On Wed, 15 Sep 2010 07:54:39 +0100, Lobster wrote:
Just make sure you get an "intelligent" one - it's hard to tell from a
lot of ads out there whether the thing for sale is just a dumb
convertor or not (and some folk will try to sell you a dumb convertor
claiming it'll work)

What does an intelligent one do? I have what I'm sure must be a 'dumb'
converter (99p off ebay) to use an old PS/2 keyboard with my laptop or
my son's Playstation, and it works fine?

With more modern (how modern I don't know, but I suspect anything after
the late 1990s) keyboards, the keyboard has the intelligence to work out
what kind of interface it's connected to (PS/2 or USB) on the main system
and switch to using the correct protocols and voltages. A 'dumb'
convertor is just an adapter between connection types and removes the
need to change cables; a modern keyboard with a PS/2 connector plugged
into a PS/2 port on the main system will run in "PS/2" mode, and if
plugged into a USB port on the main system (via a dumb convertor) will
switch to "USB mode"

Most (and maybe all) Model M's pre-date USB, so all they know is PS/2
voltages and protocols - hence the need for an intelligent convertor to
do the translation to USB; the convertor looks like an old PS/2 port to
the keyboard, and looks like a USB keyboard to the main system.

(I've no idea if ultra-modern keyboards with USB plugs at the end of
their cables lack PS/2 functionality - I've never tried that, and I'm not
sure if you can get intelligent USB-PS/2 convertors that work in the
"other direction")

cheers

Jules