BYTES and WORDS aren't treated as signed variables which means things like IF A < 0 won't work properly but you can still do A = -3 and if you're putting the value on a LCD or something using the SDEC modifier properly handles a negative value.

If PBP doesn't allow you to put -3 in a lookuptabe simply put 253 in there instead (or 65533 if it's a WORD).

/Henrik.