Thank you for your interest Melanie. I had started to think that nobody would reply. Sorry for insufficient info! I have been using 4 MHz xtal oscillator. You are right serial ouput procedure with Hserout is dependent to ascillator performance, but Hserin is also dependent to ascillator. Hserin performs normal but Hserout does not. The most confusing point for me is that.
I will try with 300 baud as you recommend. If you have any other comments on the problem, I will be pleased to hear them.
Thanks....