AT&C Controlling Data Carrier Detect, AT&C0, AT&C2 | Telenetics 56

AT&C Controlling Data Carrier Detect

The &C command enables you to control how DCD will operate. DCD is a RS-232 interface signal from the modem to a remote device, such as a terminal or a computer, indicating that the modem is receiving a carrier signal from a remote modem. This signal is switched on (asserted) when your modem is receiving a valid carrier signal from a remote modem. The &C3 option allows a connection that was commenced as a voice call to switch to fax or data mode without an interruption to the DCD signal (which might cause the application to think that the line has been lost).

☞The &C command will only have effect when the DCD option switch is in the UP position and %T0 is selected. (Refer to the Dumb Mode Section for details.)

Options

AT&C0	DCD signal is always asserted
AT&C1 ■	DCD signal responds to remote modem
AT&C2	DCD signal always on, pulses low on disconnect
AT&C3	DCD asserted during voice session

☞We recommend &C2 for UNIX computers which require DCD to be asserted when issuing commands to the modem.

Range

0-3

See Also

S Register 9	Carrier Detect Response Time
S Register 10	Lost Carrier/Hang Up Delay
%T	DCD Control
	Dumb Mode Switches
%P	Connect Message Timing

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Telenetics 56 manual AT&C Controlling Data Carrier Detect, AT&C0, AT&C2, AT&C3

Contents

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