I am interfacing wavecom M1306B & facing some problem.

1. Sometimes when I send a command like "AT\r", I don't get any response from wavecom.

Even if had 2 sec timeout for reception, after which I resend command but still don't receive anything from wavecom.


2. I have only used rx & tx lines of wavecom. do wavecom needs all pins of uart for interfacing like CTS, etc.

Edit:
When I connect it to PC & use teraterm it works fine. I don't know if teraterm is using all pins of DB9. Buy CTS bit in teraterm shows green flag

 

Datasheet says we have to use flow control:hardware.

But I have triedin hyperterminal without flowcontrol i.e None, it works fine.

Should I ground CTS pin of modem to ground. There is 7V coming there.