> 3. It's a CRC or the complement of a CRC, in which case there are > only 16 possible polynomial nybbles to use. Yes, only 16 polynomials, but also 16 initial values and 2 bit orders and several possible starting locations in the bitstream and .... -- Bob Ammerman RAm Systems -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist