Need help with GSM technology

[hdaroga]

Hi guys, i need some help.
i hav to make a transciever that uses a SIM card just to send a particular signal. the transciever should be exteremly small just like an Rf id tag. it should be capable of recieving a signal and then transmitting another one to the service provider

 

[rajat]

friend i feel you can use the readialy available GSM module that will serve your cause