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.
Overview
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.
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.
