Multi-Tech Systems MT3334HD8 manual $MBn Modem Baud Rate, $SBn Serial Port Baud Rate

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MT3334HD8 User Guide

$MBn Modem Baud Rate

n = speed in bits per second Default: $MB33600

The $MB command sets a modem’s initial transmission speed for originate mode. In V.32 mode (9600 bps), it also sets the transmission speed for answer mode. With speed conversion on, this transmission speed can be different from the serial port speed.

When the modem answers a call from another modem, it automatically switches its transmission speed to match the calling modem. However, if the MT3334HD8 originates a call to another modem that is unable to connect at the transmission speed of the MT3334HD8, the MT3334HD8 will automatically drop to a lower speed in an attempt to match the speed of the other modem.

For example, if the MT3334HD8 is set for 14,400 bps and calls another modem that has a top speed of 2400 bps, it will drop to 2400 bps.

$MB75

ITU-T V.23 mode

$MB300

300 bps

$MB1200

1200 bps

$MB2400

2400 bps

$MB4800

4800 bps

$MB7200

7200 bps

$MB9600

9600 bps

$MB12000

12,000 bps

$MB14400

14,400 bps

$MB16800

16,800 bps

$MB19200

19,200 bps

$MB28800

28,800 bps

$MB33600

33,600 bps (factory default)

Speed conversion must be on for this command to work. If baud adjust is on ($BA1), speed conversion is off and a modem baud rate command will be ignored.

The S48 register also can affect maximum transmission speed. See Chapter 4.

$SBn Serial Port Baud Rate

n = speed

Default: $SB57600

The $SB command sets the speed of the MT3334HD8’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. When baud adjust is on, as soon as the modem receives its first AT command, it automatically adjusts its serial port baud rate to match the speed of the computer or terminal to which it is connected. However, in applications such as automatic answer, the modem may not receive AT commands. In this case it is helpful to be able to preset the serial port baud rate with the $SB command.

In addition to setting the modem’s serial port speed, this command sets the speed at which the modem issues command mode responses (result codes).

The MT3334HD8 accepts AT commands at any speed, regardless of the speed preset by the $SB command. If the modem receives a command at a speed different from the preset speed, the modem switches its serial port baud rate to match the new command speed, even though the baud rate value stored by the $SB command remains the same. This provides you with a convenient way to switch the serial port speed while still making it easy to automatically return to the original speed the next time the modem is powered up or reset.

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CommPlete Communications Server

