RFModem AT Commands Explained
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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 command | Description |
|---|---|
AT | Used to check communication between the module and the computer. |
AT+CMGF=<mode> | Sets the SMS mode (PDU mode or text mode). |
AT+CMGF | Message format |
AT+CMGL | List messages |
AT+CMGR | Read message |
AT+CMGS | Send message |
AT+CMSS | Send message from storage |
AT+CMGW | Write message to memory |
AT+CMGD | Delete message |
AT+CFUN=value | Sets 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. |
ATA | Used to answer an incoming call. |
ATH | Used 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=1,2,26201 | Manual PLMN (Public Land Mobile Network) selection. |
AT+COPS? | Provides PLMN information set in the modem. |
AT+CGMR | Displays the version of the software loaded on the modem. |
AT+CGATT | Used to activate and deactivate GPRS or PS (Packet Switched) connection. AT+CGATT=0 deactivates, and AT+CGATT=1 activates GPRS. |
References on AT Commands
- www.3gpp.org/ftp/Specs/html-info/27-series.htm
- ETSI GSM 07.07 AT commands, GPRS
- ETSI GSM 07.05 AT commands for Short Message Service (SMS) and Cell Broadcast Service (CBS)
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