sim800a gsm module not working

[T.mohan]

When i connected Sim800a gsm module to serial port and when i press reset button it receives message cpin ready...sms ready etc.but when i try to communicate with AT commands its not working?i checked for all the baud rates..for 9600 baud rate when i press reset button i get message but if i send AT command i did not get any reply from module..what is the problem dont know?please anyone help me to getout from that problem.?

 

[kellys_eye]

What settings are you using for parity and stop bits?

 

[(*steve*)]

It also might be worth checking the voltage levels required. These days TTL levels are usually fine, but that's technically not RS232, so the requirements might differ.

 

[T.mohan]

What settings are you using for parity and stop bits?

8 data bits, no parity, one stop bit