24 Apr
2019
24 Apr
'19
9:02 p.m.
On Wed, Apr 24, 2019 at 8:51 PM Al Kossow via cctalk <cctalk at classiccmp.org>
wrote:
The 924 should be the same as a 955 keyboard. There seemed to be two
compatible types of the keyboard - an older thicker keyboard (shipped the
TS-803 et al, and looks like an enhanced 925/950 keyboard), and a newer
thinner profile keyboard used on later terminals.
>>> The keyboard controller is an 8049.
Firmware not readable.
It may actually be compatible with the 955 keyboard, which I was able to
read.
Key layout is the same, though the manuf is different
From what I've figured out, the 955 uses a 6-pin
connector at 9600 baud
with both Tx and Rx used, and a reset line and +12V power.
The 925/950 use
a 4-pin connector, replaces the Tx to keyboard line with a speaker
connection, drops the reset line, and runs at 1200 baud as compared to the
955 keyboard. The keyboard should be the same between the 905, 955, 970,
TS-803, and some others with the possible difference of some legends on
keycaps. The TS-802, 800A, 925, and 950 use the same keyboard +/- some
legends.
Later terminals like the 965 use a 4-pin connector with a different pinout,
and +5V supply instead of +12V, but still at 9600 baud with the same codes
as the 970/etc.
I believe that the transmitted codes are the same for all of them, but the
older 925/950 keyboard is missing some keys than the later 970/955/etc have.
The TPC-I, TPC-II, TS-1605 all use a PC/XT-like keyboard interface, but
with a +12V power supply instead of +5V. I haven't quite verified if one
can swap them with XT keyboards with an alternate power supply yet, but it
may be possible. It seems like they should be compatible since the
TS-1605/TPC-II are fairly compatible with PC/XTs.
Pat