AT&M Synchronous/Asynchronous Mode, AT&M1, AT&M2 | Telenetics 56

ATCommands

AT&M Synchronous/Asynchronous Mode

The &M command enables you to select either asynchronous or synchronous operation.

During asynchronous transmissions, the time between characters being sent may vary, and the characters are delimited by start and stop bits to co-ordinate data transfer.

During synchronous transmissions, the interval between the transmission of each character is of equal length, controlled by clock signals.

Synchronous transmission is most commonly used in communications involving mainframe computers.

Options

AT&M0 ■	Asynchronous mode
	The modem will dial and answer in the asynchronous mode and then enter
	asynchronous on-line state when a connection is established.
AT&M1	Synchronous mode with asynchronous dialling The modem remains in
	asynchronous mode while it is on-hook, dialling or answering. When a
	connection is established, the modem automatically switches to synchronous
	operation.
AT&M2	Synchronous mode with dialling invoked by the DTR signal
	The modem remains in asynchronous mode while it is on-hook, dialling or
	answering.
	You must issue the AT&D2 command prior to using this synchronous mode.
	When your local computer asserts the DTR (Data Terminal Ready) signal,
	the modem will dial stored phone number zero (see the &Zn command).
	When an incoming call is detected, the modem will attempt to answer it as
	soon as the DTR signal is asserted and the number of rings specified in S
	Register 0 is reached.
	As soon as a connection is established, the modem automatically switches to
	synchronous operation.
	If DTR is lowered at any time, the modem will hang up.
AT&M4	Asynchronous mode with dialling invoked by the DTR signal
	When your computer asserts the DTR signal, the modem will dial stored
	phone number zero (see &Zn command).
	You must issue the AT&D2 command prior to using this synchronous mode.
	When an incoming call is detected, the modem will attempt to answer it as
	soon as the DTR signal is asserted and the number of rings specified in S
	Register 0 is reached.
	If DTR is lowered at any time, the modem will hang up.

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Telenetics 56 manual AT&M Synchronous/Asynchronous Mode, AT&M1, AT&M2, AT&M4

