Using the EMR II keyboard
Posted: 05 May 2022, 19:22
This is my first post here. I picked up an unused IBM EMR II keyboard some time ago. I decided to finally give it a try. The shielded cable has thicker internal wiring and a D-sub connector on the end. While I was puzzling over how to build an adapter for this cable, it occurred to me that it might be possible to use an original XT cable with this keyboard's controller. In fact, it turns out that if you remove some of the magic epoxy/plaster/paper mache that shields the internal controller board, you discover a standard XT style internal keyboard connector. You can remove the shielded cable and then connect a standard XT cable to the controller. The XT cable functions fine when connected to the EMR controller.
A couple peculiarities:
My example, as noted on the Deskthority wiki page, has "Caps Lock located to the left of A, Ctrl located to the left of the spacebar, and Alt to the right of the spacebar." However, the scan codes generated by pressing these three keys do not correspond to what the key caps indicate, instead they are identical to what you would see if you pressed keys in these positions on a standard XT keyboard. So, if you press the key to the right of the spacebar you get Caps Lock, just as you would on a standard XT keyboard, even though that key on the EMR board has an "Alt" printed on it. Same thing for the Ctrl and Alt keys. In effect, the key caps for Ctrl, Alt and Caps Lock are all in the "wrong" place. (I assume that whatever system these keyboards were originally connected to was doing its own key reassignments for these 3 keys.) It is an easy problem to fix - if you see it as a problem - by moving the Alt key to the left of the spacebar, just as it is on a standard XT. However, you cannot just swap the Ctrl key into its original XT position because the EMR Ctrl key is too wide to fit to the left of A. I fixed this problem by swapping in a standard XT Ctrl key.
Also, the bracket key "}]" closest to Enter on the EMR keyboard is not slightly oversized as it is on a standard XT keyboard. That leaves a bit more space around that key on the EMR board - you can see more of the plate underneath than you can on a standard XT keyboard.
The D-sub connector on the EMR II cable has some identifying information printed on it. "Kern Eng. 50619." It turns out Kern Engineering is still in business. Their web page says their "components have been and are being used throughout the world to protect sophisticated electronic hardware and systems under the most adverse conditions against EMI/RFI and EMP."
Even though I've made it less likely to survive an EMP, it is great fun to give a keyboard manufactured in 1987 an inaugural voyage. The typing experience is fantastic and feels to me to be indistinguishable from that of a standard XT keyboard.
A couple peculiarities:
My example, as noted on the Deskthority wiki page, has "Caps Lock located to the left of A, Ctrl located to the left of the spacebar, and Alt to the right of the spacebar." However, the scan codes generated by pressing these three keys do not correspond to what the key caps indicate, instead they are identical to what you would see if you pressed keys in these positions on a standard XT keyboard. So, if you press the key to the right of the spacebar you get Caps Lock, just as you would on a standard XT keyboard, even though that key on the EMR board has an "Alt" printed on it. Same thing for the Ctrl and Alt keys. In effect, the key caps for Ctrl, Alt and Caps Lock are all in the "wrong" place. (I assume that whatever system these keyboards were originally connected to was doing its own key reassignments for these 3 keys.) It is an easy problem to fix - if you see it as a problem - by moving the Alt key to the left of the spacebar, just as it is on a standard XT. However, you cannot just swap the Ctrl key into its original XT position because the EMR Ctrl key is too wide to fit to the left of A. I fixed this problem by swapping in a standard XT Ctrl key.
Also, the bracket key "}]" closest to Enter on the EMR keyboard is not slightly oversized as it is on a standard XT keyboard. That leaves a bit more space around that key on the EMR board - you can see more of the plate underneath than you can on a standard XT keyboard.
The D-sub connector on the EMR II cable has some identifying information printed on it. "Kern Eng. 50619." It turns out Kern Engineering is still in business. Their web page says their "components have been and are being used throughout the world to protect sophisticated electronic hardware and systems under the most adverse conditions against EMI/RFI and EMP."
Even though I've made it less likely to survive an EMP, it is great fun to give a keyboard manufactured in 1987 an inaugural voyage. The typing experience is fantastic and feels to me to be indistinguishable from that of a standard XT keyboard.