter 3 - AT Commands &E5 XON/XOFF Flow Control XON/XOFF flow control is an in-band method of data flow regulation used by the modem or computer (i.e., by flow control or pacing). If you issue the &E5 command to the modem, it will respond to XON/XOFF pacing, and use XON/XOFF characters as its own method of flow control to the computer. In-band data regulation means that the XON and XOFF characters (^Q and ^S, respectively) are inserted into the stream of data rather than using separate control lines.
Chapter 3 - AT Commands &En Pacing (Computer-Initiated Flow Control) n = 12 or 13 Default: &E13 Pacing is the means by which the DTE (data terminal equipment—your computer or terminal) regulates the stream of incoming data. It is only enabled when the modem has some form of flow control active, such as RTS/CTS or XON/XOFF. When pacing is enabled, the modem responds to the DTE’s pacing signals. When pacing is disabled, the modem ignores any pacing signals from the DTE. &E12 disables pacing.
Chapter 3 - AT Commands 3.13 Escape Sequences Escape sequences (escape codes) cause the modem to enter command mode from online mode without disconnecting the call. There are two local escape sequences used by the modem, +++AT and AT, and one remote escape sequence, %%%AT (see “Remote Configuration”). +++AT In-Band Escape Sequence When the modem is online with a remote modem, enter command mode (without disconnecting the call) by typing this escape code.
Chapter 3 - AT Commands 3.14 Remote Configuration Commands When you are online with another Multi-Tech modem, you can issue AT commands to it by sending a remote configuration escape sequence. The remote modem responds by displaying a menu and asking for a setup password. The MT2834MR6 has two default passwords. Please note that if you change them, you cannot retrieve them by resetting the modem by using AT&W1; you must know the new passwords to make any further changes.
Chapter 3 - AT Commands 3.15 Line Probe Commands Before V.34 negotiation, the local and remote modems use modulated calling and answering tones to exchange capability information . If V.34 mode communication is successful, probing signals are exchanged to identify impairments in the telephone channel. Using the results of these line probes, communication parameters are set, including carrier frequencies and data rates used for transmission. The following commands apply to modems only in V.34 mode.
Chapter 3 - AT Commands 3.16 Diagnostic Commands The MT2834MR6 has two diagnostic commands and four diagnostic modes. The power-on self-test is activated every time power is applied. The U command selects a loopback test, while the &T command enables a modem to respond to a loopback test from another modem. See Chapter 6, “Testing the MT2834MR6,” for a fuller discussion. Refer to the L8 command to see how to list the diagnostic online status.
Chapter 4 - S-Registers
Chapter 4 - S-Registers 4.1 Introduction This chapter describes the MT2834MR6’s S-registers, which are small regions of memory where modem configuration information is stored. Whereas AT commands tell a modem what to do, S-registers tell the modem how to do it. Each S-register has a name that consists of the letter S and a number (S0, S1, S2, etc.), hence the term S-register. Use the Sr? command to read the value stored in an S-register, and the Sr=n command to change it. 4.
Chapter 4 - S-Registers S3 Return Character Unit: Decimal Range: 0–127 Default: 13 (^M) S3 defines the carriage return character by its decimal ASCII code. The default setting is the ^M character (decimal 13), which is the code for the ENTER key on most keyboards. S3 may be set for any ASCII character. Note: If you change the S3 value, you must make corresponding changes in your data communications software.
Chapter 4 - S-Registers S7 Time for Carrier (Abort Timer) Unit: 1 second Range: 1–255 (U.S.A.) 1–45 (Canada and International) 1–55 (U.K.) Default: 45 (North America and International) 55 (U.K.) S7 determines the abort timer delay time, which is the amount of time your modem will wait for a carrier signal before it disconnects. The default value is 45 seconds, except the U.K. model, for which it is 55 seconds.
Chapter 4 - S-Registers S11 Tone Dialing Spacing and Duration Unit: 1 ms Range: 1–255 (U.S.A.) 80–255 (Canada, U.K., International) Default: 70 (U.S.A.) 80 (Canada, U.K., International) S11 sets the speed of tone dialing (spacing and tone duration times). The default value is 70 units for domestic models and 80 units for Canadian and International models, where each unit is one ms. In other words, for domestic modems, each tone is sustained for 70 ms followed by a 70 ms pause.
