Continued from
http://geekhack.org/showthread.php?t=8513.
So, my Model F AT showed up. Not my first, but I lost mine some 15 years ago, which originally came to me complete with a PC/AT and an EGA screen as an IT castoff from the firm where my Dad was then working. It has been some time - but they were good times before, the hassle of cleaning Stoned off my machine and all the 5.25s - except for one which then reinfected me, BBSing with Qmodem, using a "borrowed" dialup shell account to a local university, irc, gopher, ftp, and later, for a while, lynx. Oh, and Borland's DOS IDEs.
I had totally forgotten about the layout "problems" that many people complain about now - frankly, they were never much of an issue for me as switching to the numpad is a deliberate act, so hitting the button seems much the same as modal changes in vi. Backspace and escape where just where and what they were - I had used too many computer layouts (Apples, IBM clones, and the occasional Sun) to care by then.
This ebay find ($56 shipped!) however, had an extra solution for that: a "Keypatch AT" (also described as a Keypatch 10 on the reverse side). In the ebay finds thread, speculation was that it was a rubber dome pad with a parallel interface. Neither is correct - and the keycaps were a suprise:


The interface is clean and simple actually. The Keypatch's straight cable is threaded down the center of the Model F's coils. It terminates in a female AT connector for the Model F and a male AT connector for the computer.
Now, I don't have an AT computer anymore, but my Core i7 does have a single PS/2 port which usually is home to the keyboard part of my M13. After some false starts with some sort of custom adapter that *looks* just like an AT/PS2 adapter (should have used the multimeter the first time I had problems, not 45 minutes in, ugh), I managed to find a local repair firm a few blocks away that would sell me one for $10. Yay.
I guessed that hotswapping wouldn't work, (and Win7 was not happy with me for trying) but even off a cold boot, there was nothing. Next I went to my crappy Belkin KVM switch, which is fine with hotswapping, but still, nothing. Finally, USB. I have a few adapters, both K+M and single PS/2, but the only one that worked was a piece I picked up from J&R a couple of weeks ago. I went there specifically to buy a Belkin one that came recommended, but I picked up a second one
because it was advertised as working with Apple and Sun as well, which, aside from covering my other computers, indicated to me that they designed this for people to do stupid things.
Only problem was, all the keypatch status lights were on - it wasn't functioning. The Model F, however, worked just fine. It occured to me that some older hardware was in order, so I pulled out the Airlink luggable. I disconnected the loopback PS/2 cable (Blue Cherry lid keyboard to case mounted RJ-11, to internal PS/2, which then pops out of the case through a hole near the ISA cards, where it plugs into a -suprise- ISA I/O card.
Shrug.) and plugged the F+Keypatch in. Lo, and behold:


Even more interesting:


Yeah, someone needs to tell me what these switches are [EDIT:Apparently, Cherry M84 linears]. In a word, they suck. They seem roughly linear, with a roughly MX like stem. Cherry caps interchange just fine, though the stem fins are not equal in horizontal and vertical length. There is a foam layer over the PCB which provides extra spring back. It just may be the worst keypress I have ever experienced - very heavy and very mushy.

More stupid switching:



Sorry if I went overboard with the pictures; I'm away from my apartment for the next few days, so I figured more is better cause I wont be able to add new shots to answer any questions.