6 Nov
2011
6 Nov
'11
1:37 p.m.
Chuck Guzis wrote:
Over at http://www.obdev.at/products/vusb/prjhid.html,
the AVR V-USB
project site, there are a number of nifty low-cost AVR projects for
various keyboard USB projects, including replacing the electronics of
a Model M with a custom board, [...]
Cool! I've got an IBM Model M part number 1389194, which is an APL
keyboard for a 3192 terminal, with a not-quite-AT interface. I've
wanted to modify it into a USB keyboard. Looks like Chris Lee has done
all the hard work for me.
The 31xx terminals implement a subset of the AT/PS2 protocol. They have
a different 5-pin full-size DIN connector with different wiring than the
AT, though they are electrically compatible so you can make a wiring
adapter. However, they only have scancode set 3, so they need a hacked
keyboard driver to work with normal PC software. They won't work with
any USB adapter I've found.
The main thing I don't like about the 31xx keyboard layout is that the
cursor pad is a cross rather than an inverted T. I'll solve that by
remapping to swap the center and down buttons.
The USB HID Usage Tables define IDs for function keys up to F24, but the
IBM 122-key keyboards have another 10 keys to the left of the main
keyboard. There are standard IDs for some of them, like CrSel, but I'm
not sure whether there's a standard mapping for others.