$SB300, $SB1200, $SB2400, $SB4800 | Multi-Tech Systems MT2834MR6

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. 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 MT2834MR6 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.
	$SB300	300 bps	$SB1200	1200 bps
	$SB2400	2400 bps	$SB4800	4800 bps
	$SB9600	9600 bps	$SB19200	19,200 bps
	$SB38400	38,400 bps	$SB57600	57,600 bps
	$SB115200	115,200 bps ( default)

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Multi-Tech Systems MT2834MR6 manual $SBn Serial Port Baud Rate = speed Default $SB57600, $SB300, $SB1200, $SB2400, $SB4800

Contents

User Guide Revision Date Description Trademarks Contents Registers Warranty & Service Index 116 Introduction Introduction Manual Organization Description FCC Fax Update FCC Regulations for Telephone Line Interconnection Canadian Limitations Notice Technical Specifications 300 bps DiagnosticsBell 103/113 Fax Carrier Power Supply Speed Modem LED IndicatorsBusy Switch Data Rate bps LED State 10 MT2834MR6 Installation Notes Safety Warnings Dialing and Answering Dial-Up Automatic Answering Dial-Up Handshaking Details Call Termination AT Commands Working with AT Commands Modes of Operation Command Structure Command Editing AT Commands Modem baud rate Baud adjustFlow control disabled Serial port baud rate Escape sequence selection Force answer modeAlternate out-of-band escape sequence Go back online Dial Dialing CommandsDefault none = phone number Default R0 Dial Modifier CommandsDefault P Pulse or Tone Dialing Or 4 through 255 seconds International models ATDT1028806127853500 $123456789 Phone Number Memory Commands NdNe Number Linking = 0 or = 1 or Default none T14082345678 P9,T14089876543 Default &F8 Configuration Storage and Recall CommandsDefault &W1 = 0, 8, or AT&F8&W0 AT&W1 defaultATZ AT&F9&W0 Modem Response Result Code Commands Default &A0 DefaultResult Codes and Call Progress Selection Default B0 Online Connection Commands#An Auto Speed Detection Default #A0 DCn AT Command Control = 0 or Default %DC0 DTn Dtmf Detection = 0 or Default DT0 CDn Cleardown at Disconnect = 0 or Default &CD0#Fn Fallback Modes = 0, 1, or Default #F2 Default &P0 Models outside U.K Default &G0 models outside U.KDefault *H0 G2 U.K. models only Default Y0 #T0 disables TCM#T1 enables TCM Issued V.34 Commands Default &D2 RS-232 Interface CommandsDefault &C1 Default &R1 S0 forces DSR high Default &S1Go high again S1 allows DSR to act normally, that is, to follow CD Default &E15 Error Correction and Data Compression CommandsDefault &E1 #Ln Error Correction Modes Default #L0 $An Autoreliable Buffering = 0 or Default $A0 $En Error Correction at 300 bps = 0 or Default $E0$Rn Retransmit Count = 0 or Default $R0 Speed Conversion Commands $SB1200 $SBn Serial Port Baud Rate = speed Default $SB57600$SB300 $SB2400 Immediate Action Commands Rate Renegotiation $EBn Asynchronous Word Length = 0 or Default $EB0 Flow Control CommandsBSn Maximum Reliable Block Size = 0 or Default &BS1 Flow Control Disable Non-Error Correction Mode Flow Control Default &E6Default &E8 Default &E10 Pacing Computer-Initiated Flow Control Default &E13#Xn Number of Xoff Characters Sent = 0 or Default #X0 = 12 or Escape Sequences Remote Configuration Commands Atcr Remote Configuration Escape Sequence Line Probe Commands Diagnostic Commands Registers Registers Default 8 H Default 13 MDefault 10 J Return Character Unit 1 second Time for Carrier Abort TimerDefault 45 North America and International Range 1-255 U.S.A Maximum S11 value is 255 ms 255 units Registers Registers Examples of Assigning Values Reading and Assigning S-Register ValuesExamples of Reading Values AT Commands Affecting S-Registers Error Correction, Data Compression & Speed Conversion Error Correction, Data Compression, and Speed Conversion How V.42 Detects and Corrects Errors Data Compression MNP Classes 2 #L1 Command V.42 Mode Select Command #L1 #L0 Command 3 #L2 Command Autoreliable Mode &E1 Non-Error Correction Mode &E0Reliable Mode &E2 Modes of Operation Flow Control Flow control and pacing 1 XON/XOFF Flow Control &E5 Modem-Initiated Flow ControlHardware Flow Control &E4 1 XON/XOFF Pass-Through &E7 Non-Error Correction Mode Flow Control &E10 and &E11Pacing &E13 Hewlett Packard ENQ/ACK Pacing &E9 Modem-Initiated Flow Control 10.1 V.42 Error Correction ModesNon-Error Correction Mode Flow Control 10.3 XON/XOFF Pass-Through Result Codes MNP Error CorrectionLAP-M Error Correction Speed Conversion Baud Adjust $BA Modem Baud Rate $MB Serial Port Baud Rate $SB Maximum Block Size &BS Related CommandsAutoreliable Buffering $A Autoreliable Fallback Character $F Summary 13.5 V.42 Error Correction at 300 bps $ERetransmit Count $R Testing & Troubleshooting Testing and Troubleshooting Test Procedure Local Analog Loopback Test V.54 Loop Remote Digital Loopback Test V.54 Loop Remote digital loopback test Local Digital Loopback Test V.54 Loop Local digital loopback test Warranty & Service Warranty Multi-Tech Systems, Inc. Warranty & Repairs Policies2 U.S. and Canadian Customers International Customers outside U.S.A. and Canada International Distributors Repair Procedures for International Customers Repair Procedures for U.S. and Canadian CustomersRepairs Internet Site Technical SupportCountry Telephone Appendices Ascii Conversion Chart Appendix a Appendix B Dial Pulses Tone Dial Frequencies Figure B-2. Standard Dtmf frequencies Appendix C Result Code Summary Standard AT Result Codes &Q1 Appendix D Register Unit Range Default DescriptionRegister Summary S34 Command Values Description AT Command SummaryAppendix E CDn 100 101 102 103 104 105 Signal Information Negative Positive RS-232C Interface SpecificationsAppendix F Functional Description of the RS-232C Signals Transmitted Data TD Pin 2 To modem Test Voltage +V Pin From modem External Transmit Clock XTC Pin To modem Cable and Connector Diagrams Appendix G Appendix H Introduction to MultiTech Escape Methods How to Select an Escape Method Escape Method 1 +++ATCR Registers and Escape Sequence Aborting an Escape Sequence Basic Procedure Introduction to Remote ConfigurationSetup Changing the Passwords Changing the Remote Escape Character Index Index 118 119 120 121 122 S000326A