IBM Model M OS/2 Screen Reader Keypad - Model M... or what?

[snuci]

Some of you may have seen an IBM OS/2 screen reader keypad on eBay recently at a pretty high price. Well, I couldn't let it go and worked out a price for it that was reasonable given that shipping was included and there were no duties. Below are some pictures of the IBM screen reader keypad. Yes, there are two key caps missing and I'm not sure if I can ever find them or have them reproduced. If anyone knows, please send me a PM. There is a "D" and a "#" missing.

You will notice the back label is marked "Model M" but it sure looks like a Model F to me. I could tell by opening it up but I've done that before with other Model F's and it is not easy to get the back panel back in place sometimes so I will leave it as is. It does have a couple of classic Model F construction features. For one, the barrels are removable. You can see by the absent top level of keys that they have a stop in them as well so that the barrels won't spin. Also, the back plate is solid and slides into place like a Model F as opposed to the plastic rivets normally seen on Model Ms. However, there is a plastic membrane as opposed to a capacitive plate as seen through the absent keys as well. Am I correct in believing this is a hybrid Model M/F?

I added the SDL cable from a Model M keyboard but I forgot my PS/2 to USB converter at work. I'll have to try it out tomorrow and see if it works as normal with the keys being displayed as marked.

Here are some pics:

IBM Screen Reader Pad - no rear cable

IBM Screen Reader Pad - no rear cable.JPG (279.31 KiB) Viewed 4142 times

IBM Screen Reader Pad - back

IBM Screen Reader Pad - back.JPG (342.4 KiB) Viewed 4142 times

IBM Screen Reader Pad - key caps removed

IBM Screen Reader Pad - key caps removed.JPG (369.72 KiB) Viewed 4142 times

IBM Screen Reader Pad - complete key pad

IBM Screen Reader Pad - complete key pad.JPG (409.44 KiB) Viewed 4142 times

IBM Screen Reader Pad - SDL cable plugged in

IBM Screen Reader Pad - SDL cable plugged in.JPG (372.99 KiB) Viewed 4142 times

IBM Screen Reader Pad - side profile with stand

IBM Screen Reader Pad - side profile with stand.JPG (334.52 KiB) Viewed 4142 times

IBM Screen Reader Pad - membrane exposed through absent keys

IBM Screen Reader Pad - membrane exposed through absent keys.JPG (385.53 KiB) Viewed 4142 times

IBM Screen Reader Pad - PCB board ICs marked late 1987

IBM Screen Reader Pad - PCB board ICs marked late 1987.JPG (363.22 KiB) Viewed 4142 times

IBM Screen Reader Pad - back plate identification label

IBM Screen Reader Pad - back plate identification label.JPG (370.73 KiB) Viewed 4142 times

IBM Screen Reader Pad - next to normal Model M for size comparison

IBM Screen Reader Pad - next to normal Model M.JPG (369.27 KiB) Viewed 4142 times

[seebart]

You will notice the back label is marked "Model M" but it sure looks like a Model F to me. I could tell by opening it up but I've done that before with other Model F's and it is not easy to get the back panel back in place sometimes so I will leave it as is. It does have a couple of classic Model F construction features. For one, the barrels are removable. You can see by the absent top level of keys that they have a stop in them as well so that the barrels won't spin. Also, the back plate is solid and slides into place like a Model F as opposed to the plastic rivets normally seen on Model Ms. However, there is a plastic membrane as opposed to a capacitive plate as seen through the absent keys as well. Am I correct in believing this is a hybrid Model M/F?

Very interesting. I don't believe I've ever seen a "hybrid Model M/F". What does it feel and sound like, more like an F or an M?

[emdude]

Pretty fascinating, I imagine that it would sound more or less like a Model M, if it uses Model M flippers, which appears to be the case.

I find the Model F style foam padding in lieu of a rubber mat particularly interesting though; I suppose that would affect the sound somewhat.

[snuci]

I'm at a bit of a loss. It actually feels more "snappy" like a Model F as opposed to the Model M keyboard next to it in the last picture. I tried to look at the paddles on the keypad through the barrels and at one point, I thought they were black (like the Model Fs I've taken apart) but they are not. I'm not exactly sure if black denotes a Model F paddle but these appear to be an off-white/clear colour, I think. These key switches are definitely stiffer and the keypad has a Model F sound.

[emdude]

Model F flippers have a different hinge construction from Model M flippers, here's two comparison photos:

A Model F flipper..

Spoiler:

vs. a Model M flipper

Spoiler:

Based on your photos I am fairly certain that it uses the latter kind of flipper/paddle. Also, IIRC, Model F flippers will not work with Model M membranes. Perhaps the difference in sound is due to the missing rubber mat which I imagine would otherwise dampen the sound.

Edit: Based on this post, removing the rubber mat from a Model M does make it louder and brings the sound close, but not quite, to that of a Model F, apparently..

[snuci]

Turns out you are correct about the paddles, emdude. I couldn't take the suspense and opened it up...

IBM Screen Reader Pad - odd mix of Model F plates and Model M paddles and membrane

IBM Screen Reader Pad - odd mix of Model F plates and Model M paddles and membrane.JPG (347.55 KiB) Viewed 4070 times

The sound, however, is much crisper, the feel is heavier. I think I use the word "crisper" because there is no rattle or reverberation when the sporing buckles; probably because of the foam sound deadening. If you think about it, the use of this was as a screen reader for the blind. Avoiding added noise would be pretty important. Maybe that explains the construction? This is just a total guess.

[Chyros]

Very interesting indeed, definitely a hydrid of the two. It looks badass, too!

[emdude]

I am not sure either, but I feel that the rubber mat and foam padding would both serve similar purposes, to keep out debris and/or to deaden the sound of the springs, etc.

I am rather curious about the origin of this frankenboard. I wonder if IBM decided it was cost-prohibitive to create a new mold for this niche keypad, and instead used an old Model F mold.. Was there ever a Model F keypad that looked like this? The closest board I can think of is the 50-key 4704.

[0100010]

More info about it here : https://geekhack.org/index.php?topic=43505.0;nowap

Please do not contact Jim Thatcher though.

[snuci]

More info about it here : https://geekhack.org/index.php?topic=43505.0;nowap

Please do not contact Jim Thatcher though.

Thanks for the link! I actually read this thread when I first saw it but didn't realize there were pictures in it. I think I got distracted at some point and started looking for the OS/2 screen software and found it at IBM's FTP site. I suspected it would have different scan codes or any keyboard would have worked with the screen reader software and they wouldn't need to sell a keypad. Back in the early 90's it would have been big money for the kit that included this keypad.

To get the software to work, I need an OS/2 machine up and running. We'll see what I can do but it won't be soon. I have a few other projects on the go.

I'm surprised people say it's more like a model M in feel. The Model M in the picture is softer. Maybe it had a few more miles on it, hence the difference in feel? I did try an IBM AT Model F and it was pretty close.

[andrewjoy]

Another example of the proto M. Membrane with model F style plate. very cool.

[Parak]

This style of construction has actually been known about for a while, for example here:

photos-f62/ibm-1392560-t8625.html

I vaguely recall a 50 key with the same on clickykeyboards website having also some rather colorful legends.

[andrewjoy]

I wonder if you could put a custom F PCB and F flippers into it and turn it into a real model F

[Ratfink]

I wonder if you could put a custom F PCB and F flippers into it and turn it into a real model F

I see no reason why you couldn't. We've turned things further from a model F into a model F.