If you want the other software developers to pick up encryption then you had better put it into some kinda kit or TPU. That is the easiest way to get those other people like Mustang Software to add hooks into their software. If you distributed some kind of TPU to add onto Async Pro then you just made it really easy to add encryption onto a couple of BBS packages. If you were to make a TPU I think you should have the code to handle file encryption and stream encryption built into it. For Async Pro you could just make up a send_cipher function that encrypts the data then calls Async Pro's serial send function. I also think it would be better to come up with some freeware so people don't have to go buy Async Pro, but that would be a good quick cipher engine for PC serial IO if you just added onto Async Pro without worrying about the serial routines for the moment also. d. saint