Thanks Brian. Turns out your cable links weren't in my thread at all. They were in a different thread completely which I wasn't part of, and wasn't following.
Here's the situation. Those two cables you recommend in that other thread are null modem cables. Fine - but I've already learned the problem I have is with my usb/serial cable. Soon as I plug it into the 102, the 102 screen dims, which may be caused (I've been told) by crossed wiring in that cable. So, even if I do buy another cable (one of the null modem cables), I'd still need some kind of usb/serial "converter/adapter". There's no usb on the recommended null modem cables, and there's no serial port on the Dell laptop or desktop. Thanks. Tom M. On Wed, Apr 10, 2019 at 12:39 PM Brian White <[email protected]> wrote: > In one post, I provided a link directly to two items, a specific cables2go > cable and a specific sabrent usb-serial adapter, so that you wouldn't have > to make sense of the full page where that info came from. > > And also linked that full page, which includes the startech and others. > > http://tandy.wiki/Model_100_102_200_600_Serial_Cable > > I know reading that full page might not make 100% sense, because it's a > lot of verbiage, and there are many cables listed there and they all work > for this so how do you choose, and some parts are kind of cryptic, which is > why I pulled out the two parts to get. > > For instance the shorthand I used to document each cables wiring > idiosyncracies, like "DCD<>DSR+DTR", I know that part is cryptic. When I > was testing cables and assembling the info, I just needed to get the key > details written down, and the form didn't matter. I could expand it to be > more readable later. > > What those little things are showing is how each particular cable differs > from the rs232 spec. > > For instance "DCD<>DSR+DTR" means that dsr and dtr are tied together on > one end, and connected to dcd on the other end, and that it's the same on > both ends in both directions. All other connections are according to the > rs232 spec, and you get the pin numbers and positions from the rs232 spec. > > Some time when I want to spend more time on that page, I can expand those > to a less cryptic form, (or anyone else can, it' s a wiki) but until then > at least the knowledge is documented so that later I can refer to it. It's > sort of like working notes until then. > > Mike Stein also provided a direct link to a specific monoprice cable. That > one is good too. (it's on that page too for instance) > > All other cables you randomly find from wherever, probably aren't right > without some kind of adapters, and there is no way to tell if the wiring is > right except by knowing the rs232 spec and testing the connections. > > rs232 is not a single thing, it's a spec with a bunch of options and > configurations. In order to use anything serial, you the user, actually has > to understand that spec, or, you have to take the word of someone else who > does, and says "this specific cable will work for this specific > application". Plugging in any old cable without knowing how it's wired or > what the different rs232 signals are for and how they work, will never > work. Serial is not like usb or ethernet or headphones. > > For another example of ehat I mean, even when you finally get a correct > serial cable for connecting your m100 to a pc, that cable won't be correct > for connecting to a modem, or a plotter, etc. 3 different devices, 3 > different cables, and yet all of them are valid correct serial cables even > though they are all different from each other. > > The only way to make it work is to understand that and go read about > serial cables so that you know enough that you could build your own from > scratch, or continuity test any off the shelf cable to fully understand > what it does. Or, buy one that is already known to be correct for this > particular task. > > -- > bkw > > > > On Wed, Apr 10, 2019, 7:30 AM Thomas Morehouse <[email protected]> > wrote: > >> Brian - you wrote: >> >> " >> >> The Cables2Go one I linked is all the same, except it also has rts/cts, >> so it works with HTERM, as well as everything else. >> >> And finally, the StarTech one I linked, is also all the same, but >> without shorting DCD to DSR, or shorting DTR to DSR, which means that >> one should cause the least possible drain on any possibly weak power >> rails in the M100. >> >> All this mystery has already been completely figured out and nailed >> down. One mouse click and $7 later and you're done." >> >> I've gone through all your posts in this thread, and find no links for >> Cables2go or StarTech. >> >> I'm absolutely going nuts here, trying to figure out how to