slippyr4 wrote: > The logic behind it is a bit > beyond my understanding of electronics Break it down a piece at a time. Do you know what a single pole R-C filter is? If so, you should be able to see that this is three of them in succession. ******************************************************************** Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products (978) 742-9014. Gold level PIC consultants since 2000. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist