Televideo PC Keyboard Pinout/Adapter

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Polecat

06 Nov 2017, 01:05

This is for the Televideo PC (vs. terminal) keyboards, Model 803, 1603, 1605, TPC-I, and TPC-II, possibly others. These keyboards use XT scan codes, but have a 6 pin modular connector and run on 12 volts (vs. 5). So a custom cable will allow them to work on an XT application once the internal 5 volt regulator is bypassed. Scan of my old writeup attached, sorry for my complete lack of artistic skills.

edit: 17 August 2019, please see corrected drawing below!
Attachments
TPCKBD.JPG
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Last edited by Polecat on 18 Aug 2019, 03:33, edited 1 time in total.

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OldIsNew

06 Nov 2017, 02:14

Thanks for posting! It seems so difficult in general to find this kind of info!

orihalcon

06 Nov 2017, 07:07

Could you post a picture of what a correctly bypassed voltage regulator looks like on the PCB? Thanks!

User avatar
Polecat

07 Nov 2017, 04:29

orihalcon wrote: Could you post a picture of what a correctly bypassed voltage regulator looks like on the PCB? Thanks!
Good suggestion, see attached. Sorry about the $3 camera. This is the TPC-II version, but the others are similar. The 7805/78M05 regulator has three pins. Left to right - input, ground, output. Input is 12 volts, output is 5 volts. Cutting loose the two pins and bridging the input and output on the board allows 5 volts to pass through, giving you a 5 volt XT-compatible keyboard. You can remove the regulator completely, but it's easier to reverse this way. I'd suggest labelling the board so it doesn't accidentally get plugged into a Televideo.
Attachments
DSCN0005.JPG
DSCN0005.JPG (823.89 KiB) Viewed 775 times

User avatar
Polecat

07 Nov 2017, 04:32

Scan codes from the Televideo TPC-II Technical Reference Manual.
Attachments
TPCSCAN1.JPG
TPCSCAN1.JPG (84.95 KiB) Viewed 773 times
TPCSCAN2.JPG
TPCSCAN2.JPG (125.09 KiB) Viewed 773 times

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OldIsNew

07 Nov 2017, 05:11

Thanks again! Once again very helpful info!

User avatar
Polecat

07 Nov 2017, 06:11

OldIsNew wrote:
Thanks for posting! It seems so difficult in general to find this kind of info!

Thanks again! Once again very helpful info!
Glad to be able to share. I spent a lot of time playing with the Televideo PCs back in the day, and they were an oddball even at the time. Televideo just about owned the terminal market in the CP/M days, but when "personal computers" took over things changed. The Televideo CP/M computers (8 bit/Z80 based - 802, 803, TPC-I, etc) and their corresponding MSDOS ones (16 bit/8088 - 1603, 1605, TPC-II, etc) were well made, but never very popular.

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OldIsNew

13 Nov 2017, 02:02

Well I have a TS 804 board, bypassed the VR and have triple checked the wiring but no luck with Soarer's. HID gives output of keyboard ID 00000, PC/XT but no response at all to key presses. I added pull-up resistors and went ahead and changed the electrolytic caps on the board but no change. Interestingly the piezo buzzer does work with every key press - just no HID output. Any thoughts? - should I be using something other than Soarer's?

User avatar
Polecat

13 Nov 2017, 05:53

OldIsNew wrote: Well I have a TS 804 board, bypassed the VR and have triple checked the wiring but no luck with Soarer's. HID gives output of keyboard ID 00000, PC/XT but no response at all to key presses. I added pull-up resistors and went ahead and changed the electrolytic caps on the board but no change. Interestingly the piezo buzzer does work with every key press - just no HID output. Any thoughts? - should I be using something other than Soarer's?
I've never played with a Soarer's Converter, but I just ordered one a couple days ago so I'll soon have one to play with. When I was playing with the Televideo stuff I had a generic XT clone which I ran the Televideo keyboards on (using the above cable) and a Televideo 1605 and TPC-II which I ran XT-compatible keyboards on (using the reverse of the above, with a 5 volt regulator inside the DIN shell). I still have a TPC-II portable (not currently working) and a couple Televideo keyboards, so I'll let you know if they work with a Soarer's once it arrives.

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OldIsNew

14 Nov 2017, 19:00

Polecat wrote: I've never played with a Soarer's Converter, but I just ordered one a couple days ago so I'll soon have one to play with... I still have a TPC-II portable (not currently working) and a couple Televideo keyboards, so I'll let you know if they work with a Soarer's once it arrives.
Thanks, it would be cool to get the board working with the original controller.

