Texas Instruments 928 Terminal with 931 Support ROM

[+FarmerPotato]

@NybblesAndBytes brought me an interesting piece of equipment at VCFSW. 

 

It is a Texas Instruments Terminal, the CRT only, with an upgrade from Model 928 to Model 931.

 

There's a little plug-in module behind a door.  The board provides a 27PC512 OTP EPROM DIP28, and perhaps a GAL22V10 DIP24. 

 

 

 

The board seems to accommodate a DIP32 and has 2x3 jumper block. (Unpopulated) 

 

My guess is that the PLD is a bank switch? This is a 64KiB EPROM and probably is used in banks.  The board might be made for even bigger EPROMs, possibly with a version selected by jumper.

 

 

About the 931

 

To me, the CRT resembles a TI PC monitor ca 1983, but I read it was manufactured by HP.  It does VT100/VT220/VT320. Here is one random internet page.  

 

Bitsavers has the Model 931 Terminal General Description (1983)  under Terminals.  

 

Last week I explored boxes of TI manuals in the archive at DeGolyer library (SMU Dallas, TX).   I didn't discover any new 931 documentation.  Accession 94-8 is about half of the minicomputer/terminal data manuals. (980, 990, DX10, DNOS, etc)

 

The accession 94-8 covered 1970-1982.  Manuals for terminals are maybe 8% of the accession, with 50% being 990 book.

What I did see covered 733 ASR, 700/740/741/747, 743 KSR, 820 KSR, 911, 915.  

The 915 Field Maintenance manual is there but not the Depot repair manual. Bitsavers has those for 911.  

 

So no repair manuals for 928 or 931.

 

 

 

 

 

Edited July 31 by FarmerPotato
Renamed topic

[jbdigriz]

Oops, I missed this earlier.

 

If we can get a dump without tripping any anti-RE self-destruct, that'll be great, A dump of the stock 928 ROM would be nice also. Not sure if that's already online. 

 

TI and HP both bought similar terminals from a third-party, Taiwanese or Korean, don't recall which mfr. I'll have to go back and check my notes on all this.  I *think* the HP 700/60 and 700/92 have basically the same logic board as the 928, the difference being different ROMS, and they have 25-pin and 9-pin serial ports, iirc, instead of the 6p6c MMJ ports on the terminal both TI and HP sold as the 928. Pretty sure the HP 928 is just a rebadging of the TI terminal. Should be a NEC V20 and the same video chip in all 3 terms, anyway. Found a chart somewhere, have to dig it back out.

 

I'm trying to pin down anyone connected with HCS who might know the status of any IP and/or the whereabouts of any documentation, schematics, source code, etc. Also, HCS serviced TI computers back in the day, and made and sold a number of 3rd-party products for 990s, terminals, etc. 8-channel comm boards, memory, cache controllers, and so on. Info on those would be greatly appreciated. If anyone has a contact, please PM. I have a possible contact in mind, but that is subject to confirmation.

 

jbdigriz

[jbdigriz]

Don't worry, we'll come up with those maintenance manuals yet, @FarmerPotato. Thanks for making that trip to the archive, too, and a big shout out to @NybblesAndBytes for the all the help!

Edited July 8 by jbdigriz

[jbdigriz]

Found it! Trifold instruction card for the 928 to 931 conversion kit. I can snail mail the physical copy if you want it to keep with the term.

HCS_928to931_rotated_ocr.pdf

 

Any luck finding a keyboard?

Edited July 8 by jbdigriz

[jbdigriz]

I'm thinking it's probably better to say the kit lets the 928 emulate a 931, which is an entirely different beast.

 

[+FarmerPotato]

I got the HP 928 keyboard from biff_howard_tannen.  Power on!  

 

Unfortunately, the power button was jammed and apparently broken.  I have to hold it in.  The slide controls for contrast/brightness were also frozen, but wiggled loose.  I guess mechanical parts have oxidized.

