how to use at command in c programming of keil compiler . i use 89s52 micro controller . my concept is if any fire accident occurring in my home means it send sms to me . so please send program to my email id (rk9047545247@gmail.com)
"My question is whether this AT command is common for all type of gsm modum"
That question has nothing whatsoever to do with the 8051, or Keil, or 'C' source code!
If that's your question, what was the point in burying it in illegible source code?
You can find the answer to that question by studying the GSM Standard AT Command documents:
07.07 - AT command set for GSM Mobile Equipment www.3gpp.org/.../0707.htm
07.05 - Use of DTE-DCE Interface for Short Message Services (SMS) www.3gpp.org/.../0705.htm
"I will wait for your reply"
Don't just sit there waiting - start doing some research of your own!
There's plenty already out there; eg, www.8052.com/.../161632