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Contents MT3334HD8 Modem User Guide Multi-Tech Systems, Inc Woodale Drive Mounds View, Minnesota CommPlete Communications Server FCC Fax Warning Canadian Limitations NoticeTable of Contents Testing the MT3334HD8 Warranty, Service, and Technical SupportAppendix D Appendix FIntroduction LED Indicators Power SuppliesIntroduction Manual OrganizationInstallation Technical Specifications Data Rates ModemIntroduction 2400 & 1200 bps MT3334HD8 User Guide Power Installation Safety Warnings MT3334HD8 modem cardPre-Installation Notes Installation ProcedurePage AT Commands Command Structure Working with AT CommandsModes of Operation Command Editing AT Commands by Function $BA Dialing Commands Dial Modifier CommandsDs Dial Continuous RedialPulse or Tone Dialing Wait for New Dial ToneRn Reverse Originate/Answer Mode Return to Command Mode After DialingDialing Pause Flash On-HookPhone Number Memory Commands @ Quiet AnswerCall Card Tone Detect DsNd Store a Phone NumberConfiguration Storage and Recall Commands Wn Store ConfigurationNdNe Number Linking List Stored Telephone NumbersFn Load Default Configuration Modem Response Result Code CommandsReset Modem Echo Command Mode Characters Result Codes Verbose/Terse Online Connection Commands An Answerback#An Auto Speed Detection Bn Answer ToneCDn Cleardown at Disconnect DCn AT Command ControlDTn Dtmf Detection #Fn Fallback Modes Gn Guard TonesHn Busy-Out After Disconnect Pn Set Pulse-Dial Ratios$Tn Calling Tone RDn Square Wave Ring Detect#Tn Trellis-Coded Modulation Commands Fn Echo Canceler Frequency Offset CompensationYn Long Space Disconnect RAn Asymmetric Bit RateCn Carrier Detect Control RS-232 Interface CommandsDn Data Terminal Ready Control Rn Clear to Send Control Sn Data Set Ready ControlRFn CTS/RTS Interaction Control SFn DSR/CD Interaction ControlError Correction and Data Compression Commands En Error Correction Modes#Ln V.42 Error Correction Modes En Data Compression$Fn Auto-Reliable Fallback Character Enable/Disable $En V.42 Error Correction at 300 bps$An Auto-Reliable Buffering $BAn Baud Adjust Speed Conversion Commands$Rn Retransmit Count $MBn Modem Baud Rate $SBn Serial Port Baud RateImmediate Action Commands Repeat Last CommandInquire Product Code L5, L7 List Current Operating ParametersFlow Control Commands E3 Flow Control Disable En Non-Error Correction Mode Flow ControlE4 Hardware Flow Control E5 XON/XOFF Flow ControlEn Pacing Computer-Initiated Flow Control #Xn Number of Xoff Characters SentForce Answer Mode Escape Sequences+++ATCR In-Band Escape Sequence Breakatcr Out-of-Band Escape SequenceRemote Configuration Commands Atcr Remote Configuration Escape Sequence#Ixxxxxx Change Login Password Go Back OnlineLine Probe Commands #Syyyyyy Change Setup PasswordDPn Read Line Probe Data DFn Format Line Probe DataDiagnostic Commands Tn Respond to Remote Digital Loopback SignalRP Immediate Line Probe Ln Display Line Probe DataUn Loopback Test Modes MT3334HD8 User Guide Registers Registers S0 Number of Rings Until Modem AnswersS1 Ring Count S2 Escape Code CharacterS7 Time for Carrier Abort Timer S4 Line Feed CharacterS5 Backspace Character S6 Wait Time for Dial ToneS10 Carrier Loss Disconnect Delay Time S13 Remote Configuration Escape CharacterS9 Carrier Detect Response Time S11 Tone Dialing Spacing and DurationS30 Inactivity Timer S34 Command Buffer Length After Online Escape SequenceS24 PBX/CBX Disconnect Drop Time for DSR/CTS/CD S25 DTR Dropout TimeS94 Out-of-Service Time S37 DTR Busy-In TimeS43 Force V.34 Connect Speed S48 Maximum V.34 Connect SpeedAT Commands that Affect S-Registers Reading and Assigning S-Register ValuesExamples of Assigning Values Examples of Reading ValuesAT&E2$SP1#L3$R0$MB19200$SB115200$EB1S0=10&W0CR Testing the MT3334HD8 Test procedure Local Analog Loopback Test V.54 LoopTesting the MT3334HD8 Remote Digital Loopback Test V.54 LoopDial the remote modem and establish your online connection Local Digital Loopback Test V.54 Loop Local digital loopback testPage Warranty, Service, and Technical Support Limited Warranty ServiceTechnical Support Recording Product InformationLogging onto the Multi-Tech BBS Multi-Tech BBSDownloading a File About CompuServe Reading a MessageLeaving a Message BulletinsAbout the Multi-Tech Fax-Back Service About the InternetUsing FlashPro to Upgrade Firmware Upgrading the MT3334HD8 FirmwareMT3334HD8 User Guide Appendixes Appendix a Ascii Conversion Chart Ctrl Code HEX DECDial Pulses Appendix B Dial Pulses and TonesTone Dial Frequencies Figure B-2. Standard Dtmf frequencies Appendix C Result Code Summary Multi-Tech Result Codes &Q0Standard AT Result Codes &Q1 Register Unit Range Default Description Appendix D S-Register SummarySets fixed V.34 connect speed = 28800 bps Appendix E AT Command Summary ReturnCDn AT Command Summary $Fn Command Values Description Command Values Description $MBn RAn Command Values Description SFn Command Values Description #Vn Breakatcr Basic Procedure Appendix F Remote ConfigurationSetup Changing the Passwords Changing the Remote Escape CharacterIndex MT3334HD8 User Guide Index Long space break Pacing, 36, 37, 38 enable/disable, 38 ENQ/ACK Commands Loopback tests, 42, 43, 54, 56 tone detection
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