Multi-Tech Systems BA-Series Speed Conversion Commands, Speed Conversion $BA, Modem Baud Rate $MB

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MultiModemBA User Guide

4.4.11Speed Conversion Commands

Speed conversion is a necessary part of data compression since data must be presented to the modem faster than it can handle data, if data compression is to be effective.

Speed conversion allows the modem to communicate at one speed over the phone line, and at another speed at the RS-232C interface. The speed (also referred to as “data rate” or “baud rate”) can be fixed at the RS-232 interface independently of the baud rate of the on-line transmissions.

In addition to data compression, another popular application for speed conversion involves an auto- answer MultiModem connected to a computer that does not have autobaud capability. This means that the computer must be set at a fixed baud rate, regardless of the baud rate that the modem is communicating over the phone line at. In this application, speed conversion allows the modem to match its speed to that of the calling modem, while at the same time communicating with the attached computer through its RS-232C port at a fixed baud rate, which can be pre-selected at 300, 1200, 2400, 4800, 9600, 19,200, 38,400, 57,600 bps or 115,200 bps.

Speed Conversion $BA

When using speed conversion, you must set the modem so that it does not adjust its speed at the RS-232C serial port, even if the modem does adjust its data rate. To turn Speed Conversion ON, enter the command AT$BA0 and hit RETURN.

To turn Speed Conversion OFF, enter AT$BA1 and hit RETURN. The modem will now match its RS- 232C speed to that of the computer, and will adjust its speed to any changes in the computer’s speed in Originate mode, or to the speed of the originating modem in Answer mode. The speed at which the modem communicates over the phone line will always be the same as the speed at which it communicates via its RS-232C serial port.

Modem Baud Rate $MB

The $MB command presets the modem’s transmission baud rate for originate operations, (i.e., the speed of the modem’s transmissions over the telephone lines when originating a call). With speed conversion, this transmission speed can be a different baud rate than the serial port speed.

When the modem receives (answers) a call from another modem, it automatically switches its phone line transmission speed to match the calling modem. However, if the modem originates a call to another modem that is unable to connect at the same baud rate, it automatically drops to a lower baud rate in an attempt to match the speed of that modem. For example, if the modem is set for 14,400 baud and calls another modem that has a top speed of 2400 baud, it drops to 2400 baud.

The command to set the Modem Baud Rate is AT$MBn, where n can be:

AT$MB75

AT$MB300 AT$MB1200 AT$MB2400 AT$MB4800 AT$MB9600 AT$MB14400 AT$MB19200 AT$MB28800 AT$MB33600

=CCITT V.23

=300 bps

=1200 bps

=2400 bps

=4800 bps

=9600 bps

=14400 bps

=19200 bps

=28800 bps

=33600 bps

The factory default is 33600 bps.

