RAFI DT-02

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seebart
Offtopicthority Instigator

13 Jun 2015, 18:50

this is a BTX decoder keyboard from RAFI. If you care to read about BTX here is a link:

https://en.wikipedia.org/wiki/Bildschirmtext

I got this keyboard boxed, if it was used then little. Looks like new.
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It comes with two manuals, a connector cable and a power supply.
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The case is very solid plastic all around. Being a BTX keyboard it has some unusual symbols on some keycaps. No yellowing anywhere.
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This keyboard has RAFI mechanical RS 76 M switches with orange sliders across the board except for caps lock. They feel very similair to the switches on the Compudent with the salmon sliders.
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The keycaps are low profile doubleshots like on the Compudent keyboard.
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Once again I fail to decrypt the RAFI codes on the PCB. But the manuals are dated 1987, so we have some indication.
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Low profile.
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Last edited by seebart on 14 Jun 2015, 10:37, edited 2 times in total.

User avatar
Chyros

13 Jun 2015, 21:26

Wow. What a board Oo . If it turns out it doesn't work, you can always use it as a table ;) .

Nice post!

The switches look a little bit like ITW Magnetic Valve switches, I think. Which I suspect are also Hall effect switches. Are these linear?

zts

13 Jun 2015, 22:30

Awesome find, seebart! Super clean ... looks like new. The times when people paid attention to detail ... including the printed manuals.

dzhoou

13 Jun 2015, 23:54

Isn't 76-C the hall effect one, and 76-M leaf spring?

User avatar
XMIT
[ XMIT ]

14 Jun 2015, 03:46

Chyros: magnetic valve and Hall effect are different things that look somewhat similar. The former uses magnetic position to either couple or not couple two wires inductively. The latter use a Hall effect sensor that generates a voltage that is proportional to magnetic field strength. These look like Hall effect to me. Magnetic valve always has a telltale tiny ferrite bead.

User avatar
Chyros

14 Jun 2015, 04:13

XMIT wrote: Chyros: magnetic valve and Hall effect are different things that look somewhat similar. The former uses magnetic position to either couple or not couple two wires inductively. The latter use a Hall effect sensor that generates a voltage that is proportional to magnetic field strength. These look like Hall effect to me. Magnetic valve always has a telltale tiny ferrite bead.
Cheers for the explanation, that makes a lot of sense! I'm sure those switches are actually RAFIs, it's just I couldn't help but notice how much they looked like ITWs :) . Both clever systems tbh. Guess neither of these would work very well in the Nuclear Magnetic Resonance department xD .

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XMIT
[ XMIT ]

14 Jun 2015, 04:16

Hmm. They *might* work. It all depends on the field strength. Inside an MRI, maybe not.

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OleVoip

14 Jun 2015, 10:13

Sorry to disappoint you, but (as with the compudent board) these are mechanical keys, not hall effect ones. In photo no.5 (key caps off) you can actually see the metal leafs and the noses of the sliders, which hold them up from their counter contacts. And in photo no.7 (backside of the pcb) you can see that every key has only got two pins. Hall effect keys, however, need extra pins for the power supply.

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seebart
Offtopicthority Instigator

14 Jun 2015, 10:36

No no OleVoip I want you to tell us. That's no disappointment at all. Thanks for letting me know. I corrected my post.

Small update; the caps lock switch has a white slider and is latching. More interesting is that while all keycaps are "scooped" the control keys are rounded. Interesting approach. Not sure if I've ever seen that. I hope you can see that in my picture.

Image

Image
Last edited by seebart on 14 Jun 2015, 14:45, edited 1 time in total.

User avatar
Chyros

14 Jun 2015, 12:36

XMIT wrote: Hmm. They *might* work. It all depends on the field strength.
9-14 Tesla.
More interesting is that while all keycaps are "scooped" the control keys are rounded.
Wait, I can't really see what you mean. I can see that most of the caps are concave but that the shift, F and ? keys are convex, is that what you mean...?

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seebart
Offtopicthority Instigator

14 Jun 2015, 12:45

Yes Chyros that's what I mean. I lack your scientific terminology. :D

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Chyros

14 Jun 2015, 13:16

Ah, I thought you meant the Ctrl keys specifically, but they're look like the other keys, hence the confusion xD .

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seebart
Offtopicthority Instigator

14 Jun 2015, 13:43

Spacebar, shift, function, return and backspace are convex. The rest are concave. Scientifically speaking. ;)
Chyros wrote: Wow. What a board Oo . If it turns out it doesn't work, you can always use it as a table ;) .

Nice post!

The switches look a little bit like ITW Magnetic Valve switches, I think. Which I suspect are also Hall effect switches. Are these linear?
Yes they are linear. Long travel. Very uniform in feel.

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