I have been struggling for weeks with an issue, it seems like I gone to every possible solution except threading. I have spent some time over the weekend looking for an example of simple comms using threading. It seems like I am using a seperate thread with the delegates from Serial Port Complete Chapter 10 (Managing Ports and Transfers in .NET) but want to make sure. Belt & Braces defense against the board/firmwares designer reply "learn to do Serial comms properly" in front of the Boss, while scurrying off to fix problem. Politics Abound with this project!