HI Jan-Erik: I have a web page that lists the common crystal (unit oscillator) frequencies and shows the factors and typical use. See: http://www.pacificsites.com/~brooke/Images/Crystal_Freq.html Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist