[CMOTD]

Sounds like more trouble than it is worth and now even more so with the mention of a parallel printer port, OMG stop using this outdated technology and avoid headaches and stress. Go buy TrackMate Infrared Lightbar and few other items, ditch this SCX Chrono thingie and install Race Coordinator and really enjoy your track and racing. 

There is nothing wrong with outdated technology so long as it works. Indeed many people actually prefer older stuff. I am no expert on TrackMate stuff but I do know it costs an arm and a leg.

Compare to my own timing system:
Ancient laptop running XP and Race Coordinator with sensors connected to parallel port. Total cost of sensor set up just a tenner and only four wires to solder up - Simples! It has been running my home track for over ten years and has never missed a beat with a complete absence of 'headaches and stress'. Please tell me exactly why should I junk it at this point in time? I installed a similar system on my local club track nearly 20 years ago and that is also still going strong as far as I know.