 

It makes two beeps and goes to on-line mode.  

 

 

The Setup key brings up:

 

 

 

The rear ports:

 

 

From left to right. Arrows indicate markings on the terminal:

 

KEYBD    Modular Jack 6P6C.   Fits the HP 928 keyboard.

 

+-COMM   DB25 Seen with an F-F adapter.

|

|  ->  (two way)

|  <-

+-PORT1   MMJ offset 6P6C, Left/Right Arrows Icon

 

   ->  (one way)

  PORT2   MMJ offset 6P6C, Printer Icon

 

A helpful message reads:  X-RAYS GENERATED IN THIS INSTRUMENT ARE SUFFICIENTLY SCREENED.

 

The Setup menus let me configure PORT1 and PORT2 up to 19200.

The default is 19200,7,O,1  The 924 manual says this is for a 990, always odd parity. 

 

According to the 931 manual:

 

The 931 had ports EIA, Internal, AUX (out) I guess corresponding to the 928 COMM, PORT1, PORT2.

 

The 931 Internal port is for a MMJ cord going to a  TI computer with controller interface CI402 or CI403.

 

The 931 COMM port is for modem.  It says to use a TI Model 451, or Bell 212A at 1200 baud.

The 931 has a fiber-optic port, for use with CI404 terminal controller interface card.

 

 

Cable for a 931 to CI403 is the ‭2303077-0001‬  DB-25 to 18-pin.

 

DB25 COMM port <-> 18-pin P1 on my 990/10A

or

DB25 COMM port <-> 18-pin port P3 of the CI403 terminal controller interface card in my FX990/12.

 

My CI403 would be described in manual ‭2263897-9701‬ if we had it.

 

 

 

 

 

Edited July 31 by FarmerPotato
Updated with better info

[jbdigriz]

-

am being told the power button failure is a common issue on these terminals. There may be replacements available, possibly upgraded, is my guess. Have to look around. I am told though that the 924"+" term is better in this regard. Not sure what the "+" signifies, but the stock 924 does have a 931 emulation mode, as I understand it.

 

Another thing I need to check is if the 2 MMJ ports allow connection to 2 different hosts at the same time, for 2 separate, simultaneous terminal sessions. I'm thinking this may be the case, but then again, maybe not.

 

Edited July 24 by jbdigriz

[+FarmerPotato]

On 7/24/2023 at 12:06 PM, jbdigriz said:

. the stock 924 does have a 931 emulation mode, as I understand it.

The 924 manual appendix makes it seem like it speaks the 931 escape codes. It mentions an ANSI compatible mode. 
 

 

On 7/24/2023 at 12:06 PM, jbdigriz said:

Another thing I need to check is if the 2 MMJ ports allow connection to 2 different hosts at the same time, for 2 separate, simultaneous terminal sessions. I'm thinking this may be the case, but then again, maybe not.

 

The 931 manual describes connecting to two hosts. 
 

Of the two "internal" or P6C6 or MMJ or RJ12 jacks, my 928 labels those with "two-way" and "printer" icons. The DB25 COMM would be the other session. Either session can be configured to log to printer. 

[+FarmerPotato]

Connectors to fit the terminal:

 

The serial and printer ports are  MMJ, offset clip. But they will snugly hold RJ14 with clip broken off. 
 

The keyboard has the clip centered. 
 

Neither type of socket fits the LEGO Mindstorms offset RJ-looking types-they are a bit taller. 
 

I spent $10 at my Altex Electronics store for two RJ14 cords, their DE9, and DB15 adapter kits. 

Edited July 31 by FarmerPotato
Corrected what fits

[jbdigriz]

So, 6P4C on the serial and printer ports? I need to find the manual(s). Glad that is sorted out anyway. 

 

I am told the "field procedure" commonly used in the case of the broken power button is to wedge it with a paper clip, thumbtack, or, I'm thnking, maybe a SIM card ejector, while holding the button in. Then turn the term on and off using a power strip. That will get you by, but if it were me, I'd want to replace the switch.

