Multi-Tech Systems MT2834MR6 5.12.3 Serial Port Baud Rate ($SB)

77

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).

For this command to work, the modem’s baud adjust feature must be turned off with the $BA command.

The MT2834MR6 will accept AT commands at any speed, regardless of the speed preset by the $SB

command. If the modem receives such a command at a speed that is different from the preset speed, the

modem switches its serial port baud rate to match the new AT command speed, although 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 using the ATZ command.

To set the serial port baud rate, type AT$SBn, where n can be 300, 1200, 2400, 4800, 9600,19,200, 38,400,

57,600, or 115,200 bps as listed below:

AT$SB300 300 bps AT$SB1200 1200 bps

AT$SB2400 2400 bps AT$SB4800 4800 bps

AT$SB9600 9600 bps AT$SB19200 19200 bps

AT$SB38400 38400 bps AT$SB57600 57,600 bps

AT$SB115200 115,200 bps (factory default)

Contents

Main Revision Date Description Contents Page Page Page Page 1.1 Introduction 1.2 Manual Organization 1.3 Description Owners Manual 1.4 FCC Regulations for Telephone Line Interconnection 1.4.1 FCC Fax Update 1.5 Canadian Limitations Notice 1.6 Technical Specifications Page 1.7 Power Supply 1.8 Modem LED Indicators Note: The MultiModemManager can perform the same function using software. 1.9 Busy Switch 1.10 MT2834MR6 Installation Notes Owners Manual Note: Such apparatus may have been approved subject to limitations in its use. 1.11 Safety Warnings Page Chapter 2 - Dialing and Answering 2.1 Introduction 2.2 Dial-Up Automatic Answering 2.3 Dial-Up Handshaking Details Chapter 2 - Dialing and Answering 2.4 Call Termination Page 3.1 Working with AT Commands 3.1.1 Modes of Operation 3.2.2 Command Structure 3.3.3 Command Editing Page Page Page 3.2 Dialing Commands 3.3 Dial Modifier Commands Page Page 3.4 Phone Number Memory Commands Page 3.5 Configuration Storage and Recall Commands Page 3.6 Modem Response (Result Code) Commands Page 3.7 Online Connection Commands Page Page Page 3.8 V.34 Commands 3.9 RS-232 Interface Commands Page 3.10 Error Correction and Data Compression Commands Page 3.11 Speed Conversion Commands Page 3.12 Immediate Action Commands Page 3.12 Flow Control Commands Page Page 3.13 Escape Sequences ATA S7 A 3.14 Remote Configuration Commands 3.15 Line Probe Commands 3.16 Diagnostic Commands Page 4.1 Introduction 4.2 S-Registers Page S7 S8 S10 S9 S9 S11 S11 S25 S24 &C Page Page 4.3 Reading and Assigning S-Register Values 4.3.1 Examples of Assigning Values 4.3.2 Examples of Reading Values 4.4 AT Commands Affecting S-Registers Page 5.1 Introduction 5.2 How V.42 Detects and Corrects Errors detected correction 5.3 Data Compression $BA0 &E5 &E4 $SB115200 #L 5.5 V.42 Mode Select Command ( #Ln #L0 #L 5.6 Modes of Operation &E0 &E1 5.6.3 Autoreliable Mode ( &E2 5.7 Flow Control 5.8 Modem-Initiated Flow Control &E5 &E4 5.8.2 Hardware Flow Control ( 5.8.1 XON/XOFF Flow Control ( &E13 5.9 Pacing ( &E9 5.9.3 Hewlett Packard ENQ/ACK Pacing ( &E11 5.10 Compression, Error Correction, Flow Control, and Pacing Commands 5.11 Result Codes 5.11.1 MNP Error Correction 5.11.2 LAP-M Error Correction 5.11.3 Data Compression 5.12 Speed Conversion $BA 5.12.1 Baud Adjust ( 5.12.2 Modem Baud Rate ($MB) 5.12.3 Serial Port Baud Rate ($SB) 5.13 Related Commands 5.13.1 Autoreliable Buffering ($A) 5.13.2 Maximum Block Size (&BS) 5.13.3 Autoreliable Fallback Character ($F) 5.13.4 Retransmit Count ($R) 5.14 Summary Page 6.1 Introduction Note: Loopback tests operate at all speeds except 300 bps. 6.2 Local Analog Loopback Test (V.54 Loop 3) 6.2.1 Test Procedure CONNECT 6.3 Remote Digital Loopback Test (V.54 Loop 2) 6.3.1 Test Procedure 6.4 Local Digital Loopback Test (V.54 Loop 2) 6.4.1 Test Procedure Page 7.1 Multi-Tech Systems, Inc. Warranty & Repairs Policies 7.1.1 Warranty mtsrepair@multitech.com www.multitech.com www.multitech.com. 7.1.3 International Customers (outside U.S.A. and Canada) 7.1.4 International Distributors 7.2 Repairs 7.2.1 Repair Procedures for U.S. and Canadian Customers 7.2.2 Repair Procedures for International Customers 7.2.3 Repair Procedures for International Distributors 7.2.4 Replacement Parts 7.3 Technical Support 7.4 Internet Site Page Appendix A ASCII Conversion Chart CTRL CODE HEX DEC CODE HEX DEC CODE HEX DEC CODE HEX DEC Appendix B Dial Pulses Tone Dial Frequencies Appendix C Result Code Summary CONNECT R or the letter &Q1 &Q Standard AT Result Codes ( L CONNECT Appendix D S-Register Summary Page Appendix E AT Command Summary Command Values Description Page &En n &E5 %Fn n $Fn n &F Page Page Page Page Page Appendix F RS-232C Interface Specifications Page Test Voltage (+V) Pin 9 (From modem) High Speed (HS) Pin 12 (From modem) Transmit Clock (TC) Pin 15 (From modem) Receive Clock (RC) Pin 17 (From modem) Data Terminal Ready (DTR) Pin 20 (To modem) Page Appendix G Cable and Connector Diagrams APPENDIX H Introduction to MultiTech Escape Methods How to Select an Escape Method Escape Method 1: +++AT<CR> Escape Method 2: <BREAK>AT<CR> S-Registers and Escape Sequence A S34 Aborting an Escape Sequence APPENDIX I Introduction to Remote Configuration Basic Procedure Setup Changing the Passwords Changing the Remote Escape Character Page Index A B C D E F G H I K L P Q R S T V W X