Chapter 4 - S-Registers S30 Inactivity Timer Unit: 1 minute Range: 0, 1–255 minutes Default: 0 (disabled) S30 can be used to cause the modem to disconnect if no data is transmitted or received for a specified time. S30 runs during both reliable and non-error correction connections. The timer restarts any time a data character passes through the serial port (either sent or received).
Chapter 4 - S-Registers S43 Force V.34 Connect Speed Unit: N/A Range: 0, 33, 31, 28, 26, 24, 21, 19, 16, 14, 12, 96, or 48 Default: 0 (disabled) S43 forces the modem to attempt to connect at a fixed speed in V.34 mode. The two-digit value corresponds to the first two digits of the speed (S43=21 sets the connect speed to 21.6K bps, S43=96 sets it to 9600 bps, etc.). The factory default of zero disables this feature and allows the modem to establish the best speed for the conditions.
Chapter 4 - S-Registers 4.3 Reading and Assigning S-Register Values Use the S command to assign a value to an S-register and to read an S-register’s current value. To read an S-register value, in terminal mode, type S, the S-register number, and a question mark (?), and press ENTER. For example, to display the value of register S7, type ATS7? and press ENTER. The answer will appear as a three-digit decimal number (e.g., 045).
Chapter 4 - S-Registers 4.4 AT Commands Affecting S-Registers For maximum throughput, the MT2834MR6's default configuration is for originating a call to another 33,600 bps modem that supports error correction, data compression, and flow control. If the receiving modem is not compatible, the MT2834MR6 can match any ITU-T or Bell standard modem (but not proprietary protocols).
Chapter 5 - Error Correction, Data Compression & Speed Conversion
Chapter 5 - Error Correction, Data Compression, and Speed Conversion 5.1 Introduction The MT2834MR6 has intelligent features beyond those of the AT command set described in Chapter 3. This chapter describes high performance features and commands that provide error correction, data compression and speed conversion capabilities. The remainder of this chapter describes these features and the commands that implement them, as well as related commands.
Chapter 5 - Error Correction, Data Compression, and Speed Conversion 5.2 How V.42 Detects and Corrects Errors Some of the better known software-based error-correction protocols include Xmodem and Kermit (for asynchronous file transfer software), X.PC (Tymnet’s asynchronous software protocol), and SDLC and HDLC, two popular synchronous protocols common in the IBM mainframe environment. V.42 is functionally similar to SDLC and HDLC, with some extras. The main advantage of hardware-based V.
Chapter 5 - Error Correction, Data Compression, and Speed Conversion 5.3 Data Compression The MT2834MR6 has both V.42bis and MNP class 5 data compression. ITU-T V.42bis is an international data compression standard that can provide data compression of up to four to one in certain types of data. MNP class 5 is a proprietary technique for data compression that provides a data compression capability of two-to-one.
Chapter 5 - Error Correction, Data Compression, and Speed Conversion 5.5 V.42 Mode Select Command (#L) The V.42 Mode Select command (#L) selects which type of error correction your MT2834MR6 will use for transmissions. The V.42 standard implements both MNP Class 3 & 4 and LAP-M error correction protocols. When you execute one of the #L commands, you instruct your MT2834MR6 how to operate with each protocol.
Chapter 5 - Error Correction, Data Compression, and Speed Conversion 5.6 Modes of Operation You can configure your MT2834MR6 in one of three different V.42 modes of operation, each with or without compression. They are the non-error correction, reliable, and autoreliable modes. The modes and data compression features are selected with commands described later in this chapter in “Compression, Error Correction, Flow Control, Pass Through, and Pacing Commands.” 5.6.
Chapter 5 - Error Correction, Data Compression, and Speed Conversion 5.7 Flow Control Flow control refers to the techniques used by computer devices to stop and restart the flow of data from each other. Flow control is necessary so that a device does not receive more data than it can handle. In the case of the MT2834MR6, there is a need for flow control in both directions.
Chapter 5 - Error Correction, Data Compression, and Speed Conversion 5.8 Modem-Initiated Flow Control When operating in V.42 reliable mode, the MT2834MR6 stores data in a buffer as it is received. During periods of error-caused retransmissions or compression slowdowns, this buffer may fill up. To prevent buffer overflow and subsequent loss of data, the modem uses flow control to signal the computer attached to its RS232 port that the modem buffer is close to being full.
