AT Commands

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Created: vasant21 (12 May 2007)
Last edited: hamishwillee (22 Jul 2013)


What you should know

Different phones support different sets of AT commands. This means that a specific phone might not support all AT commands listed below. Currently there is no authoritative list available of supported AT commands by all phones.

Note.pngNote: Windows Phone supports a very limited set of AT Commands (and these are not documented here.)


AT commands are also known as Hayes AT commands. There are different views to understand the meanings of "AT". Some call it "Attention Telephone", whereas others interpret it as "Attention Terminal" commands. A Hayes Microcomputer Products, where it was invented, AT was merely short for "ATtention"

AT commands allow giving instructions to both mobile devices and ordinary landline telephones. The commands are sent to the phone's modem, which can be a GSM modem or PC modem. This article focuses on AT commands on Nokia's GSM and WCDMA products only. Different manufacturers may have different sets of AT commands. Fortunately, many AT commands are the same. Mobile device manufacturers may also give attention to operators to allow or not to allow some commands on phones.

AT commands can be used for operations that are usually done from the keypad, for instance calling a number, sending, reading, or deleting an SMS, setting the SMSC number, looking for a GPRS access point, reading and deleting phonebook data, reading the battery status, reading the signal strength, and so on. When you want to make a PC-based application to interface a mobile phone using USB, IR, or Bluetooth, these commands are needed to communicate with mobile phones. Basically such commands are the application layer of MBUS or FBUS commands. Nokia provides an AT command set guide, where you can see the basic command syntax and the response of the command in various situations. See the Related Links section at the end of this article).

Using AT Commands with HyperTerminal

AT commands work on devices that have a built-in GSM modem. If there is one, you do not need to install virtual modem software on your PC. If you are using very old Nokia devices, you have to find out the DATA suite, not the PC Suite, for these devices (such as the Nokia 5110) to be able to use AT commands. This article focuses on mobile devices that have a built-in GSM modem.

To use AT commands:

  • Connect the mobile phone to your PC in PC Suite mode using any available connection (Bluetooth, USB, or IR).
  • Make sure that you have installed the correct GSM modem driver on your PC. You can check it from Control Panel | System | Hardware | Device Manager. Check the Modems section. If you see something like "Nokia XY USB Modem" or "Nokia XY Bluetooth Modem", the device has a built-in GSM modem. If you don't have it, go to the Nokia Web site and download the driver from the product page of your device.

Controlpanel gsmmodem.png

  • Right Click on Nokia N95 8GB USB Modem and find the port used by selecting the modem tab, in our case it is COM 4. Also it is good to test the modem by selecting Diagnostics | Query Modem, this will tell us if the modem is working properly.
  • Open the HyperTerminal, which is a communication utility on Microsoft Windows OS. HyperTerminal is located in Start | Programs | Accessories | Communication.
  • Create a new connection set on HyperTerminal and give a name to the connection.
  • Select the port number by seleting drop down box "Connect using". In our case the port number is COM 4


  • You need to select some settings related to ASCII setup, To do select File | Properties | Settings (tab) | ASCII Setup


  • You may need to set some parameters, such as baud rate (for example, 9600), handshaking mode (Xon-Xoff), parity bit (default), and so on.

Hyperterminal settings.png

  • Note that you also need to select the communication port on which your mobile has been connected. The port number can be found by right-clicking the modem item in Control Panel.

Controlpanel gsmmodem port.png

  • After this, you can give the basic AT command. Simply type AT in the window and you will get the "OK" response.

Hyperterminal example.png

The above picture also shows how to dial a number using the ATD command. Note that there is a semi-colon (;) at the end of the phone number indicating that this is a voice call. If there is no semi-colon, a data call (CSD call) is will be performed.

AT commands set for Nokia GSM and WCDMA products

Call control

Command Description
ATA Answer command
ATD Dial command
ATH Hang up call
ATL Monitor speaker loudness
ATM Monitor speaker mode
ATO Go on-line
ATP Set pulse dial as default
ATT Set tone dial as default
AT+CSTA Select type of address
AT+CRC Cellular result codes

Data card control commands

Command Description
ATI Identification
ATS Select an S-register
ATZ Recall stored profile
AT&F Restore factory settings
AT&V View active configuration
AT&W Store parameters in given profile
AT&Y Select Set as powerup option
AT+CLCK Facility lock command
AT+COLP Connected line identification presentation
AT+GCAP Request complete capabilities list
AT+GMI Request manufacturer identification
AT+GMM Request model identification
AT+GMR Request revision identification
AT+GSN Request product serial number identification (IMEI)

Phone control commands

Command Description
AT+CBC Battery charge
AT+CGMI Request manufacturer identification
AT+CGMM Request model identification
AT+CGMR Request revision identification
AT+CGSN Request product serial number identification
AT+CMEE Report mobile equipment error
AT+CPAS Phone activity status
AT+CPBF Find phone book entries
AT+CPBR Read phone book entry
AT+CPBS Select phone book memory storage
AT+CPBW Write phone book entry
AT+CSCS Select TE character set
AT+CSQ Signal quality

Computer data card interface commands

Command Description
ATE Command Echo
ATQ Result code suppression
ATV Define response format
ATX Response range selection
AT&C Define DCD usage
AT&D Define DTR usage
AT&K Select flow control
AT&Q Define communications mode option
AT&S Define DSR option
AT+ICF DTE-DCE character framing
AT+IFC DTE-DCE Local flow control
AT+IPR Fixed DTE rate


Command Description
AT+CLIP Calling line identification presentation
AT+CR Service reporting control
AT+DR Data compression reporting
AT+ILRR DTE-DCE local rate reporting

Network communication parameter commands

Command Description
ATB Communications standard option
AT+CBST Select bearer service type
AT+CEER Extended error report
AT+CRLP Radio link protocol
AT+DS Data compression

Miscellaneous commands

Command Description
A/ Re-execute command line
AT? Command help
AT*C Start SMS interpreter
AT*T Enter SMS block mode protocol
AT*V Activate V.25bis mode
AT*NOKIATEST Test command
AT+CESP Enter SMS block mode protocol

SMS commands

SMS text mode

Command Description
AT+CSMS Select message service
AT+CPMS Preferred message storage
AT+CMGF Message format
AT+CSCA Service centre address
AT+CSMP Set text mode parameters
AT+CSDH Show text mode parameters
AT+CSCB Select cell broadcast message types
AT+CSAS Save settings
AT+CRES Restore settings
AT+CNMI New message indications to TE
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


Command Description
AT+CMGL List Messages
AT+CMGR Read message
AT+CMGS Send message
AT+CMGW Write message to memory

Related links

This page was last modified on 22 July 2013, at 04:27.
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