Hi all, firstly thanks to all who responded to my question. I never thought it would be as complicated a topic as it appears to be! As I probably don't need super accuracy I am going to try a couple of 22pf caps and see if they work. Basically if I can get serial coms working at 9600baud on my 20mhz 16F628 then I'll be happy. The more recent posts on this tread have been somewhat over my head, but have certianly been interesting reading! Thanks again, James Fitzsimons. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.