i must read sms messages with serin and the 4 Mhz internal oscillator. When i receive the sms , the pic must receive 4 caracters with this:
SERIN RX,N9600,consigne,sms,ordre,valeur
9600 baud with 4mhz internal crystal... no way... you need a faster crystal... 2400 baud is starting to push the limit. Sometimes if things are right, 4800.

Dwayne