 

 

[jbdigriz]

6P4C (MMJ, keyed with offset) confirmed by the CK802/CK803 terminal concentrator manual http://www.bitsavers.org/pdf/ti/1500/2557938-001_Terminal_Concentrator_Installation_and_Operation_Jul90.pdf See specs in Table 1.4.

 

This manual also references 928 manuals we are interested in, as well as those for the 924 and the 955 PC clone workstation.

From Table 1.3:

 

928 VDT User's Guide: 2561031-0001

928 VDT Reference: 2561032-0001

 

Haven't found a reference yet to the maintenance manual(s).

 

 

 

Edited July 30 by jbdigriz

[jbdigriz]

This looks promising: http://www.bitsavers.org/pdf/ti/1500/2557939-0001_Terminal_Printer_Information_Aug90.pdf

 

No board details (trying to figure out which video processor the 928 uses. Guessing the same as the HP 700/60, but not the /92. Reasonably sure the CPU is a NEC V20.) Loads of useful info, though, including for the 931.

Edited July 30 by jbdigriz

[+FarmerPotato]

The Terminal/Printer Information manual does document all the configurations of cables for 924, 928, 931, 955. 
 

It gives the TI cable part number. Not pin wiring diagrams.
 

I'm going to infer the pin out from 924 and 931 manuals which have pin descriptions and TI cable part numbers. 

[+FarmerPotato]

Summary: Port 1 of the 928 is both the DB25 RS232 and the MMJ as RS422 (differential pairs.)

 

The RS232 looks to be standard DTE wiring. I want to connect the 928 to Geneve2020--currently using 9902 TTL out to FT232 adapter. 

Plan: make a DB25 DTE, test it with PC crossover cable. Then put a 9-pin port wired as DCE on  Geneve2020. Use a MAX3232 chip + 9902. Already got that laid out on PCB. 
 

The MMJ for port 1 is RS422 differential pairs. There are transceivers like TI's SN75ALS192/193 parts.

Another idea I like: also add the MMJ terminal jack to my main board. Since RJ12 cord and jack is so cheap, I'd forgo the MMJ offset. 
 

Edited August 24 by FarmerPotato
Add pic

[+FarmerPotato]

Lammert Bies: guide to interfacing MMJ DECNet:

https://www.lammertbies.nl/comm/cable/dec-mmj

 

Answers all of my questions. 

 

Matthew pointed out the HP User Manual on bitsavers.  HP 700/60 is the same terminal. 

http://www.bitsavers.org/pdf/hp/terminal/700/HP_700_60_C1080/C1080-90009_HP700_60_Users_Manual_199203.pdf

 

Edited August 5 by FarmerPotato

[jbdigriz]

Do we have pics of the 928 logic board yet? Still trying to find the 928 manual(s) here. Maybe I'll luck out and there'll be one in the box of TI docs I have on the way.

Edited August 6 by jbdigriz

[+FarmerPotato]

No, I didn't open it up: expected an assist for CRT  safety. But it's been turned off for 2 weeks and I have the serial cables...

 

Also I read the HP 700/60 manual, it looks perfect. 

[jbdigriz]

OK, the box of manuals I mentioned above came in, but nothing for the 928. Wasn't expected, but there was the off-chance. Have to keep looking. It is not in any of the indexes of the  DeGolyer material that I've seen, but there's plenty more that we don't have indexes for yet. So there is hope there for that. 

 

I did get duplicate copies of the 931 General Description and the 924 User's Gude, though. These have already been archived on bitsavers.org, but it's nice to have dead trees, and sometimes more convenient. I could Ebay these and recoup the shipping cost, but if anyone else in the 990/12 project, or anyone else here with a need, wants a physical copy of http://www.bitsavers.org/pdf/ti/terminal/crt/2229228-0001A_Model_931_Video_Display_Terminal_General_Description_Dec83.pdf or http://www.bitsavers.org/pdf/ti/terminal/crt/2544365-0001_Model_924_Video_Display_Terminal_Users_Guide_Jan87.pdf do please let me know and we will make arrangements to get these to you for the cost of shipping.

