10 Jul
2014
10 Jul
'14
4:29 p.m.
On 2014-07-10 3:00 PM, Philip Belben wrote:
And don't forget the RS/6000 keyboard. The 7012 could exchange mice
with the PS/2 (the RS/6000 mouse showed as "Logitech" under Windows),
but not keyboard. They looked very, very similar, but the protocols
the machines used to talk to them were very different. I found out
the hard way after an office move... The RS/6000 keyboard works well on a PC but
the PC keyboard will not
work on a RS/6000, after a bunch of the RS/6000 developers, who all also
had a PS/2 in their office, where relocated we got a lot of calls for
keyboards that did not work. The easiest way to tell them apart was the
RS/6000 keyboard had a speaker on the underside below the LEDs, in fact
now that I look I am typing on a RS/6000 keyboard.
The XT version of
the model M does not have any LEDs on it.
The model M was available with several different
connectors. Most
of the
I know of 2 (5 pin 'type A' DIN, 6 pin mini-DIN). What others are there?
> original AT (5170) had a 5 pin DIN connector that looked the same as
> the
> 5150/5160 keyboard connector, but they are elctrically very different. Actually, I seme to recall tht the signals are
the same -- clock, data,
+5V, ground. And on the same pins on both the XT and AT. The 5th pin,
origianlly a reset outptu from the PC to reset the keybaord at power-on
was, AFAIK, never used.
Hwoever, the serial protocol is very different betwee nthe XT and AT
keybaords. So while the clock and data are on the same pins, they
keyboards are not compatible.
The AT keyboard had LEDs for num/caps/scroll lock from the first. I
don't think there was anything in the 5150 keyboard protocol to handle
them, so they would have had to do something different anyway.
Philip.
Paul.