View Full Version : Cifer PS502 dumb terminal: Looking for info + posting what I've got.

March 19th, 2015, 02:12 PM

I picked up an old British mid-1970's serial terminal yesturday, for about 15$.

It's made by a company called Cifer, and bears model number PS502, and a very low serial nr. in the 300's.
Besides a single image, I can't find any documentation on it. So whatever I find out, I'll post here, and if anyone has any info at all on these, I'd really appreciate it.

It doesn't work, in its current state, after 30+ years on an attic, but the digital circuit boards seem in very good shape. It had a faulty PSU, now fixed,
but there's still an issue with the CRT. Can't get a picture. It is a "real" dumb terminal; apart from some CRT driver stuff, and some RAM, all chips are either 74- or 54-series logic.
Character gen. is done in PROM's.
The keyboard unit seems to have been delivered by another British company: Alphanumeric Keyboards Ltd.
Here is a (not great) picture of the assembled unit. Switch tops fell off during transport.


And the logic boards:

I really hope someone knows this machine; there is NO info on it out there.


March 19th, 2015, 03:02 PM
The only Cipher terminals I ever came across were Z80 based. This must be real early in their life....
... so sorry I have no info either.