thanks for reply.
how can i connect level converter in between modem and pic?now i connected
pic tx
modem rx
pic rx
modem tx
and connected max232 input pin(rx)
modem tx
max232 output pin(tx)
modem rx
ie, level convertr parallelly.
without connecting this max232, i can send sms in to mobile.
but the problem is response of modem is not going to pic