Thanx tong

but i'm already familiar with using at commands,what u sujjested me i have already done,even i have used 8051 on Keil.i know how to program it for serial communication.
but the problem here is ,i'm not getting how to use at commands in C programming for 89C51,to talk to modem,i mean to initiallise the modem and then to send and receive the data.
i have already done with the at commands and even got the communication bte 2 modems,i send the data and got the same data on the other side,i checkecd this but now through microcontroller is the main problem.
can u help me now,in doing this.

can u give me ur e-mail id so that i can be in touch.if it is o.k. with u.i'll be greatful for the help.

regards
minal.