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Contents User Guide User Guide Record of RevisionsContents Index 106 Introduction and Description How To Use This Manual IntroductionModem Features Callback and Remote ConfigurationDIP-Switches Warranty, Service & Technical Support1 2834 Series Features Fax FeaturesTechnical Specifications Power Modem LED Indicators MT2834 LED DisplayControls on PC Board Installation and Connection What is in Your Modem Package? InstallationSafety Warnings Installation ProcedureInstallation and Connection Step ProcedureInstalling Data Communications Software MultiModemBA/BAI ConnectionsSoftware Configuration and Modem Basics Configuring Your Software Configuring Software for Your ModemPC Initialization Strings AT &F X4 S0=0 MChanging Default Parameters Configuring Software for Your ComputerConfiguring Software for the Remote System Other ParametersTerminal Emulation File Transfer ProtocolsCommand Mode AT Command Editing Functional ModesSummary of AT Commands Command ModeStore Modem Configure Data Standard AT Result Codes Result CodesMulti-Tech Result Codes Dialing Commands Dialing Action Commands Dial Command DContinuous Redial not used in BAI a or Dialing a Stored Number NDial Modifier Commands DTR Dialing $DVoice/Data Dialing $VD Pulse or Tone Dial P TReturn to Command Mode After Dial Command Execution Reverse the Mode of Operation RSet Pulse Dial Ratios &P Automatic Pauses in DialingPhone Number Memory Commands Flash On HookCalling Card Detect Tones $ Quiet Answer @Listing Numbers Stored in Memory L Configuration and Default Storage CommandsNumber Linking NN Loading Factory Defaults &F Modem Reset ZAsync/Sync Mode Switching &M Unix Uucp Spoofing $SPCommand Response Result Code Commands Echo Command Mode Characters EResult Codes Enable/Disable and No Response Answer Q Result Codes Multi-Tech or Standard AT &QGuard Tones Not Used in BAI Models &G Phone Line Conditioning CommandsResult Codes Basic and Extended and Call Progress Selection Enable/Disable Trelis Coded Modulation #T Fallback Modes When On-Line #FBell/V.21 Tone Phone Line Monitoring Speaker M7 RS-232C Interface Control Commands Enable/Disable Lowspeed Fast Connect $FCCleardown at Disconnect &CD Auto Speed Detect #AData Terminal Ready Control &D CTS Control &RData Set Ready Control &S CTS/RTS Interaction Control &RFError Correction Commands Enable/Disable Auto Reliable Fallback Character $F Auto-Reliable Buffering $ARetransmit Count $R Flow Control CommandsError Correction/300bps $E Xon/Xoff Pass-Through &E7 Hardware Flow Control &E4 Xon/Xoff Flow Control &E5 Normal Mode Modem Flow Control On &E11 Send Xon/Xoff Characters #XHewlett-Packard ENQ/ACK Pacing &E9 Terminal/Computer Initiated Pacing &E13Normal/Auto-Reliable/Reliable Mode Commands Xon/Xoff Pass-Through CommandsEnq/Ack Pacing Commands Parity Selection #PModem Baud Rate $MB Speed Conversion CommandsSpeed Conversion $BA Serial Port Baud Rate $SB Immediate Action Commands Force Answer Mode a Off Hook HLine Probe Commands Exiting Command Mode, Going Back On-Line OEnable/Disable Reading of Line Probe Information Commands Format of Line Probe Graph or Table CommandsRegisters Number of Rings Until Modem Answers Rings Which Have OccurredEscape Code Character Return CharacterTime for Carrier Abort Timer Line Feed CharacterBackspace Character Wait Time for Dial ToneS10 Carrier Loss Disconnect Delay Time S13 Remote Configuration Escape CharacterCarrier Detect Response Time S11 Tone Dialing Tone Spacing and DurationS15 Callback Time Delay S16 Callback AttemptsS17 Changing Break Time S24 PBX/CBX Disconnect Drop Time for DSR/CTS/CDS26 Failed Password Attempts S29 Local Inactivity TimerS30 Inactivity Timer S32 Time Elapse for Escape SequenceReading and Assigning S-Register Values S36 Time Between DTR Inactive and Modem Off-HookS37 Time Between DTR Active and Modem On-Hook S48 Program V.34bis Connect Speeds 2834 Series onlyExamples of Reading Values AT Command and S-Register SummaryExamples of Assigning Values Callback Security and Remote Configuration Callback Feature Description Remote Configuration DescriptionTo set parity of the password/message prompt To change your Remote Configuration feature statusTo turn your modems Callback Security feature on and off AT#DB2CR or AT#DB1CR Remote Configuration Procedures Callback Security and Remote ConfigurationCallback Operational Sequence Procedures Remote Configuration Operation Procedures StepProcedureRemote Configuration and Callback Security AT Commands Callback Security Enable/DisableChange Login Password AT#I=yyyyyyyyyyCRRemote Configuration/Callback Security S-Registers Local Inactivity Timer S29 DIP-Switch Settings DIP-Switch Option Settings PC BoardSwitch #4 AS/400 Mode Synchronous Mode/Leased Line/Dial-UP DIP-Switch SettingsMultiModemBA User Guide = Down Down Speaker Volume Control Switch #16 Reserved for Future UseRecording Option Configurations Switch Function Position EffectDIP Switches #13-14 DIP Switches #15-16Warranty, Service and Tech Support Multi-Tech Systems, Inc. Warranty & Repairs Policies Warranty, Service, and Technical SupportOnline Warranty Registration Repair Procedures for International DistributorsReplacement Parts Technical SupportInternet Sites Country TelephoneAppendixes Upgrade Overview Appendix a Upgrading Your Modem’s FirmwareDownload the Upgrade File Upgrade the Modem’s Firmware Modem Does Not Respond to Commands Appendix B TroubleshootingNone of the LEDs Light When the Modem Is On Appendix B Troubleshooting Modem Dials But Cannot Make a Connection Modem Cannot Connect When Answering Modem Disconnects While On-lineFile Transfer Is Slower Than It Should Be Am Losing DataAm Getting Garbage Characters on the Monitor Command Values Description Apendix C AT Command SummaryAppendix C AT Command Summary MultiModemBA User Guide Command Values Description SN d$Fn RF n $SBn Break Atcr Callback Security/Remote Configuration Command Summary #Syyyyyyyyyy Password Command SummaryCommand Description #Ixxxxxxxxxx 25bis Commands 25bis Operation Delayed and Forbidden NumbersAppendix D V.25bis Operation 25bis Mode AT Commands 25bis DIP-Switches25bis Set-Up and Initialization Appendix D V.25bis Operation25bis AT Commands Enable/Disable V.25bis Mode $V CommandChange Serial Baud Rate CSP Command 25bis Responses Result CodesDial Phone Number Provided CRN Command Listing Delayed Phone Numbers RLD CommandListing Forbidden Phone Number RLF Command Disregard or Connect to Incoming Calls DIC or CIC CommandDTR Dialing $D Command ITU V.25bis Country Specific InformationItaly SwitzerlandAppendix E MultiModemBA Cables Austria FranceBelgium SingaporeAppendix E MultiModemBA Cables Figure E-1. RS232 Cable IBM PCAppendix F Regulatory Information FCC Part FCC Part 68 TelecomAppendix F Regulatory Information Industry CanadaCanadian Limitations Notice 104105 EMC, Safety, and R&TTE Directive ComplianceInternational Modem Restrictions Index 106Index 107PBX/CBX Disconnect Drop Time for DSR/CTS/CD53 108109
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