6 Nov
2011
6 Nov
'11
10:38 a.m.
On Nov 6, 2011, at 12:30 PM, Jules Richardson wrote:
AIUI it has to be active on a keyboard as old as the
majority of model M's, which know absolutely nothing of USB - it's the logic in
the (modern) keyboard which detects whether it's connected to a machine via USB or
PS/2 and adjusts accordingly, rather than hardware on the PC side.
That's exactly right. There's nothing wrong per se with the passive converters
(the ones that convert USB to PS/2, anyway), they're just not really
"converters". The problem you run into is that the cheaply-developed firmware
in the keyboards themselves doesn't make for a particularly good PS/2 keyboard. To
convert something that's actually PS/2 (or, more accurately, AT keyboard, since
that's all that's going over those PS/2 lines for a keyboard anyway) to USB, it
has to be something active since USB is considerably more complex than any older bus.
You wouldn't just plug an RS-232 console on an RJ45 jack into Ethernet and expect it
to work, either; they're fundamentally different communications systems.
- Dave