If you want to eliminate any mystery about your cables and adapters, get these two items.
https://m.cdw.com/product/C2G-null-modem-cable-6-ft-white/1153481 https://www.amazon.com/dp/B005SYQV9C/ Those are not random items but specifically tested and verified. The serial cable has the right connectors and the right wiring inside. The usb adapter is based on an ftdi chip. I personally purchased and tested everything on this page to find off the shelf items that worked for this specific use. http://tandy.wiki/Model_100_102_200_600_Serial_Cable Otherwise, what everyone has said so far is correct. Usb-serial adapters based on Prolific chips can be a problem. And the loopback idea is a good way to verify if the physical hardware is actually working, while eliminating variables. The basic way to diagnose any mystery is to eliminate variables by breaking up the problem into smaller parts and test the individual parts individually. When you hook up the cables to the t102 and try it, you are testing like a dozen previously unknown links in a chain all at the same time. If it works, then you proved all the links are good all at once. But when it doesn't work, you know nothing and it could be any of a dozen things. Maybe the usb adapter cable is based on a Prolific chip and maybe it's a counterfit chip and Prolific have made their driver intentionally not work with it. That's actually a thingvbeleive it or not. Or maybe there is some option not set right in teraterm, or maybe the serial cable or the combination of the cable and the null-modem adapter isn't wired the right way, maybe the T102 has a bad serial port, etc... So the loopback test tests teraterm, the windows usb-serial driver, the physical usb adapter, but without the T102 or the serial cable & null modem adapter. It cuts the total number of variables and links in the chain roughly in 1/2, so you can then eliminate about 1/2 of the potential problems and focus on the remaining 1/2, rather than just trying things at random and never knowing anything. If you short the Tx pin to the Rx pin, and configure teraterm to ignore both hardware and serial flow control, then you should be able to press any key, and you should see two copies appear in teraterm. One from the fact that by default tt will echo what you type, and a second one that went out the tx pin and came back in the rx pin. If you can do that, then you will have established that about 1/2 of the entire system is good. It will verify that the way your operation of teraterm is good, the usb-serial driver in windows, and the usb-serial adapter are all good to go. It takes about 1/2 of the unknows and makes them into knowns, and then you can confidently focus on the remaining much smaller list of unknowns, which would be the serial cable, null-modem adaper, the T102 serial port, and your operation of telcom or basic on the T102. If the loopback does NOT work, then we can confidently focus on THAT half of the chain and start testing those parts individually, like, trying a different usb-serial adapter, or trying the same adapter on a different computer, etc. Then you can do the same loopback test on the T102 also, that will prove that that serial port on the T102 is good, or at least mostly. It is possible for something to be marginal and maybe work for loopback and then fail when connected to something else, but don't worry about that until you get that far. But a few things have already been proven by doing that actual testing, such as, everything on that wiki page above, and that cable and usb adapter above. That cable IS ftdi-based, and the driver is automatically found by Windows and there is no question about maybe the chip is counterfeit and maybe the driver is intentionally refusing to run on it, and DOES work for this particular purpose of connection to a M100 or T102, and that serial cable has the right connections inside and the right connectors on the ends and doesn't need an added null-modem adapter. Basically, this process of diagnosis and trial & error is normal. Getting any rs232 device working pretty much always requires a little more familiarity with how rs232 actually works. It's not like ethernet or usb where there is only one correct way of wiring it, and you just plug it in and it works by itself. You have to know all about the many different ways a serial connection can be configured, both at the hardware and software levels, and you have to MAKE it work by making sure that all the parts of the connection are set up the same way. -- bkw On Fri, Apr 5, 2019, 10:08 AM Thomas Morehouse <[email protected]> wrote: > Thanks Josh. Being new to the "102-Windows" world, I just adopted the > parameters in the Telcom manual. > > I just tried a different serial to USB cable with the same null modem > adapter I used before. This time Windows doesn't even recognize the > insertion of the cable in the laptop. > > Regarding Prolific: I used the driver that came with the original > serial/usb cable. It was provided by Prolific, so that's why I'm using > that driver. As today's cable isn't recognized by Windows, I don't know > what driver to use, or just keep plugging away on the Prolific driver. > > When people say they've had poor luck with Prolific, are they saying with > a Prolific cable? or with a Prolific driver? > > Tom M. > > > On Fri, Apr 5, 2019 at 9:44 AM Josh Malone <[email protected]> wrote: > >> I've had better luck with Cool Term: http://freeware.the-meiers.org/ >> >> I'd also suggest to start without flow-control or parity turned on, so >> STAT57N1D. Is there a reason you're using parity and/or flow control? >> >> -Josh >> >> On Fri, Apr 5, 2019 at 9:32 AM Thomas Morehouse <[email protected]> >> wrote: >> > >> > Wow - after several weeks, sounds like I'd need to start over. >> > >> > On the FTDI link, I only see a chip on a board - not a cable. Are we >> saying I'd need to open the laptop and replace a chip on the m/board, then >> find new drivers? >> > >> > And if so, how would that affect the TeraTerm, the cable(s) and the >> null modem adapter that I've tried so far? >> > >> > Thanks. >> > Tom M. >> > >> > >> > On Fri, Apr 5, 2019 at 9:24 AM John Gardner <[email protected]> wrote: >> >> >> >> Yes, but tieing the TX & RX pins together physically tests >> >> >> >> the whole TX & RX path - And the convertor, on the PC >> >> >> >> side. Like Birt, I suspect your Prolific device. >> >> >> >> >> >> >> >> On 4/5/19, Thomas Morehouse <[email protected]> wrote: >> >> > John - isn't that the same as using half/full duplex? TeraTerm on >> Win10 >> >> > lets me "echo" sent characters; duplex on TELCOM lets me do the same >> on the >> >> > 102. >> >> > >> >> > Tom M. >> >> > >> >> > >> >> > On Fri, Apr 5, 2019 at 9:11 AM John Gardner <[email protected]> >> wrote: >> >> > >> >> >> You should be able to tie ("loop back") the TX pin of >> >> >> >> >> >> your convertor to the RX pin, so that sent characters >> >> >> >> >> >> are echoed to the display. Same deal on the MT side. >> >> >> >> >> >> >> >> >> >> >> >> On 4/5/19, John Gardner <[email protected]> wrote: >> >> >> > Been there, done that - I've had good luck with the FTDI-based >> >> >> > >> >> >> > convertors sold by Adafruit. Some good tutorials on that site >> too. >> >> >> > >> >> >> > https://www.adafruit.com/product/284 >> >> >> > >> >> >> > On 4/5/19, Jeffrey Birt <[email protected]> wrote: >> >> >> >> FWIW, I have had very bad luck with Prolific USB<->Serial >> converters. >> >> >> The >> >> >> >> have failed to work 90% of the time when I have tried them (on >> >> >> >> multiple >> >> >> >> platforms, applications, etc.) >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> FDTI converters are much better, far, far fewer issues. >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> I’m not saying for certain that the Prolific adapter is your >> issue but >> >> >> if >> >> >> >> it >> >> >> >> were me, I would suspect it. >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> Jeff_Birt (Hey Birt!) >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> From: M100 <[email protected]> On Behalf Of >> Thomas >> >> >> >> Morehouse >> >> >> >> Sent: Friday, April 5, 2019 7:15 AM >> >> >> >> To: [email protected] >> >> >> >> Subject: Re: [M100] TeraTerm - still not communicating >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> John - sorry, but I'm a dolt. Unfortunately I have no idea what >> >> >> "looping >> >> >> >> back both sides" means. >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> Hitting a brick wall! >> >> >> >> >> >> >> >> TM >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> On Fri, Apr 5, 2019 at 8:08 AM John Gardner <[email protected] >> >> >> >> <mailto:[email protected]> > wrote: >> >> >> >> >> >> >> >> OK. sounds like you know what you're doing. >> >> >> >> >> >> >> >> Have you tried looping back both sides of the connection? >> >> >> >> >> >> >> >> On 4/5/19, John Gardner <[email protected] <mailto: >> [email protected]> > >> >> >> >> wrote: >> >> >> >>> On the Device Manager toolbar, click View & select "Show >> >> >> >>> >> >> >> >>> hidden devices". What do you see now? >> >> >> >>> >> >> >> >>> I'm not familiar with Prolific-based USB to Serial devices; >> >> >> >>> >> >> >> >>> do you have the requisite driver loaded? >> >> >> >>> >> >> >> >>> On 4/5/19, John Gardner <[email protected] <mailto: >> [email protected]> > >> >> >> >>> wrote: >> >> >> >>>> In W10, open the Control Panel, click on Device Manager, >> >> >> >>>> >> >> >> >>>> click Ports (COM & LPT) - COM1 is normally the default - Is >> >> >> >>>> >> >> >> >>>> that what you see? >> >> >> >>>> >> >> >> >>>> On 4/5/19, Thomas Morehouse <[email protected] >> >> >> >>>> <mailto:[email protected]> > wrote: >> >> >> >>>>> Gentlemen - >> >> >> >>>>> >> >> >> >>>>> I've got my 102 connected to my Win10 laptop. >> >> >> >>>>> >> >> >> >>>>> USB to serial cable, with null modem adapter. >> >> >> >>>>> >> >> >> >>>>> I've got Telcom STAT set to 57E1E. Then I choose TERM. >> >> >> >>>>> >> >> >> >>>>> I've got TeraTerm set to Com6/Prolific, with port set to 1200 >> bps, >> >> >> >>>>> 7E1, >> >> >> >>>>> xon/off. >> >> >> >>>>> >> >> >> >>>>> Still no comms either way. Characters typed on either device >> don't >> >> >> >>>>> appear >> >> >> >>>>> on the other device. >> >> >> >>>>> >> >> >> >>>>> I'm just guessing at how to use TeraTerm, as even in the help >> files >> >> >> >>>>> I >> >> >> >>>>> find >> >> >> >>>>> no "step by step" to connecting. In other words, what to do >> when. >> >> >> >>>>> >> >> >> >>>>> Advice from a TeraTerm user needed! >> >> >> >>>>> Thanks. >> >> >> >>>>> Tom M. >> >> >> >>>>> >> >> >> >>>> >> >> >> >>> >> >> >> >> >> >> >> >> >> >> >> > >> >> >> >> >> > >> >
