Communicate with PC at baud rate :115200 bps

[skimask]

But i always use 115200 Baud in nokia 3350 sms zone alarm with this code.

Well, that'll work too, because you're using the HARDWARE USART.
The note at the back of the book is for SERIN(2)/SEROUT(2).
The O/P didn't specify if hardware or software serial was being used...