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Vintage Computers Any vintage computer systems, calculators, video games etc., but with an emphasis on 1980s and earlier equipment.

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Old 16th Apr 2019, 9:28 am   #1
__i4cy__
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Default Mystery Keyboard

I acquired this UK made vintage computer keyboard at one of the rallies last year. I was told by the seller that its provenance lies with the GPO.

Does anyone recognise this keyboard, if so do you know what computer equipment it was used with?

It has a 5-pin din which indicates it could be used with an original IBM PC. However being built in the 70s it predates the IBM PC, and the DIN plug pin-out is completely different.

The keyboard uses the General Instruments AY-5-2376 keyboard encoder IC. Requires +5V and -12V supplies, and outputs a serial ASCII like data stream. The PCB is marked CS20036/04, tested 8/2/79 by JM.

Any info, no matter how trivial would be much appreciated. Thanks.
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Old 16th Apr 2019, 12:54 pm   #2
SiriusHardware
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Default Re: Mystery Keyboard

Are you certain it's UK made? The reason I ask is that it has a USA-like key layout, with '#' on the '3' key rather than '', as would be found on a UK keyboard.
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Old 16th Apr 2019, 2:00 pm   #3
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Default Re: Mystery Keyboard

My guess is it's part of a minicomputer terminal. Not all manufacturers supplied a keycap to replace the # one, and some terminals couldn't even display 0x23 as on the screen. This was much less important in the 70s than it would become later, as most terminals were used in scientific and higher education environments. Commercial systems for applications like accounts and payroll were usually supplied with highly nonstandard tailored keyboards.
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Old 16th Apr 2019, 2:20 pm   #4
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Default Re: Mystery Keyboard

Yes it does look very like a mini/mainframe-computer terminal.

[BTW a version of the DIN-plug, with a screw-down retaining barrel, was used for the keyboard-connection on some IBM 3270-series terminals: see here: https://www.seasip.info/VintagePC/ibm_6110344.html ]
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Old 16th Apr 2019, 9:49 pm   #5
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Default Re: Mystery Keyboard

My first thought was that it belongs to something like a DEC VT100, alas it does not quite match any of the VT100 photos I could find online. It is certainly not IBM, the colours and construction are wrong.

Mike
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Old 17th Apr 2019, 8:32 am   #6
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Default Re: Mystery Keyboard

I've never seen an exact match to that keyboard; but the rub_out, LF, CR, repeat, break combination of keys on the right hand side, with control, shift and escape on the left is reminiscent of the teletype derived keyboards that were used on early minis (for example look at the the ASR-33 type of key layout that were used with some PDP-8s - very similar minus the here_is key).

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Old 17th Apr 2019, 8:39 am   #7
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Default Re: Mystery Keyboard

Quote:
Originally Posted by __i4cy__ View Post
its provenance lies with the GPO.
Looks similar to the "dumb terminal" type keyboards associated with the original System X exchange fitted in Woodbridge during the development period. The terminals I think where "Beehive"
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Old 17th Apr 2019, 10:36 am   #8
JohnBHanson
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Default Re: Mystery Keyboard

Early keyboards were arranged so that shift changed the ASCII output from numbers (0x30-x3f) to (0x20-0x2f) and letters from (0x60-0x7f) to (0x40-0x5f). This is simple logic
to change bit 5/4 when the shift key is pressed thus saving space in the decode matrix.

This keyboard looks to be that type. It should be noted that although the matrix in a teletype keyboard was slots in metal the same trick was used to change (0x30-0x3f) to (0x20-0x2f) for the shift key (teletypes did not support upper case.

Latter keyboards had shifted9=( etc

Last edited by JohnBHanson; 17th Apr 2019 at 10:38 am. Reason: tweek missing characters
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Old 19th Apr 2019, 9:07 am   #9
__i4cy__
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Default Re: Mystery Keyboard

Quote:
Originally Posted by SiriusHardware View Post
Are you certain it's UK made?
It has those familiar RS type "TESTED" stickers which I have never seen on American equipment. One of the stickers is dated 21/03/79 which leads me to believe it is certainly European. Also some of the TI 74LS chips are marked UK.

Quote:
Originally Posted by Dual Standard View Post
version of the DIN-plug, with a screw-down retaining barrel, was used for the keyboard-connection on some IBM 3270-series terminals
The 5-pin DIN (240) pin-out is the same, except here the shield pin serves to supply the -12v supply.

Quote:
Originally Posted by davidw View Post
Looks similar to the "dumb terminal" type keyboards associated with the original System X exchange fitted in Woodbridge during the development period.
The chap I bought it from did mention it came from the GPO, although a production environment not a development one.

Last edited by __i4cy__; 19th Apr 2019 at 9:24 am.
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Old 19th Apr 2019, 9:36 am   #10
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Default Re: Mystery Keyboard

Is there any part numbers on the PCB?

Cheers Mike T
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Old 19th Apr 2019, 10:15 am   #11
__i4cy__
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Default Re: Mystery Keyboard

Quote:
Originally Posted by Cobaltblue View Post
Is there any part numbers on the PCB?
Just "CS 20036/04 ISSUE 2".
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Old 19th Apr 2019, 4:01 pm   #12
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Default Re: Mystery Keyboard

(been a long time) but it shouts Apricot to me.
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Old 4th May 2019, 11:31 am   #13
__i4cy__
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Default Re: Mystery Keyboard

UPDATE

I have successfully designed an "adapter" (firmware and hardware) which allows this vintage keyboard to be used with any computer/tablet/phone housed with a USB port. The adapter uses a single PIC to convert the keyboard clock/data signals to to something understood by USB, and to generate the additional -12v supply.

Incidentally, this post was typed using it!
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Old 4th May 2019, 2:50 pm   #14
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Default Re: Mystery Keyboard

Nice!
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