I have interfaced gsm sim300 module with at89s52. My gsm module works efficiently with hyperterminal.. But it doesn't work with controller. To verify my controller ckt i interfaced it with my frnds gsm module. Then it works properly.. Can any one help me get out of this ???? What can be the problem with my gsm module???
You should consider many things even the GSM modules are same.
First read the configuration of your friend's GSM module by AT command.
Then read yours and compare.
you will find some commands in AT command manual of SIM300. i.e AT&V