Subject: keyboard translator

From: "David Troutman" <[email-masked]>
Date: Wed Apr 2 03:28:31 2003

Hello there,
Found your address through Google.
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 that can do the
translation?
regards,
David Troutman

---

From: [email-masked] (Tony Duell)
Date: Wed Apr 2 18:01:00 2003

> ps2 based KVM switch.  Do you know of any products that can do the

All I can tell you is that the LK201 interface uses different voltage 
levels to the PS/2 interface (The LK201 is essentially RS232 levels with 
a 12V supply, the PS/2 is TTL levels with a 5V supply), and a totally 
different protocol (the LK201 is 4800 buad async, the PS/2 is, IIRC, a 
synchronous interfacem, with clock and data lines). 

A translator between them is not going to be totally trivial therefore. 
It would certainly need a microcontroller at each end.

-tony

---

From: Ethan Dicks <[email-masked]>
Date: Wed Apr 2 19:31:00 2003

--- Tony Duell <[email-masked]> 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[?]
> 
> levels to the PS/2 interface... and a totally different protocol...
>

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.

-ethan

---

From: Gene Buckle <[email-masked]>
Date: Thu Apr 3 08:56:00 2003

> Sun sells one of the cheaper units (surprise, surprise), but it is,
I think you can get one from Raritan cheaper than that.

g.

---

From: Ethan Dicks <[email-masked]>
Date: Thu Apr 3 09:18:00 2003

> I think you can get one from Raritan cheaper than that.

We had a Raritan switch at a former employer (about 100 yards from
where I'm sitting now ;-)... a nice one - 4x32 (and they bought an
expansion box after I was gone) - about $10K with cables.  At the
time (c. 1999), the Raritan converter was $150.  We bought a Sun
box to stick my SPARC2 (that I later sold them) on the KVM as our
first "non-NT" host in the server room.

Perhaps Raritan has a new model or has lowered the price on their
old model, but at one time, Sun had the cheapest solution.

-ethan

---

From: Gene Buckle <[email-masked]>
Date: Thu Apr 3 09:53:01 2003

> old model, but at one time, Sun had the cheapest solution.

Ahh, ok.  Good to know I guess. :)

g.