Chapter 5 - Error Correction, Data Compression, and Speed Conversion 5.9 Pacing (&E13) As mentioned earlier, the MT2834MR6 can initiate flow control by issuing XON/XOFF commands or by toggling the CTS signal on the RS-232 interface. The modem can also be configured to react to similar commands and signals from the computer or terminal to which it is connected by the RS-232 interface. Pacing is computer-initiated flow control.
Chapter 5 - Error Correction, Data Compression, and Speed Conversion 5.10 Compression, Error Correction, Flow Control, and Pacing Commands The MT2834MR6 has several commands that control error correction, data compression, and flow control: 5.10.1 V.42 Error Correction Modes &E0 Non-auto correction mode (no error correction). &E1 Autoreliable mode (factory default). &E2 Reliable mode. 5.10.2 Modem-Initiated Flow Control &E3 Disable flow control.
Chapter 5 - Error Correction, Data Compression, and Speed Conversion 5.11 Result Codes When the MT2834MR6 connects with another modem with error-correction or data compression enabled, its CONNECT responses change to inform you of the type of connection. (See Appendix C for a complete list of result codes.) 5.11.1 MNP Error Correction If terse responses are enabled, an R is added to the numeric code. If verbose responses are enabled, the word RELIABLE follows the CONNECT message. 5.11.
Chapter 5 - Error Correction, Data Compression, and Speed Conversion 5.12.1 Baud Adjust ($BA) In typical operations, the MT2834MR6 will do one of two things regarding speed. It will automatically match the speed of its RS-232 interface and phone line transmissions to that of the terminal or computer to which it is connected as soon as it receives its first AT command. Or, in autoanswer mode, it will match its RS-232 and transmission speeds to that of the originating modem that called it.
Chapter 5 - Error Correction, Data Compression, and Speed Conversion 5.12.3 Serial Port Baud Rate ($SB) The $SB command presets the speed of the MT2834MR6’s RS-232 serial port in both the originate and the answer modes. Speed conversion allows you to set this serial port baud rate at a fixed speed of up to 115,200 bps, regardless of the modem’s transmission speed setting.It also sets the default speed at which the modem issues command responses (result codes).
Chapter 5 - Error Correction, Data Compression, and Speed Conversion 5.13 Related Commands 5.13.1 Autoreliable Buffering ($A) In autoreliable mode, the modem is given four seconds to establish a reliable connection. If it cannot establish a reliable connection in that time, the modem drops to non-error correction mode. Any data received during this period is normally discarded. The $A command is used to cause the modem to buffer (save) data that is received during the autoreliable time-out period.
Chapter 5 - Error Correction, Data Compression, and Speed Conversion 5.13.4 Retransmit Count ($R) If errors are received during a reliable connection, the modem resends the block of data that contained errors. If another error occurs, the block is re-sent again. The modem counts the number of times that a data block is re-sent. If the same block of data is re-sent 12 times and still has not been received properly, the modem aborts the connection, as dictated by the AT$R0 command.
Chapter 6 - Testing & Troubleshooting
Chapter 6 - Testing and Troubleshooting 6.1 Introduction Each time you power up the MT2834MR6, it performs an automatic self-test to ensure proper operation. The MT2834MR6 also has three diagnostic tests: local analog loopback, digital loopback (remote/automatic), and digital loopback (local/manual). These ITU-T V.54 loopback tests isolate telephone circuit and transmission problems.
Chapter 6 - Testing and Troubleshooting 6.2 Local Analog Loopback Test (V.54 Loop 3) In this test, data from your computer or terminal is sent to your modem’s transmitter, converted into analog form, looped back to the modem’s receiver, converted into digital form, and then sent to your monitor for verification. No connection to the phone line is required. See Figure 6-1. Figure 6-1. Local analog loopback test. 6.2.1 Test Procedure 1. Connect the modem to your computer.
Chapter 6 - Testing and Troubleshooting 6.3 Remote Digital Loopback Test (V.54 Loop 2) In this test, your modem must be online with another modem, such as another ZDX, that is set up to respond to a request for remote digital loopback. With the ZDX, this ability to respond is controlled by the &T command. AT&T4 enables the response to remote digital loopback; AT&T5 disables the response.
