Siemens M1 manual Technical reference section AT standard, AT command line prefix

Technical reference section

The AT standard

With the development of intelligent modems, an command language was introduced in the U.S. called the AT standard. Over the past few years, this language has been con- sistently enhanced and has gained international acceptance. Most modems and com- munication programs work with this command language or can be set to use it.

AT command line prefix

The AT standard is a line-oriented command language. Each command line must begin with the letters AT, with the sole exception of the A/ command. The commands are in- troduced at the end of this section. The letters AT are also known as the attention code. The attention code signals your GSM module that one or more commands will follow. The GSM module examines this command line prefix.

Connecting to your GSM module

You have connected your GSM module to your PC. You can now connect to your GSM module. To do so, start up a communication program on your PC.

Set the following transmission parameters (characteristics):

COM interface:	1 - 4, depending on which one the M1 is connected to
Rate:	2400 - 19200 baud
Data bits:	8
Parity:	None
Stop bits:	1
Duplex:	Full

The GSM module supports autobauding on the V.24 interface with transfer rates from 2400 to 19200 baud and the data format 8N1.

Command syntax of the AT standard

•Command lines must always begin with AT.

•Multiple commands can be combined on one command line. To improve legibility, you can enter spaces between the individual commands. The GSM module ignores these spaces.

•Commands that are specified in this manual with "0" in the last position can also be entered without this "0". Example: ATQ has the same effect as ATQ0.

•A command line must end with a <CR> character, which is entered by pressing "En- ter" on the keyboard. This fact will not be mentioned again in this manual.

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