On Thu, 17 Sep 2009 01:47:37 -0400, Sean Breheny wrote: > Perhaps this is a crystal which is cut differently than the HF ones? > For example, the 32.768kHz watch crystals. Tuning fork like the 32.768KHz ones according to the specs: http://www.rapidonline.com/netalogue/specs/90-0258.pdf The HF ones are a different cut; AC and ACT are the two most common I think. I believe those codes denote the angle they're cut at; now if only I could remember that manufacturer's URL that did a good article on that...:( Regards, Pete Restall -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist