Modem AT Commands Explained

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at command
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lte
cdma

This page provides information on modem AT commands that are commonly used and provided by leading GSM, HF, CDMA, and LTE modem manufacturers. It covers commands such as AT, AT+CFUN, ATD, ATA, ATH, AT+CGDCONT, AT+COPS, AT+CGMR, and AT+CGATT, among others.

AT commands are a popular method for configuring, monitoring, and controlling modems in various functionalities. They are applicable to diverse modems across different technologies, including HF, GSM, CDMA, and LTE. While AT commands vary from manufacturer to manufacturer due to custom designs and implementations, a basic set is derived from the Hayes standard AT commands.

The following table lists AT commands commonly used across various modem manufacturers:

AT commandDescription
ATUsed to check communication between the module and the computer.
AT+CMGF=<mode>Sets the SMS mode (PDU mode or text mode).
AT+CMGFMessage format
AT+CMGLList messages
AT+CMGRRead message
AT+CMGSSend message
AT+CMSSSend message from storage
AT+CMGWWrite message to memory
AT+CMGDDelete message
AT+CFUN=valueSets functionality to various modes such as GSM, CDMA, and LTE. Mainly used in modems supporting multi-RAT. Value ranges from 0 to 6 or more. 1 means full functionality.
ATD <number>Used to call a phone number.
ATAUsed to answer an incoming call.
ATHUsed to disconnect an established call.
AT+CGDCONT=1,"IP address","APN"Defines PDP context. APN (Access Point Name) is the gateway between the GPRS network and the internet.
AT+COPS=1,2,26201Manual PLMN (Public Land Mobile Network) selection.
AT+COPS?Provides PLMN information set in the modem.
AT+CGMRDisplays the version of the software loaded on the modem.
AT+CGATTUsed to activate and deactivate GPRS or PS (Packet Switched) connection. AT+CGATT=0 deactivates, and AT+CGATT=1 activates GPRS.

References on AT Commands

  1. www.3gpp.org/ftp/Specs/html-info/27-series.htm
  2. ETSI GSM 07.07 AT commands, GPRS
  3. ETSI GSM 07.05 AT commands for Short Message Service (SMS) and Cell Broadcast Service (CBS)

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