> David Dyer-Bennet wrote: >So, on the connections -- I've tried connecting pin 20 (DTR; light >showing red for negative voltage) to various things both direct and >through a 4.7k resistor. I've also tried grounding the other things >(to pin 7, SG). The way I see it you could use pins 5,6,8 (db-25) for monitoring, being they all set above ground. Your open collector outputs on the ups will take these to ground on a state change. But does your computer need to see a rs-232 low ( that is negative) to register a change? Your ups can't do that directly. Jumpering 5 or 6 or 8 directly to 20 will do this. See if that works for your program as a test. You also mentioned it worked once, did you mean the program the first time you run it? John