keyboard translator

From: Ethan Dicks <>
Date: Wed Apr 2 19:31:00 2003

--- Tony Duell <> wrote:
Someone else asked:
> > We are trying to connect a Vax 3850 using a LK201 keyboard and
> > a ?mouse to ps2 based KVM switch. Do you know of any products[?]
> All I can tell you is that the LK201 interface uses different voltage
> levels to the PS/2 interface... and a totally different protocol...
> A translator between them is not going to be totally trivial therefore.
> It would certainly need a microcontroller at each end.

Sounds similar to hooking classic SPARC gear to a KVM. For _that_,
Sun sells one of the cheaper units (surprise, surprise), but it is,
IIRC, $75.

With sufficient magic, one microcontroller ought to be able to convert
PS/2 to LK201 protocol. The Atmel 90S2313 has an internal serial port
that should have no problem speaking to either the DEC keyboard or
the DEC mouse and has plenty of lines left over (and some sample
code on the 'net to speak PS/2-ees, if I'm not mistaken) to emulate a
PS/2 keyboard or mouse.

Given timing issues and that Atmel chips are $3 each, if I were rolling
my own, I'd seriously consider a dedicated microcontroller for each
device even though that would double the hardware cost (an expense I
think would be justified by simpler software design and more robust
operation). With sufficient horsepower, or a CPU with two hardware
serial ports, it might be feasible to do a two-fer.

I do not know of any off-the-shelf devices that can do this.

Received on Wed Apr 02 2003 - 19:31:00 BST

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