In AN833 page3 we have CLOCK_FREQ TICKS_PER_SEC TICK_PRESCALE Can someone help me to choose vaues for them. My internal clock is 8mhz, and my slip will be 19200. tia -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist