Anyone familiar with these vintage touchscreens?

Nigel Johnson nw.johnson at
Sat Oct 19 13:23:46 CDT 2019

Judging by the year, it was probably a teletext terminal. There were 
various field trials of such systems around that era.  We had one in 
Toronto's Eaton Centre - it was based on NAPLPS, and used a PDP11/23.  
There was a lot of Canadian Government money put into research to 
promote he Canadian vector-based protocol, claimed to be more efficient 
than the European alpha-mosaic ones.  Ours ran at 1200/150(?) baud.

Research was done at a Bell Canada site on Carlingview Avenue in Ottawa 
under some sort of sub-contract.   They used Able DMAXes on an 11/70 
which had a pot to adjust the 150 baud clock.  They actually flew me up 
from Toronto, with a scope, to adjust that pot, since everybody there 
was hands-off this external stuff.

It may have had a future if HTTP and the internet were not just around 
the corner:-)

One of the big players in Canada was Infomart, where I installed a bunch 
of kit on PDP11s, just around the corner from where I now live in Toronto.



On 19/10/2019 14:02, Jonathan Katz via cctalk wrote:
> Hi!
> I saw this crop up on twitter and now I’m curious. Anyone familiar with
> these? Any idea what the backend was?

Nigel Johnson

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