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Telex 278 - An IBM 3278 clone with SD Hall Effect switches

Posted: 09 Feb 2017, 18:15
by Engicoder
Here is another of Cindy's finds. Telex Terminal Communications offered a line of terminals that were software and hardware compatible with the IBM 3270 at a lower cost. This keyboard is a clone of the keyboard for the IBM 3278. It looks very similar but uses cheaper materials. The case is plastic and the switches are Micro Switch SD series Hall Effect switches.
It came to me with quite a bit of ancient masking tape residue. Thankfully, it cleaned up nicely with a soak with WD40 and quite a bit of elbow grease and a non-scratch 3M scrubbie pad (the blue ones).

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The bottom cover seems to be made out of a metal filled plastic. The cable is grounded to it. The upper cover is made from very thick plastic. The caps and switches are pretty decent for their age.

Higher resolution images can be found in the Wiki:
wiki/Telex_270_Keyboards#PN:-952003-222

Posted: 09 Feb 2017, 18:18
by lot_lizard
Great pics Engicoder... So interesting that a similar debris shield was used on non-beamspring switch. Do you have a picture of the caps removed with the rubber membrane still in place? Also... seeing the controller sit below the assembly (under the wrist rest) is definitely wild.

EDIT: Nevermind... just checked out the wiki pics
Spoiler:
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Posted: 09 Feb 2017, 18:21
by Engicoder
lot_lizard wrote: Great pics Engicoder... So interesting that a similar debris shield was used on non-beamspring switch. Do you have a picture of the caps removed with the rubber membrane still in place? Also... seeing the controller sit below the assembly (under the wrist rest) is definitely wild.
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Larger here: w/images/2/28/Telex-270-No-Cover-Front-Mat.JPG

Posted: 09 Feb 2017, 22:27
by seebart
Great work on the Telex 270 wiki page Engicoder! Take note people.

Posted: 10 Feb 2017, 12:54
by XMIT
So glad you got this one.

I was somewhat excited because since this is a 3270 terminal the protocol is well known and you'll be able to use it over USB with relatively minimal effort and presumably 1KRO. I recall a 3270 protocol converter that a fellow in the Internet built but, like the last time I searched, I'm having a hard time finding it again! Perhaps someone else knows where it might be hiding.

Posted: 10 Feb 2017, 13:10
by seebart
XMIT wrote: So glad you got this one.

I was somewhat excited because since this is a 3270 terminal the protocol is well known and you'll be able to use it over USB with relatively minimal effort and presumably 1KRO. I recall a 3270 protocol converter that a fellow in the Internet built but, like the last time I searched, I'm having a hard time finding it again! Perhaps someone else knows where it might be hiding.
You don't mean this do you?

workshop-f7/ibm-3278-keyboard-to-ps-2-i ... hilit=3270

http://www.ibmsystem3.nl/IBM3278/

Posted: 10 Feb 2017, 14:37
by Engicoder
Thanks! One way or another I will get this attached to a computer so that I can experience it fully and get that solenoid clicking. The converter you mentioned would get it up and running, but I may go the custom controller route by replacing the socketed 8049. Then again, so many projects! :)