prakash,

If you search the site you will find a lot about modem handling and modem initialization.

Andy's approach is very helpful because it will give you insight into handling your "specific" modem which can often cause you to handle things a tad differently than a generic modem approach would suggest.

Some things to consider:

1) Prior to establishing a call, hardware reset your modem;
2) Don't be surprised if a hardware reset causes "residual or bad characters" to emanate from the modem";
3) consider using numeric codes "ATV0" and turning off echo "ATE0".

regards,
p