sigal@ucscb.UCSC.EDU (60517000) (02/10/89)
Howdy, I am having a bizarre problem with my Compaq Deskpro 286 (8 mhzt - old model). It appears that the built in serial port (COM1:) is holding Carrier Detect (CD) high all the time. I just purchased a new modem (Zoom Telephonics 2400baud external), and attached it to my COM1 port. [Previously I had an internal modem set for COM2:.] The Zoom modem is fully Hayes (r) compatible, and has the full set of 8 lights on the front. According to the modem manual, CD is (by default) on only when carrier is detected. The light on the front of the modem appears to confirm this. I have also played around with forcing CD always on (with AT&C0) and this appears to affect the CD LED correctly. However, one of my communications packages (The Equalizer from Charles Schwab) is barfing with this modem. According the Schwab folks, The Equalizer will only work if CD reflects the true state of the carrier. So, I started poking around, and downloaded two (terrific!) programs: BRKBOX and COMHELP. Each of these two COM port diagnostic programs confirmed that as far as the computer was concerned, CD was always ON! Well, I was checking out the connections on my modem cable, when I noticed that these diagnostic programs said that CD was on even when the cable was disconnected! So it must not be the modem, right? Well, in trying test after test it became more and more clear that the problem was in the serial port itself, and not in my modem nor the cable. So now I'm stumped! Does anyone know anything about the serial/parallel card that was shipped in the early model Compaq Deskpro 286? Have you heard of this problem before? Is there some jumper that needs to be set? Confused and seeking Guidance Andrew Sigal internet: sigal@ucscb.ucsc.edu or bitnet: sigal@ucscb.ucsc.bitnet