[geeks] Odd KVM question

[Jonathan Patschke]

On Tue, 19 Feb 2019, Fred wrote:

> I'd like to share just the LCD between the two terminals without having to
> swap the actual VGA cable.
>
> I've always been taught/told that those old school beige A/B
> "ker-chunkers" violate the laws of nature and will blow your equipment up.

For low-resolution analog video, they're fine.  Many of the horror stories
from those boxes come from using them to switch parallel printers (whose
buses can carry appreciable power when driven by old hardware) or PC
keyboards (whose buses just don't want to switch that way).  Switch bounce
didn't help the situation any.

At $job[-1] we had an in-house KVM design consisting of a bunch of FETs to
switch VGA.  The output was crap, but it was only used to monitor devices
under test, so that was okay.  Nothing blew up, even at thousands of
display-switches per day.

If you're still nervous, get a three-way switch, and leave the position in
the middle open so you can quiesce the data lines mid-switch. :)

-- 
Jonathan Patschke
Austin, TX
USA