23 Sep
2011
23 Sep
'11
7:06 p.m.
On 24 Sep 2011 at 2:20, Liam Proven wrote:
I have no clue about the signalling level stuff, but
there were also
PS/2 mice; same physical socket, different signalling. Mice wouldn't
work on keyboard ports and keyboards wouldn't work on mouse ports,
until the very end of the lifetime of the standard.
There were never AT-interface mice - so *something* in there is
different.
The lack of interchange betwen the mouse and keyboard is largely a
function of the microcontroller attached to the connectors. It was
not at all uncommon to see 90's "clone" PC keyboards and cases with
two punchouts in the connector area; a large one for the full-sized
DIN connector and a small one for the (PS/2-type) mouse. The
keyboard connector was downsized when the ATX cases and boards came
out.
But the "PS/2 mouse" didn't originate the use of the mini-DIN
connector. That belonged to the Microsoft bus mouse, aka the
"InPort" mouse in which the mouse was pretty much all passives and
the interface board had a dedicated microcontroller.
I've still got a pretty good pile of RS232 mice as well as a couple
of trackballs. Many versions of Windows are smart enough to detect
and configure the serial mouse, even if a PS/2 mouse is also
attached. Makes for some interesting two-handed pointing...
--Chuck