According to prog. spec. checksum for 17c44 PMC mode is 0xE00F, but my calculation is 0xE10F. here is my code for SUMXNOR8 for (i=start; i>8; low = TempWord[i] & 0x00FF; hml = ~(high ^ low); SUM += hml; } am I wrong? thanks www.poboxes.com/f f