Chapter 6 - Testing and Troubleshooting 6.4 Local Digital Loopback Test (V.54 Loop 2) This test is identical to the remote digital loopback test with one exception. Instead of using your modem to signal a remote modem to place itself in digital loopback mode, your modem is placed in digital loopback mode while the remote modem is not. Data is entered and transmitted from the remote modem, sent across the phone line to the local modem, and looped back to the remote modem. See Figure 6-3. Figure 6-3.
Chapter 7 - Warranty & Service
Chapter 7 - Warranty And Service 7.1 Multi-Tech Systems, Inc. Warranty & Repairs Policies 7.1.1 Warranty Multi-Tech Systems, Inc., (hereafter “MTS”) warrants that its products will be free from defects in material or workmanship for a period of two, five, or ten years (depending on model) from date of purchase, or if proof of purchase is not provided, two, five, or ten years (depending on model) from date of shipment.
Chapter 7 - Warranty And Service 7.1.3 International Customers (outside U.S.A. and Canada) Your original point of purchase reseller may offer the quickest and most economical repair option for your Multi-Tech product. You may also contact any Multi-Tech sales office for information about the nearest distributor or other repair service for your Multi-Tech product: www.multitech.com.
Chapter 7 - Warranty And Service 7.2 Repairs 7.2.1 Repair Procedures for U.S. and Canadian Customers In the event that service is required, products may be shipped, freight prepaid, to our Mounds View, Minnesota factory: Multi-Tech Systems, Inc. 2205 Woodale Drive Mounds View, MN 55112 Attn: Repairs, Serial # ____________ A Returned Materials Authorization (RMA) is not required. Return shipping charges (surface) will be paid by MTS.
Chapter 7 - Warranty And Service 7.2.3 Repair Procedures for International Distributors Procedures for International Distributors of Multi-Tech products are on the distributor web site: www.multitech.com 7.2.4 Replacement Parts SupplyNet, Inc., can supply you with replacement power supplies, cables and connectors for selected MultiTech products. You can place an order with SupplyNet via mail, phone, fax or the Internet at the following addresses: Mail: SupplyNet, Inc.
Appendices
Appendix Appendix A ASCII Conversion Chart CTRL CODE HEX DEC @ A B C D E F G H I J K L M N O P Q R S T U V W X Y Z [ \ ] ^ _ NUL SOH STX ETX EOT ENQ ACK BEL BS HT LF NUL SOH STX ETX EOT ENQ ACK BEL BS HT LF VT FF CR SO SI DLE DC1 DC2 DC3 DC4 NAK SYN ETB CAN EM SUB ESC FS GS RS US 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F 10 11 12 13 14 15 16 17 18 19 1A 1B 1C 1D 1E 1F 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 Null, or all zeros Start of Header Start of
Appendix Appendix B Dial Pulses When you pulse dial, as when you make a call with a rotary dial telephone, your telephone or modem generates codes in the form of pulses that simulate the opening and closing of old-fashioned electric relays, or switches. The number of pulses in a code are the same as the digit they encode; thus, the digit 1 is represented by one pulse, the digit 2 by two pulses, etc. In Figure B-1, the digit 2 is pulse dialed, followed by the digit 1.
Appendix Tone Dial Frequencies The tone dialing method combines two frequencies for each of the twelve digits found on a touch-tone dial pad. This method is referred to as dual-tone multi-frequency (DTMF) dialing. The four horizontal rows on a touch-tone keypad use four low-frequency tones (697, 770, 852, 941 Hz), while the three vertical columns use three high-frequency tones (1209, 1336, 1477 Hz). The tone frequency tolerance is ± 0.02%.
Appendix Appendix C Result Code Summary Multi-Tech Result Codes (&Q0 ) Terse Verbose Definition 0 1 2 3 4 5 6 7 8 9 10 11 12 13 19 21 23 OK CONNECT RING NO CARRIER ERROR CONNECT 1200 NO DIALTONE BUSY NO ANSWER CONNECT 2400 CONNECT CONNECT CONNECT CONNECT CONNECT CONNECT 4800 9600 14400 19200 21600 1275 Command was executed without error; ready for next command. Modem has detected carrier and gone online. Modem has detected ring caused by incoming call.
Appendix LAP-M Reliable Mode. If the modem connects using LAP-M error correction, the word LAPM or letter L is added to the CONNECT responses as follows: 1L 5L 9L 10L 12L 13L 19L 21L 24L 26L 28L 31L 33L CONNECT CONNECT CONNECT CONNECT CONNECT CONNECT CONNECT CONNECT CONNECT CONNECT CONNECT CONNECT CONNECT LAPM 1200 LAPM 2400 LAPM 4800 LAPM 9600 LAPM 14400 LAPM 19200 LAPM 21600 LAPM 24000 LAPM 26400 LAPM 28800 LAPM 31200 LAPM 33600 LAPM Data Compression.
Appendix Appendix D S-Register Summary Register Unit Range S0 1 ring 0, 1–255 1 Sets the number of rings until the modem answers. ATS0=0 disables auto answer completely. S1 1 ring 0–255 0 Counts the rings that have occurred. S2 decimal 0–127 43 (+) Sets ASCII code for the escape code character. S3 S4 decimal 0–127 13 (^M) Sets ASCII code for the RETURN character. decimal 0–127 10 (^J) Sets ASCII code for the LINE FEED character.
Appendix S34 1 char- 0–60 acter 10 Sets the number of command characters allowed after +++AT. S36 1 sec 0, 1-255 5 Sets the time between DTR inactive and modem off-hook. S36=0 disables DTR busy-out. S37 1 sec 0-255 5 Sets the time between DTR active and modem on-hook. S43 decimal 33, 31, 0 Sets fixed V.34 connect speed. 28, 26, 28 = 28800 bps; 26 = 26400 bps;. . . 24, 21, 48 = 4800 bps. 0 default disables this feature. 19, 16, 14, 12, 96, or 48 S48 decimal 33, 31, 0 Sets maximum V.
Appendix Appendix E AT Command Summary Command Values Description AT n/a Attention Code The attention code precedes all command lines except A/, A: and escape codes. RETURN n/a RETURN Key Press the RETURN (ENTER) key to execute most commands. A n/a Force Answer Mode Answer call immediately without waiting for ring. A/ n/a Repeat Last Command Do not precede this command with AT. Do not press RETURN to execute. A: n/a Continuous Redial Continuous redial of last number until answered.
Appendix &CDn n = 0 or 1 Ds s = phone # Dial Dial telephone number s, where s may include up to 60 digits or T, P, R, comma, colon, and semicolon characters. DsNd s = phone # d = 0 or 1 Store Phone Number To store, enter D followed by telephone number s, then N followed by directory number d. &Dn n = 0, 1, 2, or 3 Data Terminal Ready Control &D0 Modem ignores DTR signal. &D1 When DTR drops, the modem hangs up.
Appendix &En n = 0–15 V.42 Error Correction Modes &E0 Non-error correction mode (V.42 disabled). *** &E1 Auto-reliable mode. &E2 Reliable mode (V.42 enabled). Modem-Initiated Flow Control &E3 Flow control disabled. *** &E4 Hardware flow control. &E5 XON/XOFF flow control. XON/XOFF Pass-Through (&E5 selected) *** &E6 XON/XOFF not passed through. &E7 XON/XOFF passed through. Hewlett-Packard ENQ/ACK Pacing *** &E8 ENQ/ACK pacing off. &E9 ENQ/ACK pacing on.
Appendix #Fn n = 0, 1, or 2 Fallback Modes When Online #F0 No fallback when online. #F1 Fall back incrementally from maximum speed to 4800 bps. *** #F2 Fall back incrementally to 4800 bps, fall forward when line improves. &Gn n = 0, 1, or 2 Guard Tones (International model only) *** &G0 Turn off ITU-T guard tones. &G1 Turn on ITU-T 550 Hz guard tone. &G2 Turn on ITU-T 1800 Hz guard tone. Note:The U.K. model is locked to &G2 , which turns on the ITU-T 1800 Hz guard tone.
Appendix $MBn n = speed Nd d = 0 or 1 Dial a Stored Number Dial stored telephone number d. NdNe... d = 0 or 1 e = 1 or 0 Number Linking Dial stored number d; if that is busy, dial stored number e. The command may be extended NdNeNdNe... to cycle between the two numbers. O n/a Go Back On Line Exit command mode and go into online mode after using the escape code to do the reverse. P In dialing command *** Pulse-Dial Modem pulse-dials numbers that follow P.
Appendix &RFn n = 0 or 1 &RN n/a Rate Renegotiation Forces the modem to renegotiate the data rate. &RP n/a Immediate Line Probe Initiates a retrain that makes the modem read line probe information if %DP1 is selected. Valid only when online in V.34 mode. &RR n/a Retrain Initiates an immediate retrain without a line probe reading.
Appendix &Tn n = 4 or 5 Respond to Remote Digital Loopback Signal &T4 Enable response to remote digital loopback signal. *** &T5 Disable response to remote digital loopback signal. $Tn n = 0 or 1 Calling Tone $T0 Enable calling tone. *** $T1 Disable calling tone. #Tn n = 0 or 1 Trellis-Coded Modulation #T0 Disable trellis-coded modulation. *** #T1 Enable trellis-coded modulation. Un n = 0–3 Vn n = 0 or 1 Result Codes (Verbose/Terse) V0 Result codes sent as digits (terse response).
Appendix : At end of dial command Continuous Redial Colon; causes continuous redial of number until answered (10 in North American models). Not used in U.K. or International models. ; At end of dial command Return to Command Mode After Dialing Semi-colon; causes immediate return to command mode after dialing. ! In dial command Flash On-Hook Exclamation; causes modem to flash on-hook.
Appendix Appendix F RS-232C Interface Specifications The MT2834MR6’s serial interface circuits have been designed to meet the electrical specifications in EIA (Electronic Industries Association) Recommended Standard 232, Revision C (RS-232C). All signals generated by the modem are approximately 10 volts when measured across a load of 3000 ohms or greater. The receiving circuits of the modem accepts signals in the 3 to 25 volt range.
Appendix Functional Description of the RS-232C Signals Transmitted Data (TD) — Pin 2 (To modem) Signals on this circuit are generated by the local computer and passed to the modem’s transmitter. A positive signal is a space (binary 0) and a negative signal is a mark (binary 1). The transmitting computer should hold this line in the marking state when no data is being transmitted, including intervals between characters or words. The TD LED indicates the status of this circuit.
Appendix Test Voltage (+V) — Pin 9 (From modem) This test pin has 330 ohms of resistance to +12 volts DC. It can be used to strap other signals high. For example, if the terminal does not supply a DTR (Data Terminal Ready) signal, pin 9 can be jumpered to pin 20 (DTR) on the RS-232C connector or cable to force DTR on. High Speed (HS) — Pin 12 (From modem) The high state of this circuit indicates that the modem is in the high speed (1200 bps) mode.
Appendix Ring Indicator (RI) — Pin 22 (From modem) This signal remains on for the duration of the ringing signal. When a ring signal is received by the modem, the modem automatically answers after the first ring. The modem can answer after a specified number of rings which can be programmed in command mode, but if none is specified, the modem answers after the first ring. External Transmit Clock (XTC) — Pin 24 (To modem) Supplies the same function as the Transmit Clock signal on pin 15.
Appendix Appendix G Cable and Connector Diagrams RS-232C Serial Cable 1 2 3 4 5 6 7 8 9 12 15 17 20 22 25 1 2 3 4 5 6 7 8 9 12 15 17 20 22 25 Frame Ground Transmit Data Receive Data Request to Send Clear to Send Data Set Ready Signal Ground Carrier Detect + Voltage Test High Speed Transmit Clock Receive Clock Data Terminal Ready Ring Indicator Terminal Busy 1 2 3 4 5 6 7 8 9 12 15 17 20 22 25 25-pin male connector (DB-25P) 25-pin female connector (DB-25S) on back of rack Connects to terminal or comput
Appendix APPENDIX H Introduction to MultiTech Escape Methods You may sometimes find it necessary to issue AT commands to your modem, while you are online with a remote modem, without disconnecting the call. If so, you will want to take advantage of escape methods that allow you to change the modem’s mode of operation from online mode to command mode. After you issue your AT commands, you may return to online mode, but typically most users escape so that they can hang up a modem upon completion of a call.
Appendix How to Select an Escape Method If you want your modem to escape and then wait for you to issue a command before it will return to online mode, then use +++AT. For example, use this method if you find you need to review a help screen in the middle of a communications session. If you wish to combine the escape with a command (or commands) and with an immediate return to online mode, then use the AT method.
Appendix S-Registers and Escape Sequence There are two S-registers to modify the functioning of escape sequences. Register S32 establishes a value for how much time may elapse between the receipt of the beginning of the escape sequence, whether AT or +++AT, and the receipt of a . This interval is known as wait-for--time, or break passthrough. Assign a value in increments of 100 milliseconds to S32. The default value is 20, or 2 seconds.
