David Dyer-Bennet wrote: > Jumping 5 or 6 or 8 to 20 doesn't do anything (other than lighting the > light associated with 5, 6, or 8 on the breakout box). But it isn't > detected either by my program or by the UPS monitoring programs I've > tried. > > When I run my monitoring program it reports one value, then instantly > another value, then never reports a change again. The initial change > is *before* I do anything to make a change at the breakout box. It > very probably represents some sort of bug in the program, possibly > even a bug that makes the whole test invalid; I just haven't figured > out what it *is* yet. > > If I control/c out, and then run it immediately again, I get exactly > the same behavior (and exactly the same values), which I take as > additional evidence that the output isn't responding to reality. Try this David, tie pins 4 + 5 to the computer together and test again. Most of the newer computers (post Pentium) need 4+5 jumpered or 5 connected to something else for the serial port to function. I would'nt think you would need this just to scan the port but maybe........... John