But some people round here can't seem to help themselves when it comes to a little slap over the head. I don't mind, sometimes I need it. I think I'll let this post lay for a while and see if anyone has any advice. But I'm thinking SHIFTIN might work, then i'll have to figure out a way to clock in and count the number of incoming bits or bytes. The preamble alone is 16 bytes of $AB repeating. Then the message itself, which is what i want to decode, can be up to 268 bytes long. but it is supposed to always start with ASCII ZCZC to let you know the message is starting, then wait for "NNNN" which is the end of the message. Everything is delimited with a "dash", so it shouldn't be so hard to break the message down. I've never worked with SHIFTIN before, and know nothing of interupts, so if anyone has any advice or a better way, let me know!