Multi-Tech Systems MT3334SMI manual Answer, Repeat Last Command

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ModemModule Developer’s Guide

Introduction

The AT commands are used to control the operation of your modem. They are called AT commands because each command must be preceded by the characters AT to get the ATtention of the modem.

AT commands can be issued only when the modem is in command mode or online command mode. The modem is in command mode whenever it is not connected to another modem. The modem is in data mode whenever it is connected to another modem and ready to exchange data. Online command mode is a temporary state in which you can issue commands to the modem while connected to another modem. To put the modem into online command mode from data mode, you must issue an escape sequence (+++) followed immediately by the AT characters and the command, e.g., +++ATH to hang up the modem. To return to data mode from online command mode, you must issue the command ATO.

To send AT commands to the modem you must use a communications program, such as the HyperTerminal applet in Windows 98/95 and NT 4.0, or some other available terminal program. You can issue commands to the modem either directly, by typing them in the terminal window of the communications program, or indirectly, by configuring the operating system or communications program to send the commands automatically. Fortunately, communications programs make daily operation of modems effortless by hiding the commands from the user. Most users, therefore, need to use AT commands only when reconfiguring the modem, e.g., to turn autoanswer on or off.

The format for entering an AT command is ATXn, where X is the command and n is the specific value for the command, sometimes called the command parameter. The value is always a number. If the value is zero, you can omit it from the command; thus, AT&W is equivalent to AT&W0. Most commands have a default value, which is the value that is set at the factory. The default values are shown in the “AT Command Summary” (See below).

You must press ENTER (depending on the terminal program it could be some other key) to send the command to the modem. Any time the modem receives a command, it sends a response known as a result code. The most common result codes are OK, ERROR, and the CONNECT messages that the modem sends to the computer when it is connecting to another modem. For a table of valid result codes, see “Result Codes” at the end of this chapter.

You can issue several commands in one line, in what is called a command string. The command string begins with AT and ends when you press ENTER. Spaces to separate the commands are optional; they are ignored by the command interpreter. The most familiar command string is the initialization string, which is used to configure the modem when it is turned on or reset, or when your communications software calls another modem.

AT Command Summary

Command: AT

Attention Code

Values:

n/a

Description:

The attention code precedes all command lines except A/, A:, and escape

 

sequences.

Command:

ENTER Key

Values:

n/a

Description:

Press the ENTER (RETURN) key to execute most commands.

Command: A

Answer

Values:

n/a

Description:

Answer call before final ring.

Command: A/

Repeat Last Command

Values:

n/a

Description:

Repeat the last command string. Do not precede this command with AT. Do not

 

press ENTER to execute.

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MT3334SMI

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Contents Model MT3334SMI Evaluation Kit Data/Fax Socketed ModemRevision Description PatentsContents Index Introduction and Description Features IntroductionProduct Description ModemModule Developer’s GuideTechnical Specifications Introduction and Description1200 bps Physical Dimensions MT3334SMI Physical DimensionsLED1-LED4 Test/Demo Board SpecificationsDS1 Test/Demo Board Block Diagram MT3334SMI Test/Demo Board Block DiagramMT3334SMI Pin-out MT3334SMI PinoutTypical Application MT3334SMI Design Considerations Hardware ConsiderationsRecommended Transceiver PC Board Layout ConsiderationsCalculating Z for Tip and Ring Traces Qty Name Description MT3334SMI PlacementKey Telecom Labeling Requirements FCC PartMultiple Listing ReregistrationIndustry Canada CS-03 AT Commands, S-Registers, and Result Codes Repeat Last Command AnswerAT Commands, S-Registers, and Result Codes Monitor Speaker Volume Monitor Speaker ModeReturn Online to Data Mode Result Codes Enable/DisableModem Reset Sr? Read Register ValueTone Dialing Result Code FormatCommand &Fn Load Factory Settings Asynchronous Communications ModeDisplay Current Settings Store Current ConfigurationCommand &Zy=x Store Dialing Command \An Select Maximum MNP Block Size\Bn Transmit Break \Jn Data Buffer Control\Nn Error Correction Mode Selection \Tn Inactivity Timer\Qn Flow Control Selection \Vn Protocol Result CodeCommand %DCn AT Command Control Command %En Fallback and Fall Forward ControlCommand +ES=n Enable Synchronous Buffered Mode Enter Setup PasswordRegister Unit Range Default Description RegistersS43 Result Codes Terse Verbose DescriptionClass 1 Fax Commands Class 1 Fax Command Summary Command DescriptionClass 1 Fax Commands Fax MOD Modulation Parameter Values CommandFunction Display Current Class Values Default Data modem Result Code MeaningFunction ModemModule Developer’s Guide CommandFunction Select Service Class Values Default Data mode Class 1 Fax Commands +FRS=? Enter+FRM=? Enter Sample Sessions Flow ControlResult Codes Action by Command Respone Local Modem Remote PC AT+FRH=3 No Carrier ModemModule Developer’s Guide Class 2 Fax Commands Class 2 Fax Command Implementation Class 2 Fax Commands EIA SP-2388 August+FAA +FAXERR+FCR +FBOR+FCQ +FDCC Fax Capability Parameters+FDCS Current Session Results+FDFFC Data Compression Format Conversion+FDIS Current Session Parameters+FDR +FDT+FECM +FET+FK +FLID+FLNFC +FLPL+FPTS +FRBC+FREL +FSPL+FHNG +FTSIMT3334SMI Remote Configuration Basic Procedure SetupChanging the Setup Password ModemModule User GuideRemote Configuration Changing the Remote Escape CharacterMT3334SMI Troubleshooting Test procedure Local Analog Loopback Test V.54 LoopTroubleshooting Remote Digital Loopback Test V.54 LoopLocal Digital Loopback Test V.54 Loop Local digital loopback testUpgrade Procedure Upgrade Overview Identify the Modem FirmwareIdentify the Current Firmware Version Multi-Tech Web SiteMulti-Tech BBS Download the Upgrade FileUpgrade Procedure Extract the Upgrade Files Use FlashPro to Upgrade Modem FirmwareRestore Your Parameters Clear Your Stored ParamentersAppendixes MT3334SMI FCC FAX Update International Modem RestrictionsCanadian Limitations Notice AppendixesNew Zealand Telecom Warning Notice EMC, Safety and Terminal Directive ComplianceEuropean Directives User Guide Statement Appendix B Multi-Tech Flash Programming Protocol IntroductionProgramming the Modem Handshake SequenceModemModule Developer’s Guide Program Sequence Other supported boot code commandsOther programming concerns Xxxx Intel Hex FormatData Record Eeee Extended Address RecordEnd of File Record Index IndexMT3334SM MT3334SMI MT3334SM
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