 

I'm also expecting a book scanner that does A3 pages to arrive tomorrow, so scans of the wide format material I have should be forthcoming. Yay!

 

 

Edited August 14 by jbdigriz

[brantcy]

Hello FarmerPotato & jbdigriz,

 

So, I've been following this thread for a week or so now, while doing my own, somewhat parallel, research into these terminals.  My interests however, stem from a keyboard that I recently acquired - a TI Low Profile Keyboard (p/n 2228995-001), which seems to have been used with the Model 931 VDT, as well as the S300A system, and possibly (probably) others from what I've read thus far.  I suppose we have different end goals in mind though, as I'm looking to use an MCU to do a (non-destructive, entirely reversible) conversion on this keyboard, adapting it to modern usage.

 

Anyway, all this to chime in and ask if there's a chance that either of you might know the pin-out for the keyboard ports used on TI terminals?  I've read the manuals that you've been discussing, (and scoured the internets for field and depot level manuals - to no avail) but I have to confess my ignorance at this point, none of the pin-outs I've found seem to be related to the keyboard port specifically.  I'd absolutely love to hear that I am mistaken though, or that one of you have stumbled across such information during the course of your project, and you both appear to be quite a good deal more knowledgeable regarding these terminals than I am.

 

Thanks,

-brantcy

 

Oh, sidebar - PotatoFarmer, I'd love to see a picture of that HP 928 keyboard you got from biff_howard_tannen.  I've also picked up a keyboard or two from that seller, but I'm mostly just curious to see interesting keyboards, it had not occurred to me that their might be cross compatibility.  I'm only 42, so terminal usage was before my computing awareness began unfortunately (or thankfully, lol.)

[brantcy]

Additional comment to upload a handful of documents I've run across that may be of some use.

Texas Instruments TMS 5001 NL preliminary specifications (1975).pdf 0945401_990-4Maint.pdf 2240275-9701B_Business_System_300A_Operators_Guide_Jul85.pdf 2243131-0001_ExplFieldMaint.pdf 2557938-001_Terminal_Concentrator_Installation_and_Operation_Jul90.pdf screengrab - possible KBD pin-out.bmp

[jbdigriz]

Hi, Brantcy,

 

Look, I'm not sure I can convey just how exasperating it is see people focusing so much interest in collecting JUST the keyboards, or, yes, ruining them, by converting them for use on a PC or whatever, non-reversibly, while perfectly good, increasingly scarce vintage terminals and computers get scrapped, or sit forlornly as static museum displays sans keyboard, like the 931 with the 990 system at RE-pc in Seattle, or the one currently on Ebay listed with a 911 keyboard, not the one from a 931. Then again, I don't understand a lot of things in the modern world, like how is sacrificing 5000+ acres of timberland to build an EV plant, plus all the follow on growth everyone slavers for, 4-laning more highways, expanding franchise suburbia another 50 square miles, etc., going to do all that much to mitigate climate disasters, actually? I don't see those numbers being run, just "how many billions can we milk out of this pretext?"

But I digress.

 

That said, if it's your keyboard, you can do with it what you want, and sometimes keyboards just get separated, for whatever reason, and I appreciate the screengrab, pdfs, and picture. I would like to plug https://bitsavers.org, where you can find those pdfs also, in the /pdf/ti directory.

 

Gotta run, get back to you later on your question.

[jbdigriz]

I am encouraged that you are planning a reversible mod, and I'm glad to see you seem to be developing some interest in the terminals and possibly the systems they were connected to. Ideally you would be able to complete a 931 term (which was used with BS300 systems; the BS300 system itself is built into a 940 terminal case as I understand it.) at some point. Not sure if the kbd is the same, don't think so, but maybe. Aah, too much to keep on the stack with everything else going on. I'll have to remember to look that up again. 🙂

 

As to your question about the keyboard connector pinout, I'm looking through the 931 manual right now. I only have the General Description, we're still looking for the maintenance manuals on the 931, I think.

