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AT Commands


The following lists the AT control commands that a device is expected to support. However, a device may support more commands than listed. For example, some modems support both AT+CGMI and AT+GMI to retrieve the manufacturer name, while only AT+CGMI is required.

In the future, additional commands from the GSM specifications 3GPP TS 27.005 and 3GPP TS 27.007 may be required, so it is recommended that all device manufacturers fully comply with these 3GPP specifications.

General commands (3GPP TS 27.007, section 5)

AT+CGMIRequest manufacturer information
AT+CGMMRequest model identification
AT+CGMRRequest revision identification
AT+CGSNRequest product serial number identification (of the device, not SIM card)
AT+CSCSSelect TE character set
AT+CIMIRequest international mobile subscriber identity
AT+CMUXMultiplexing mode

Call control commands (3GPP TS 27.007, section 6)

ATDnnn;Dial "nnn" in voice mode
ATDnnnDial "nnn" in data mode
ATHHangup the current call
ATAAnswer an incoming call
AT+CBSTSelect bearer service type
AT+CRCCellular result codes
RING, +CRINGUnsolicited result codes for incoming ring notifications
NO CARRIER, NO ANSWER, NO DIALTONE, BUSYUnsolicited result codes that indicate call termination

Note: When the ATD command is used with a trailing ';', it is highly recommended that it immediately return to command mode after command processing. Some modems have been known to wait until the receiving party answers the call, or busy is detected, before returning to command mode. Such modems are not compliant with the 3GPP specification but can still be supported by overriding QModemCallProvider::atdBehavior() in the modem vendor plug-in.

The 3GPP TS specification permits ATD to be used in a special mode for dialing directly from phone books. This mode is not required as Qt Extended implements its own algorithm for converting phone book entries to numbers.

It is important that ATD recognize numbers starting with + as international, and all other numbers as being local.

Network service related commands (3GPP TS 27.007, section 7)

AT+CNUMSubscriber number
AT+CREGNetwork registration
+CREGUnsolicited result code for network registration events
AT+COPSOperator (PLMN) selection
AT+CLCKFacility lock
AT+CPWDChange password
AT+CLIPCalling line identification presentation
+CLIPUnsolicited result code for caller identification presentation
AT+CLIRCalling line identification restriction
AT+COLPConnected line identification presentation
+COLPUnsolicited result code for connected line identification presentation
AT+CCFCCall forwarding number and conditions
AT+CCWACall waiting
+CCWAUnsolicited result code for call waiting
AT+CHLDCall related supplementary services
AT+CTFRCall deflection
AT+CUSDUnstructured supplementary service data
+CUSBUnsolicited result code for unstructured supplementary service events
AT+CAOCAdvice of charge
+CCCMUnsolicited result code for advice of charge indications
AT+CSSNSupplementary service notifications
+CSSIUnsolicited result code for mobile-originated call setup supplementary services
+CSSUUnsolicited result code for mobile-terminated call setup supplementary services
AT+CLCCList current calls
AT+CPOLPreferred PLMN list
AT+CPLSSelection of preferred PLMN list
AT+COPNRead operator names

Mobile termination control and status commands (3GPP TS 27.007, section 8)

AT+CFUNSet phone functionality
AT+CBCBattery charge
+CBCUnsolicited result code for battery charge notifications
AT+CSQSignal quality
+CSQUnsolicited result code for signal quality notifications
AT+CINDIndicator control
+CIEVUnsolicited result code for indicator control events
AT+CMERMobile termination event reporting
AT+CPBSSelect phone book memory storage
AT+CPBRRead phone book entries
AT+CPBWWrite phone book entry
AT+CSIMGeneric SIM access
AT+CRSMRestricted SIM access
AT+CVIBVibrator mode
AT+CACMAccumulated call meter
AT+CAMMAccumulated call meter maximum
AT+CPUCPrice per unit and currency table
AT+CCWECall meter maximum event
+CCWVUnsolicited result code for call meter maximum events
AT+CSVMSet voice mail number
AT+CTZRTime zone reporting
+CTZVUnsolicited result code for time zone change events

The phone book commands are intended for accessing phone books stored on SIM cards, typically the SM phone book. Qt Extended provides its own mechanisms for managing phone books stored within the phone memory.

Mobile termination errors (3GPP TS 27.007, section 9)

AT+CMEEReport mobile termination error

Commands for packet domain, GPRS (3GPP TS 27.007, section 10)

AT+CGDCONTDefine PDP context
AT+CGATTPS attach or detach
AT+CGREGGPRS network registration status
+CGREGUnsolicited result code for GPRS network registration status
AT+CGSMSSelect service for MO SMS messages
ATD*99*...Request packet domain service

SMS commands (3GPP TS 27.005)

AT+CPMSPreferred message storage
AT+CMGFMessage format (we use format 0: PDU)
AT+CSCAService centre address
AT+CSCBSelect cell broadcast message types
AT+CNMINew message indications to TE
AT+CMGLList messages
AT+CMGRRead message
AT+CMGSSend message
AT+CMGDDelete message
AT+CMMSMore messages to send
+CMTINotification of SMS message delivery
+CMTNotification of a directly delievered SMS message
+CDSINotification of an SMS status report message
+CBMNotification of a directly delivered cell broadcast message

It is assumed that incoming SMS messages are stored in a temporary storage area on the device and that Qt Extended will retrieve the messages using the AT+CMGL and AT+CMGR commands.

Multiplexing commands (3GPP TS 07.10)

Qt Extended expects to use 3GPP TS 07.10 multiplexing to establish multiple communications paths with the modem. The modem needs to support the AT+CMUX command plus the basic packet mode in 3GPP TS 07.10. If the modem supports some other form of multiplexing, then it is necessary to implement a multiplexer plug-in.

Other commands (3GPP TS 27.007, Appendix C)

AT+FCLASSSelect mode
AT+VGRReceive gain selection
AT+VGTTransmit gain selection
AT+VTSDTMF and tone generation

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Qt Extended 4.4.3