Contents

Global Carrier 56 Modem User’s Guide Page Mailing List Contact InformationTechnical Support Contents 106 203 248 RS-232 Signals Error CorrectionDumb Mode AT Commands Additional Items You Need Unpacking Your Hardware DTE RS232 Hardware OverviewBack View Front View Finding a Suitable Location Installation Summary Telco/Dial Line Telephone Connecting the CablesSet Connector Power Input Windows ME Driver InstallationWindows Modem LED Display Three Four Front Panel Mode LEDsLine Modulation One Escape Sequence AT CommandsMultiple Commands Help Command Repeat Command Dialling Response Codes Dial Modifiers Answering Calls Hanging UpStored Number Dialling ATCommands Terminal Speeds Selecting Speeds Line Speeds Setting Terminal Speeds90 & V.34 Typical Settings Example 2 Dialling other modems at 14,400 bps or V.32bis 32bis Modem Typical SettingsExample 3 Dialling information services at 1200 bps or Example 2 Dialling other modems at 19,200 bps V.34 or V.FC Example 3 Answering incoming calls Transparent XON/XOFF Flow Control Flow ControlRTS/CTS Flow Control XON/XOFF Flow Control AT\T5 Inactivity TimerCommand Timer Failsafe Flow Control Viewing the Current Configuration Configuring the Modem Error Correction Protocols Error Correction Data Compression Reliable ModeAuto-Reliable Mode Improving Performance with MNP Cellular Modem Users Speed Changes ATCommands Security Menu Entering a Security Password Adding and Changing Users Listing Existing Users Access RecordRemoving Users Quitting the Menu Enabling Modem Security Callback Security Downloading the Security File Integrating Caller ID into the Security Database Encryption DES Multikey SuperSecure Advanced Security Mode Entering a Key for Each User Ringing Accessing a System Using SuperSecure Enabling Rotating Secondary Keys Password Expiry Option Minimum Password Length Entering a Password in the Remote Modem’s DatabaseEntering a New Password in the Local Modem’s Database Security Database Lock Option Outdial Disable Option General Notes on Data Security Dial Stored Phone Numbers Only Option Synchronous Operation Synchronous Modes Dialling Synchronous ModeSelecting Synchronous Mode Answering Calls Hanging Up Dialling Leased Line Operations Smart Leased- Line ModeCalling and AnsweringUsing &L1 Auto Leased Line Operation &L2 or &L3 Wire Leased Line setup via audio port Selecting Communications Speeds Setting Up your Modem Hints for Unix Computers and Multiplexers Dialling in Dumb Mode Using the Talk /Data Button to Dial Using DTR to Dial Answering Calls in Dumb Mode Manual Answering AT%F Option SwitchesSwitch Description Selecting V.25bis Operation 25bis Operations Data Formats Overridden Settings25bis Commands Verbal Meaning 25bis Indications Hanging Up Direct Dialling Selecting Speeds Asynchronous Notes DB25 Pin SignalModem Cable Synchronous Character Encoding Hdlc Notes AT-SDR=7 Distinctive Ring CommandsAT-SDR=0 Enabling the Caller ID Function Caller ID AT#CID=? Integrating Caller ID into the Security DatabaseAT#CID? Distinctive Ringing ‘Tune’ Option Call Log Format Call Logging See Also +++ Escape SequenceOptions ATA, ATD, ATH, ATZ, AT&T Remote Access Sequence Request remote access AT?&T AT? Interactive Command HelpAT? Repeat Last Command ATA Answer ATBn Select Communications Standard Command Speed B10 32 at 4800bps B11 32 at 7200bps B12 See Also Example ATD Dial Pause Dial Modifiers @ wait for quiet answer Return to local command stateReverse mode Last number redial Or disable calling tonesInitiate MNP 10 at 1200 bps MNP 10 Cellular Option Wait for dial tone Hook flash=n dial stored phone number n See Also ATE0 ATE EchoRange ATH2 ATH Hang UpATH0 ATH1 ATI Identity ATL1 ATL Speaker Volume ControlRange See Also ATL0 ATM3 ATM MonitorATM0 ATM2 ATO Return to On-line State ATO30 ATO27ATO28 ATO29 ATQ2 ATQ Quiet Suppress Response CodesATQ1 ATR Set Terminal Speed ATR57 ATR26ATR28 ATR38 ATSn? Display S Register Value ATSn= Set S Register Value Verbal Numeric Meaning ATV Verbal Response Codes ATW1 ATW Connection Speed InformationATW0 ATX Extended Response Codes Command ATZ2 ATZn Restore Configuration ProfileATZ0 ATZ1 Range Options AT&B Character Length AT&C3 AT&C Controlling Data Carrier DetectAT&C0 AT&C2 AT&D3 AT&D Controlling Data Terminal ReadyAT&D0 AT&D1 AT&F. Reinitialise Modem AT&F2 AT&F Restore Factory DefaultsAT&F0 AT&F1 AT&G2 AT&G Guard ToneAT&G1 AT&H1 AT&H Clock Control AT&K5 AT&K Flow ControlAT&K0 AT&K4 Modem to the computer AT&L Leased Line AT&M4 AT&M Synchronous/Asynchronous ModeAT&M1 AT&M2 Range See Also AT&N0 AT&N Abort Connection AT&R1 AT&R RTS/CTS Control AT&S2 AT&S Controlling DSRAT&S1 AT&Vn View Active Configuration Profile AT&W2 AT&Wn Write Configuration ParametersAT&W0 AT&W1 AT&X2 AT&X Transmit