AT commands for the K750i

Content

Since there is a vast number of commands available for the modem interface of the phone, it is quite hard to pick the most interesting ones out of the extensive official documentation. This page tries to show some highlights of this interface, but don't expect a complete reference - If you need such, try the Sony Ericsson documents.

• Retrieving phone information: Collect data about the device state
• Dialing Control: Dial numbers from your computer
• Media player: Take control of the multimedia software
• Key presses: Simulate action on the phones keypad
• UI Control: Influence and create user interface items on your phone

I also developed a C# class library named DisGUISE for these functions, which makes it easy to create applications using the phone as in- and ouput device.

Retrieving phone information

General device information

The most basic data can be gathered by using the ATI (I for information) command: Without additionals data (or with 0 appended), it just displays the phone model:

ATI0
Sony Ericsson K750

OK

Other numbers reveal different data, such as the software revision.

Power state

The command AT+CBC displays the current power state of the cellphone: It basically returns two numbers, the first one indicates whether the phone is connected to AC power or not, while the later reports the charging level of the battery.

Dialing Control

Of course the most basic task for a modem can be performed as well: Dialing a phone number is done with the command ATD, certain flags such as ATDT for tone dialing are supported, but have - since we are dealing with a mobile phone network - no real effect.

You might notice that a command like ATD0123456 produces the error message NO CARRIER: To be succesfull, a semicolon has to be appended to the phone number to be dialed.

Media Player

A running media player can be controlled by the AT command AT*SEMP:

So AT*SEMP=1 will start the playback of the running media player.

Key Presses

It is possible to emulate key events through two different commands: The older method is AT+CKPD, which takes a sequence of characters and simulates the pressing this key sequence.

The more recent one involves the command AT*EKEY: This command evokes one or multiple key events, and indicates whether the key has been pressed or released.

UI Control

One of the most interesting aspects of the modem interface is the creation and manipulation of user interfaces. With special commands, the phone establishs a user interface that sends its events back to the computer it is linked to. The main intention behind this technique is to enable extension hardware to interact with the user. The protocol employed is relatively easy and well documented, so it should be possible to program a custom microcontroller to use homebrew hardware with the phone.

AT*SEAM="Foobar"
*SEAM: 4401

OK

*SEAAI: 4401