AT COMMANDS FOR GSM MODEM

HAI
i am facing two problems.
1. i have gsm modems which have no IMEI NUMBER imported from taiwan.i have to programme IMEI NUMBER IN the modems.what are the AT commands used for the purpose.this is very urgent.any idea.
2. some gsm modems have INVALID IMEI NUMBERS, i have to programme new VALID IMEI NUMBERS, what are the AT commands used for the purpose.

The IMEI number consist of two fields. The first field identifies the manufacturer, the second is a serial number. It's much like the MAC address of an ethernet board. How will you choose the IMEI to use as you don't have a valid manufacturer ID.

There are no standard 'AT' command for setting these values as it's something that should be done by the manufacturer. Some devices allow you to set this using a special program. You'll have to obtian that information from the manufacturer.

The data card most likely acts as a modem, and most GSM modems support the ETSI GSM 07.07 standard.

You should get the IMEI by issuing AT+CGSN:




Request product serial number identification +CGSN

+CGSN action command syntax

Command Possible response(s)
+CGSN <sn>
+CME ERROR: <err>
+CGSN=?

Description

Execution command causes the TA to return one or more lines of information text , determined by the ME manufacturer, which is intended to permit the user of the TA to identify the individual ME to which it is connected to.

Typically, the text will consist of a single line containing the IMEI (International Mobile station Equipment Identity) number of the ME, but manufacturers may choose to provide more information if desired. Refer subclause 9.2 for possible <err> values.
Defined values

<sn>: the total number of characters, including line terminators, in the information text shall not exceed 2048 characters. Text shall not contain the sequence 0<CR> or OK<CR>


try links below ,if helpful let me know.

www.communica.se/multitech/gprs_at.pdf

http://en.wikipedia.org/wiki/Hayes_command_set

www.arcelect.com/GSM Developer Guide - GSM AT Commands - Rev A.pdf

http://www.txtonline.com/sms_at_commands.htm