do things, >> and how to follow advice. One post with advice raises a question, someone >> else tries to answer the question, then someone else tries to clarify the >> answer to someone else's question. Really helpful to some, but frustrating >> to me. >> >> Which post had those two links for the proper cables? I've now got two >> usb/serial cables which don't seem to work, plus several male/male, >> female/female, and DB9 to DB25 adapters. Total so far: $100. >> >> As I can't find the links Brian referred to, I don't want to guess and >> buy yet another thing which might not work. >> >> Thanks. >> Tom M. >> >> >> >> >> On Tue, Apr 9, 2019 at 9:34 PM Kurt McCullum <[email protected]> wrote: >> >>> Tom, >>> >>> Looks like you will need to either build or buy a cable. My two cents is >>> below but I'm sure others will chime in. There are several options out >>> there. >>> >>> Here is a description of what I do with all my Model-T units. I start >>> with this DB25 to DB9 adapter which is just a regular DB9 to DB25 >>> converter. I attach these with some 2.5mm (should be 2.6mm) screws to the >>> Model-T so its always attached. >>> https://www.sfcable.com/db9-female-to-db25-male-serial-mini-adapter.html >>> >>> Then I put one of these adapters in between the DB9 serial port and the >>> 9-25 adapter which creates a null modem cable. >>> >>> https://www.sfcable.com/null-modem-adapter-db9-db25/db9-male-to-female-null-modem-mini-adapter.html >>> >>> For my T200 I have remove pin 1 from the null modem adapter to make it >>> happy but that's a quick fix with needle nose pliers. >>> >>> Everybody has there preference on cable setup so eventually you will >>> come up with a solution that works for you. Sounds like what you have is >>> working for text transfers so that's a start. >>> >>> Kurt >>> >>> >>> On Tue, Apr 9, 2019, at 5:59 PM, Thomas Morehouse wrote: >>> >>> Thanks Kurt. >>> >>> Testing the DB9-DB25 adapter only - not the usb/serial cable - I have >>> continuity NOT from pin 4 of the DB9 to pin 6 of the DB25. I have >>> continuity from pin 4 of the DB9 to pin 20 of the DB25. That's using the >>> numbers printed at the pins themselves. >>> >>> Should I even bother testing the others you suggest? Sounds like the >>> adapter already fails the test. >>> >>> Tom M. >>> >>> >>> On Tue, Apr 9, 2019 at 8:48 PM Kurt McCullum <[email protected]> wrote: >>> >>> >>> Ignore the USB to serial piece of the puzzle. As Brian said, it's just a >>> serial port. Test the 9 to 25 adapter. One end will be female so it's >>> easier to put something like the end of a paper clip into one hole at a >>> time then put the probe on that. >>> >>> Kurt >>> >>> On Tue, Apr 9, 2019, at 5:22 PM, Thomas Morehouse wrote: >>> >>> OK - looks like I wasn't clear. In Kurt's post, he writes: >>> >>> "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." >>> >>> If the usb/serial cable is a single unit (usb at one end, DB9 at the >>> other), how do I put one probe of the meter on the DB9 and the other probe >>> of the meter on the DB25? There's no DB25 on the cable, unless I plug the >>> 9-25 adapter into the DB9 - but then I can't put a probe on the DB9. Jeez >>> I feel dense. >>> >>> I'm really sorry I can't follow this, but maybe I'm just overlooking >>> something really simple? >>> >>> Thanks. >>> Tom M. >>> >>> >>> On Tue, Apr 9, 2019 at 7:56 PM Brian K. White <[email protected]> >>> wrote: >>> >>> You don't check continuity on the usb-serial adapter. That isn't just a >>> cable, it's really a peripheral like a disk drive or a printer, it just >>> happens to be a peripheral that all fits entirely inside the plug >>> housing on one end of it. There is no simple direct wire mapping between >>> the usb pins and the serial pins. Between the usb pins and the serial >>> pins, there is circuit board with a chip and a few other components >>> which is converting and translatine between two entirely different kinds >>> of signals and protocols. >>> >>> You treat the usb-serial adapter as just a serial *port*, and ignore >>> that it looks like a wire. Just pretend it's like a serial port built in >>> to the back of an old desktop. >>> >>> You check the continuity of the serial cable, which IS "just a cable". >>> Or, really, you check the continuity of the combined serial cable with >>> any null-modem and gender-changer adapters, and treat that all together >>> as one "cable". >>> >>> -- >>> bkw >>> >>> On 4/9/19 6:56 PM, Thomas Morehouse wrote: >>> > 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] >>> > <mailto:[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] >>> >> <mailto:[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. >>> >>> >>> >> >>> > >>> >>> >>> >>>
