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AT Commands

Introduction

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 phones 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 07.05 and 07.07 may be required, so it is recommended that all device manufacturers fully comply with GSM specifications.

The categories of control commands are:

• General Commands (GSM 07.07, Section 5)
• Call Control Commands (GSM 07.07, Section 6)
• Network Services Related Commands (GSM 07.07, Section 7)
• Mobile Equipment Control and Status Commands (GSM 07.07, Section 8)
• SMS Commands (GSM 07.05)
• Multiplexing Commands (GSM 07.10)
• Other Commands
• Phone-Specific Commands

General Commands (GSM 07.07, section 5)

Call Control Commands (GSM 07.07, section 6)

Note: When the ATD command is used with a trailing ';', it must return immediately to command mode after command processing. Some phones have been known to wait until the receiving party answers the call, or busy is detected, before returning to command mode. Such phones are not compliant with the GSM specification and will not be supported.

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

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

Network Services Related Commands (GSM 07.07, section 7)

Mobile Equipment Control and Status Commands (GSM 07.07, section 8)

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

SMS Commands (GSM 07.05)

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

Multiplexing Commands (GSM 07.10)

Qtopia Phone expects to use GSM 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 GSM 07.10. If the modem supports some other form of multiplexing, then it is necessary to modify muxdevice.cpp in the source code. Multiplexing support is required for GPRS.

Other Commands

Phone-specific Commands

The GSM specification lacks some functionality required to provide a complete feature set. The most important of these is Call Monitoring, that is, when an outgoing dial request is made, a method of detecting call acceptance or rejection by the other party is required.

Ericsson phones have an AT*ECAM command that is used to turn on supplementary call monitoring events. That is, each time the call status changes, the phone emits an *ECAV message with the details. It is recommended that device manufacturers provide these or similar commands.