RodSmallwood at mail.ediconsulting.co.uk
Sat Mar 17 07:32:58 CDT 2007
I think the keyboards were made up by putting keyswitches into a metal
plate then wiring them up in row and column form. A ttl system scanned
the rows and columns until it found a closed switch. The count was then
equal to the value of the character.
From: cctech-bounces at classiccmp.org
[mailto:cctech-bounces at classiccmp.org] On Behalf Of Tony Duell
Sent: 16 March 2007 23:22
To: cctalk at classiccmp.org
Subject: Re: old terminals...
> Old terminals
> In the UK in the early 1970's I worked for a (then small) UK
> called Newbury Labs.
FWIW, Newbury terminals were common at Cambridge University in the 1980s
(but were being replaced by BBC micros running a terminal emoulator). I
think they were around at other UK universities too.
> We made VDU's or video terminals. The early types used eight bit
> parallel shift registers as screen memory.
> The model number was 2480 i.e. 24 Rows of 80 Characters. They came in
> steel enclosures (painted blue!!) The screen was a 12" tube as used in
> mono portable TV's.
When I needed a replacement CRT for a Volker-Craig terminal (it has an
APL cahracter set, which is why I was repairing it), the only way to get
one was to buy a cheap protable TV and remove the CRT from it. Nobody
stocked the CRT on its own.
> We used to spend half an hour on each one fixing up the screen
> geometry with small magnets.
> The newer ones used a crude stored program system made out of TTL ie
> no Microprocessors.
I have a Newbury terminal somwehre. I forget the model, but it's a later
one with a separate keyboard linked up by a wide ribbon cable (I think
the connections are just the row and column lines of a switch matrix,
there's not much, if any, electronics in the keyboard).
I've not been inside it for 20 years, but I thought there was a
microproceossor in there. I do rememeber a board of TTL incluing some
'181 ALUs, though.
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