Thanks Kurt. I'm even denser than usual tonight I guess. >From earlier posts, seems the problem (102 screen dimming) is likely caused by the usb/serial cable. One end of the cable is a usb plug; other end is the DB9.
So I'm afraid I don't know how to test continuity on the cable. I can find pin 4 of the DB9 - but where does the DB25 fit in the picture? Or, are you saying to test the cable with the DB9/DB25 adapter plugged into the cable? Sorry to be the dolt again. Tom M. On Tue, Apr 9, 2019 at 10:57 AM Kurt McCullum <[email protected]> wrote: > There are store bought cables that work well. Brian has done a great job > putting together a list of those cables. For my machines I have a mixture > of custom made cables or slim adapters. Both methods work and give me the > pinout below. When you get the cable right, your M102 will be happy. > > But to the question at hand, don't tear apart your cable. Check it. Right > now you know that pins 2,3 and 5 are all going to the right locations. You > will need to check pins 4,6,7 and 8. Since those are paired lines (4/6, > 7/8) one or both pairs will be flipped. > > If you have a multi-meter which has a continuity check on it then you test > both ends of the wire. > > Here is what I have found to work on all my machines and I include this in > the mComm manual. > > 7 Wire Cable > PC > > Model-T > DCD > 1 > NC > > > RX > 2 > → > 2 > TX > TX > 3 > ← > 3 > RX > DTR > 4 > ← > 6 > DSR > GND > 5 > ↔ > 7 > GND > DSR > 6 > ← > 20 > DTR > RTS > 7 > → > 5 > CTS > CTS > 8 > ← > 4 > RTS > RI > 9 > NC > > > > Take one probe of the meter and put it on pin 4 of the DB9 and the other > on pin 6 of the DB25. It should beep or light up (however you meter > functions to indicate a connection). Then do the same for the DSR line on > pin 6 to pin 20. And finally the RTS and CTS pins 7->5 and 8-> 4. If they > are crossed in some manner, then you will not get a beep or a light. > > Hope that makes sense. > > Kurt > > > On Tue, Apr 9, 2019, at 7:38 AM, Thomas Morehouse wrote: > > Thanks for the comments gents. Learn something every day. > > Kurt, on the "crossed wires" issue, what is the procedure for fixing the > problem? I sure don't want to pull something apart, or buy even *more* > adapters! > > Thanks. > Tom M. > > > On Tue, Apr 9, 2019 at 10:03 AM Kurt McCullum <[email protected]> wrote: > > > What you are describing happens to me when the either the CTS/RTS or > DTR/DSR wires in your cable are crossed. > > Example. The CTS pin listens (checks for voltage) to the RTS pin on the > other end. If you have a cable where RTS goes straight to RTS and CTS going > straight to CTS, then you have two ends of the cable both feeding voltage > to the same wire. This causes the screen to go dim. the DTR/DSR pins can > produce the same issue. > > Kurt > > On Tue, Apr 9, 2019, at 5:33 AM, Thomas Morehouse wrote: > > Now that I've got my usb/serial link working (M102 to Dell laptop), I > notice the 102's screen get quite dim when the cable is in the 102's 25 pin > serial port. > > Doesn't need to be connected to the Dell. Just when you plug the > usb/serial cable into the 102. Unplug the cable, 102 screen returns to > normal visibility. > > Something to worry about? or just live with it? I wouldn't have thought > the usb/serial cable chip would put such a drain on the system. Happens > with battery power, or even with external 6 volt poweer. > > Thanks. > Tom M. > > > >
