I have a simple "parallel port logic analyzer" (PCLA) that I wrote some time ago. It gives you 13 channels (assuming you have a bidirectional parallel port), and a sample rate of around 500khz (depends on the machine) Above 486ish the CPU doesn't matter much, it's the I/O setup which limits it. Allows you to set trigger conditions (0, 1 or X=Don't care), captures 255 samples before the trigger and 65536 samples after the trigger. Which you can scroll around and review. Has functions to search for data patterns and the usual stuff. Runs under DOS, I'll give it to anyone from the list that wants it - just drop me a line. Dave -- dave06a (at) Dave Dunfield dunfield (dot) Firmware development services & tools: www.dunfield.com com Collector of vintage computing equipment: http://www.parse.com/~ddunfield/museum/index.html