ClockAT&X1 AT&Y2 AT&Yn Select Stored Profile on Power UpAT&Y0 AT&Y1 AT&Z Stored Phone Number AT#A1 AT#A Universal Remote AccessAT#A0 Range AT#B1 AT#B 1200bps Originate Mode AT#C0 AT#C V.25 Calling Tones AT#CID Caller ID AT#CID3 AT#CID0AT#CID1 AT#CID2 AT#D1 AT#D V.25bis Direct Calling AT#E3 AT#E EncryptionAT#E1 AT#E2 AT#H Display Help AT#I1 AT#I V.22bis Leased Line AT#J0 AT#J V.42 Capability Checking AT#K2 AT#K MNP 10 modeAT#K0 AT#M3 AT#M Command Mode SelectionAT#M1 AT#M2 AT#N1 AT#N V.25bis Character Encoding AT#O3 AT#O Buffer OverflowAT#O1 AT#O2 AT#Q V.25bis Terminal Speed AT#R Enable Remote Control AT#S Security Menu AT#U1 AT#U V.25bis Character Set AT#V0 AT#V Verifier AT%B2 AT%B AutoAnswer Setting Examples AT%C Compression Control AT%D Set Disconnect Delay AT%E1 AT%E Auto EQM RetrainAT%E0 AT%F0 AT%F DTR/DSR override AT%H3 AT%H MNP 10 Negotiation SpeedAT%H1 AT%H2 AT%K1 AT%K CTS During Dial and Handshake AT%L Display Line Signal Level 11-19 AT%Ln Transmit Level Data Mode AT%M1 AT%M Mode LED Indication AT%N2 AT%N Non-Standard Terminal SpeedsAT%N1 AT%P1 AT%P Connect Message Timing AT%Q AT%Q Line Signal Quality AT%R2 AT%R CTS OverrideAT%R1 AT%S1 AT%S DSR Override AT%T1 AT%T DCD Override AT%U2 AT%U V.42 Response CodesAT%U1 AT%W1 AT%W Welcome Message AT\A2 AT\A MNP Block SizeAT\A0 AT\A1 AT\B4 Default See AlsoAT\Bn Generate Break AT\J1 AT\J Auto-Reliable Fallback AT\K Break Control Default AT\N Asynchronous Operating Mode See Also AT\Q Extended Flow Control AT\S AT\S Display Active Configuration AT\Tn Inactivity Timer Data Mode AT\V9 AT\V Error Correction Response CodesAT\V1 AT\V8 AT\X1 AT\X XON/XOFF Pass Through AT*K Select Primary DES KEY from Stored Keys Default Range See Also AT*R1 AT*R V.13 Remote RTS Signalling AT*S Change Current User Password AT*T1 AT*T Auto Call Redial AT*V1 AT*V Maximum V.42bis Dictionary Size AT*W Welcome Message Text AT*Y1 AT*Y Escape Seq. Detection in Sync AT+ICF Character Framing and Parity Select Mod AT+MS Select Modulation Automode Xlaw MinrateMaxrate Nn Automode RbsignalingConnecting with 56k technology +MS AT+MS=? Reporting Supports Options AT-Q0 AT-Q MNP10 Fallback to V.22bis AT-DATE Time & Date AT-LOG2 AT-LOG Call LogAT-LOG ATE V.32 compromise Equaliser 25BIS CIC Connect Incoming Call Modifier Meaning 25BIS CRN Dial CRS command Dial Stored Number Register 25BIS CRS Dial Stored Number 25BIS DIC Disregard Incoming Call CRS 25BIS PRN Stored Phone Number 25BIS RST Reset Reading and Changing S Registers Register Settings and Modem MemoryIntroduction Page ATS0 Rings Before Answer Default Range ATS1 Ring Count ATS2 Escape Sequence Character ATS3 Carriage Return Character Default Example ATS4 Line Feed Character ATS5 Backspace Character ATS6 Dial Tone Wait Time ATS7 Wait for Carrier ATS8 Pause Dial Modifier Delay ATS9 Carrier Detect Response Time ATS10 Lost Carrier/Hang Up Delay ATS11 Dtmf Tone Timing ATS12 Escape Sequence Guard Time ATS16 ATS16 Test in Progress read only ATS18 Test Timer ATS25 DTR Loss Detection ATS26 RTS/CTS Delay ATS27 Delay Before Dial ATS29 Hook Flash Duration Voice Mode ATS30 Inactivity TimerData Mode ATS105Voice ‘Dead-man’ Timer ATS33 EQM Threshold Value ATS38 Disconnect Delay Value Meaning ATS42 Modem Disconnect Reason ATS43 Break Sequence Length ATS45 V.22bis EQM Threshold Value ATS57 DTR High Detection ATS62 V.42 Detection Timer ATS66 Remote Access Guard Time ATS67 Remote Access Character ATS69 Command Line Time-out ATS71 Ignore Incoming Call ATS74 Disconnect Reason for Prev. Call ATS80 Flow Control High Water Mark ATS81 Flow Control Low Water Mark ATS82 Failsafe Flow Control Overrun ATS95 Extended Response Codes ATS96 Help Page Width ATS97 Help Page Length ATS30 ATS105 Voice ‘Dead Man’ Timer EQM ATS122 AutoRateChange ATS123 AutoRateChange ATS124 Duration EQM Modem Response Codes 25bis Indications Modem Response Codes Request To Send RTS Pin Signal Ground SG PinTransmit Data TxD Pin Receive Data RxD Pin Receive Clock RxC Pin Ring Indicator RI PinData Carrier Detect DCD Pin Transmit Clock TxC Pin Standard RS-232 Examples General Commands Abbreviated Command ListPage Answer mode Page #CID0 S0=0 No AutoAnswer Mod Possible Rates bps Dial Modifiers Distinctive Ring Commands AbbreviatedCommandList Page Ascii Ansi BBS BPS Clock ContentionCharacter Set Clear to Send CTS CTS CPUCRT DCE DCD DTE Mail EbcdicEeprom EIA ETX ENQ Hdlc Host Computer HeaderHertz Hz Horizontal Redundancy Checking HRC LED ISOITU Loopback Log onLog Off Longitudinal Redundancy Check Pabx NAK PEP PBX RAM Prom SIG ROMRTS Sdlc STX SOH SYN XON/XOFF ZModem Caller ID Command Sets Humidity Error CorrectionEncryption Environmental Product Warranty Return Merchandise Authorization RMA Procedure RMA Procedure Department of Canada Statement Compliances Compliances