Hi all, Firstoff, my thanks to those who emailed source code and hints and tips on getting that damn 16c74a RS232 serial code to work - unfortunately, this was a case of technology being no match for stupidity - I assumed the Thurlby PSU I had would have adaquate grounding and it turns out that it doesn't ! Once that was fixed, the code ran like a dream. I'm now busily kicking myself for forgetting the one thing I thought amateur radio would have taught me - always check your ground when doing communications !!!!! :) Now, on to that pesky LED display ! -- Mark Dennehy, B.A., B.A.I. Email : mdennehy@tcd.ie Research Student, Computer Vision and Robotics Research Group, Computer Science Dept., Trinity College Dublin