Hello all, Apologies if you have seen this already, but we've just swapped our = network and provider so lot's of e-mails have gone blindly into = cyberspace never to be seen again! Can anyone give me a little help with regards to programming a PIC for a = radio data modem application. I have written the code to convert a set = of parallel inputs into a series of data for transmission and have = formed the data stream such that the packet structure is ,, but talking to someone they mentioned that in order to = maintain data integrity I should implement a Checksum at the end of the = data stream for error checking. Unfortunately I don't have any previous = experience in radio protocols and don't know how to implement this into = the PIC code, can anyone give me a further insight into how this works = and possibly some code samples to determine the manner in which this is = incorporated. Many Thanks Robbie Banks Design Engineer Axiom Process Ltd. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.