A serial port normal does supply power, so it does produce a drain. On Wed, Apr 10, 2019, 12:09 PM Stephen Adolph <twospru...@gmail.com> wrote:
> fwiw, I usually see the LCD change it's bias when I plug in serial. > > On Wed, Apr 10, 2019 at 1:03 PM Kurt McCullum <ku...@fastmail.com> wrote: > >> Is your current USB to serial adapter an entire cable? For example, one >> side is a USB plug and the other is a DB25 male plug? With no other parts >> in between the two? >> >> Kurt >> >> On Wed, Apr 10, 2019, at 9:54 AM, Thomas Morehouse wrote: >> >> Thanks Kurt. But we already know that my current usb/serial adapter >> (which is a single unit usb/serial cable) cause the 102 screen to dim. In >> other words, that's where the problem is. >> >> So I don't see how a new null modem cable plugged into my faulty >> usb/serial adapter/cable will help the situation. >> >> Tom m. >> >> >> On Wed, Apr 10, 2019 at 12:51 PM Kurt McCullum <ku...@fastmail.com> >> wrote: >> >> >> Tom, >> >> The cables that Brian is recommending will attach to your existing usb to >> serial adapter. So the connection would work as follows. >> >> Laptop USB Port -> USB to Serial Adapter -> DB9 to Db25 Null modem Cable >> -> Model T >> >> Kurt >> >> On Wed, Apr 10, 2019, at 9:46 AM, Thomas Morehouse wrote: >> >> 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 <bw.al...@gmail.com> 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 <nutmegfl...@gmail.com> >> 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 <ku...@fastmail.com> 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 <ku...@fastmail.com> 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 <bw.al...@gmail.com> 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 <ku...@fastmail.com >> > <mailto:ku...@fastmail.com>> 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 <ku...@fastmail.com >> >> <mailto:ku...@fastmail.com>> 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. >> >>> >> >> >> > >> >> >> >> >> >>