Appendix APPENDIX I Introduction to Remote Configuration Remote configuration, a feature of Multi-Tech’s MT2834MR6 modems, is a network management tool that allows you to configure modems anywhere in your network from one location. With password-protected remote configuration, you can issue AT commands to a remote Multi-Tech modem for maintenance or troubleshooting as if you were on site.
Appendix Changing the Passwords 1. Establish a remote configuration link with the remote modem as described above. 2. Type AT#IMULTI-TECH (or AT#Ixxxxxx if you have replaced the MULTI-TECH password with xxxxxx) and press ENTER. The modem responds with OK if the login password is correct, and ERROR if it is wrong. 3. Type AT#SMODEMSETUP (or AT#Syyyyyy if you have replaced the MODEMSETUP password with yyyyyy) and press ENTER.
Index
Index Index A Abort timer 19, 21, 28, 29, 59, 63 Analog loopback test 82 Answer command 21, 52 Answer mode 27, 46, 52 Answer Tone command 36 Answerback command 35 Answering a call 52, 63 Asymmetric Bit Rate command 40 Asynchronous Word Length command 49 AT Command Control command 21, 36 AT Command Summary 98 AT commands 21 , (comma) 28, 59 ! (exclamation mark) 28 #A 36 #F 37 #I 53 #L 43 #S 53 #T 39 #V 40 #X 51 $ 29 $A 44, 78 $BA 45, 46, 76, 77 $E 44, 79 $EB 49 $F 44, 78 $MB 36, 45, 76 $R 44, 79 $SB 46, 77
Index A: 26 AT 21, 22 attention code 21, 22 B 36 command string limit 22 D 21, 26 D...N... 30 disabling command mode 21, 36 E 34 editing 22 functional summary 23, 24, 25 H 19, 26 I 47 L 31 L10 54 L11 54 L5 47, 64 L6 47, 64 L7 47, 64 L8 47, 55 L9 54 N 30 N...N...
Index CTS signal control of 41 disconnect drop time 60 flow control 49 RTS interaction 42 CTS/RTS interaction control 42 D DAA 9 Data bit 49 Data compression 66, 68, 74 speed conversion 45 Data Compression command 43 Data Set Ready Control command 42 Data Terminal Ready Control command 41 Description of MT2834MR6 9 Diagnostic commands 55 Dial a Stored Number command 30 Dial command 21, 26 Dial pulses 92 Dial tone 26 wait time 35, 58 Dial tone frequencies 93 Dialing a phone number 26 a stored number 30 auto
Index Flash On-Hook command 28 Flow control 41, 49, 50, 51, 74 commands 49 CTS/RTS enable 49 disabling 49 hardware (RTS/CTS) 72 no-error correction mode 73 non-error correction mode 50 software (XON/XOFF) 72 XON/XOFF pass through 50 Flow Control Disable command 49 Format Line Probe Data command 54 Fuses 14 G Go Back Online command 52 Guard Tones command 38 H Handshake 18, 36 Hanging up 19, 26, 111 Hardware Flow Control command 49 I Immediate Line Probe command 54 Inactivity timer 19, 61 Indicators 15 Ind
Index P Pacing 49, 50, 73 enable/disable 51 ENQ/ACK 50, 73 Pacing command 51, 74 Parameters 22, 32, 47 default 22, 41 Parity 49 PBX phone systems 27, 60 PBX/CBX disconnect drop time 41, 42, 60 Power 14 Pulse ratios, setting 92 Pulse-Dial command 27 Pulse-Dial Ratios command 38 Q Quiet Answer command 28 R Rate Renegotiation command 48 RD signal 15 Read Line Probe Data command 54 Reliable mode 43, 49 Reliable Mode command 43, 70 Remote configuration escape character 60 Remote Digital Loopback command 55 Rep
Index S9 59 S94 38, 62 summary 96 Safety 16 Serial port baud rate 46 Serial Port Baud Rate command 77 Set Pulse Dial Ratios command 92 Setup Password command 53 Smart dialing 26, 28, 35 Specifications 12 Speed conversion 45, 46, 66, 75 Speed, data transmission 15 Speed indicator 15 Square Wave Ring Detect command 38 Start bit 49 Stop bit 49 Store Configuration command 32, 33, 64 Store Phone Number command 30 Storing a configuration 32, 63 T asymmetric bit rate 40 connect speed 62 echo canceler frequency o
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