User avatar
Polecat

15 Nov 2017, 07:19

OldIsNew wrote:
Polecat wrote: I've never played with a Soarer's Converter, but I just ordered one a couple days ago so I'll soon have one to play with... I still have a TPC-II portable (not currently working) and a couple Televideo keyboards, so I'll let you know if they work with a Soarer's once it arrives.
Thanks, it would be cool to get the board working with the original controller.
The converter arrived, just need to dig out one of my old cables or make up a new one. Probably take me a few days; I'm swamped at work right now, but I'll update with the results ASAP.

ozzyrulesar

17 Aug 2019, 16:12

Hello!.
I've bought a Televideo TPC Senior 2 computer lately. And i'm adapting a XT keyboard for this machine. So i'm doing the inverse job, like adding a LM7805 to the circuit.
I see that you don't connect the "middle pin, 3" on the DIN. But that's seems to be the "DATA" on the IBM PC/XT specifications.

I'm still finishing the circuit, BTW...so i can't say that it's not working.


Thanks.

User avatar
Polecat

17 Aug 2019, 20:12

ozzyrulesar wrote:
17 Aug 2019, 16:12
Hello!.
I've bought a Televideo TPC Senior 2 computer lately. And i'm adapting a XT keyboard for this machine. So i'm doing the inverse job, like adding a LM7805 to the circuit.
I see that you don't connect the "middle pin, 3" on the DIN. But that's seems to be the "DATA" on the IBM PC/XT specifications.

I'm still finishing the circuit, BTW...so i can't say that it's not working.


Thanks.
Good catch, I mixed up pins 2 and 3 when I did that drawing. The middle pin should be pin 2 and the far left pin 3, and the middle pin should indeed be connected as the data line, not the far left. Sorry for the confusion!

An adapter using a 7805 will indeed work, at least on the TPC2 and the 1603/1605 models. I haven't seen a Senior 2, but hopefully it's the same. I built quite a few of those adapters back in the '90s, and they worked with most PC/XT and clone keyboards. I still have the TPC2 but it's not working at the moment, probably bad caps in the power supply or monitor board. And I have one or two of my old adapters here someplace.

User avatar
Polecat

18 Aug 2019, 03:32

Let's try this again. Took me 3 minutes to redo the drawing and 45 minutes to get the P1 that runs my ancient scanner to boot. Seems the cat has been back there unplugging cables again.

Again this adapter is to run the Televideo keyboard on an XT connection. You can run an XT keyboard on a Televideo PC by building a cable with a female DIN connector instead of a male. You'll need to use a 5 volt regulator in the adapter or inside the keyboard to drop from 12 to 5 volts. The Televideo keyboards used a 6 pin modular cable, with straight- through connections, so you just need to use a female DIN5 instead of a male on the other end.
Attachments
TELEKBD2.JPG
revised version
TELEKBD2.JPG (75.2 KiB) Viewed 211 times

User avatar
Polecat

19 Aug 2019, 06:35

I've been doing some reading online, and one reference says that the 803 keyboard (CP/M) is not compatible with the PC/XT compatible Televideos such as the 1603, 1605, and TPC2. So if that's indeed true the above won't apply to the 803. The 1603/1605 (big gray wedge) and TPC1 and TPC2 (beige and gray latching portable case) keyboards are electrically compatible with each other, and are compatible with PC/XT keyboards other than the voltage difference.

I have personally used XT keyboards on the 1605 and TPC2 using a reverse adapter with a 7805 voltage regulator inline. I built quite a few of those adapters back in the day, and even sold a few to a local dealer who sold and leased Televideo PCs. And I have also used TPC2 and 1605 keyboards on XT clone computers (with a cable adapter) after bypassing the internal regulator. The 803 info above came from a customer in a former life, not confirmed, so that may be bad info. The only Televideo PC I still own is a TPC2, and it's not currently working. I have two of the keyboards for it, one NIB, and also the Technical Manual that came with it, if that helps anyone. Here are a few links with more info on the Televideo PCs. Note that none of the early Televideo terminal keyboards are compatible with the Televideo PCs, which is not a surprise.

http://worldofvax.blogspot.com/2019/01/ ... art-i.html

http://worldofvax.blogspot.com/2019/01/ ... oards.html

http://worldofvax.blogspot.com/2019/01/ ... -pcxt.html

User avatar
Polecat

26 Aug 2019, 00:06

Doing some spring cleaning and quite by accident stumbled upon my old notes on the Televideo keyboards. Naturally the paper copies survived while the old digital versions are buried on some old PC that probably no longer works. Thank goodness I didn't fall for the "paperless office" propaganda! These notes cover both versions--Televideo computer with XT keyboard, and XT computer with Televideo keyboard. Both are from 1991 or thereabouts.
Attachments
TPCKB2.JPG
TPCKB2.JPG (77.37 KiB) Viewed 100 times
TPCKB.JPG
TPCKB.JPG (95.83 KiB) Viewed 100 times

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