Raritan makes them. (http://www.raritan.com) They're called the Guardian.
We use them on all of our customer's co-located servers (the customer pays
for them) so they don't have to bring keyboards and mice, and it allows us
to hot-plug a keyboard and mouse into them when need be. They support AT
and PS2 mice and keyboards and they can do an AT to PS2 conversion. They
run around $80.
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