 

Have fun,

jbdigriz

Edited August 22 by jbdigriz

[jbdigriz]

update: nothing in the Gen Desc. Have to keep looking.

[+FarmerPotato]

@brantcy

Welcome! It's encouraging to have another person on board the 931 train!

 

For the MMJ 928 keyboard I got from Howard, I'm guessing this is the pinout:

My Aug 5 post:

Quote

Lammert Bies: guide to interfacing MMJ DECNet:

https://www.lammertbies.nl/comm/cable/dec-mmj

 

I think you asked about the 931 terminal pinout  though? I'm on that quest. @arcadeshopper is also generously holding several 931s for me.  
 

I've some hope that the depot, and on-site manuals, are in the DeGolyer Library TI Archive at SMU. 
 

I have two group reference numbers from my 2021 visit.  The one I browsed in July 2023 was a group of 1000 manuals. Its index covers 1970-1980. I hope the second group covers the 80s when these terminals were supported.
 

Planning a multi-day trip to the library soon.   I can fill out a form to ask TI permission to "publish", I'll see where it goes. 
 

 

 

[brantcy]

Thanks you two!

 

    I actually work with/around/for a guy here in NM that has a 7k sq ft facility (and quite a few storage locations as well I gather) that are absolutely jammed to the ceilings with, all sorts of vintage tech, hundreds of terminals, systems, you name it.  He started collecting in the 80's and he asked me to help him parse and sell stuff for him.  I have learned a ton, and it's been awesome.  Initially yes, I met him while looking to get an older keyboard.  The modern one I had discontinued a replacement wrist rest after a single year.  They wanted me to buy their new and "improved" shiny rgb keyboard for $250.  Sometimes I can be a bit, rash, I guess, but i took offense and decided to build my own, and after some self educating, learned about the keyboards of my youth being far and away better than anything modern, and well, here I am.  I currently have 60ish? keyboards, including actually @FarmerPotato, a TI 924 VDT keyboard, although it's missing the "1" key from the numpad.  I'm not really aiming to come here and start "hawking(is that even the right word?) my wares", but I really haven't got a good use for it, not as good as you have anyway.

 

    Heck, I'd probably have dragged a few terminals home by now as well, but digging them out is gonna be a, task, to put it mildly.  Also, @jbdigriz the S300 does use the same keyboard as the 931, I forget where I found those manuals, but bitsavers is as likely as anywhere - although I did a 5-day hyper-focusing event (it's, something that i struggle with, but it comes in useful sometimes...) , and i've scoured the net, obscure websites, and lots more.  I've turned up lots of good information, but not yet what I was searching for.

 

    I actually ran into that SMU collection online, and it's awesome that you're able to access it!  I'd very much appreciate if you were to find anything useful!  We have a bit of a "library" of manuals and docs, but idk what's needed or isn't.  I can upload some pictures of the binders and manual spines, and you can perhaps tell me if anything might fill a gap in knowledge?  Aside from that, he's also got just boxes and boxes of manuals, but as with the terminals, it's kind of a scavenger hunt to find things in there.

 

 

    I'm 42, 7 credits away from an IT degree, and honestly, I don't even care anymore.  I want to follow this path.  I'm also a very disabled war vet, so I have some latitude to follow my own, path I guess.  I'm not about to gut any of these board to make some of the ridiculous things I've seen.  I want to use this keyboard, because it's a damned fine piece of work, and it deserves to be used.  If I can do so without damaging or destroying anything in it, then I will.  If not, I won't.  Last thing I'll say on it is that I have found my passion with vintage computing.

 

    Here's a picture or two of that keyboard I mentioned, for the 924, or 8?  I forget as much as I discover, infuriating!