Re: Using a KVM switch to connect 3 computers at once

On 11/16/2023 2:10 PM, micky wrote:
> Running two computers at once. 
> 
> It happened sort of by accident but now I'm runing my laptop and my
> desktop all the time.  And I have a spare computer I really should set
> up.  
> 
> To use just one mouse and one keyboard and switch them from PC to PC, I
> need a KVM switch, but it seems that those that supply more than 2
> computers all have HDMI outputs.   And maybe I should get HDMI just
> because it's newer than USB. But my laptop and desktop inputs are all
> USB.   I gather someone like me is supposed to get an HDMI to USB cable,
> but that seems to connect only the mouse OR the keyboard, not both?   So
> what am I to do? 
> 
> I don't want to use only one monitor. It's good to be able to look at
> both so easily .
> 

There are the following graphics converters.
This is not an exhaustive list. I own three out of this
set, and multiple of some of them. Having multiple even
came in handy (accidental foresight).

HDMI to VGA (active, cheap)
DP   to VGA (active, cheap)

DP++ to HDMI (passive, cheap)
DP   to HDMi (active, cheap)   [For the Optiplex 780, which isn't DP++ capable]

DVI to HDMI  (could be passive)
DL-DVI to HDMI (active, likely $$)
(Anything DVI-I or DVI-D is pretty obscure now. Modern vid cards no longer have DVI-I.)

There are converters for just about anything. But you must
acquire a set, before they go out of production. The last
HDMI to VGA I bought, I had to go upmarket a bit and get
one with an analog audio output (stereo), in order to get
an adapter. Startech was almost wiped out by COVID. And
my local computer store, just doesn't have the stock any more.

Conversion at high resolution, can have more issues. I don't
have any 4K stuff here to experiment with.

*******

I would run a KVM on two computers, and leave the third
computer separate. I refuse to believe the three machines
need "equal access". For example, one machine here functions
as a NAS, and it hardly needs a screen when it is doing that.
I could sit that in the kitchen, and hardly ever look at it.

I could see if one machine was running Linux, another Windows,
the third machine was your file server, you might use a dual-port
KVM. KVM pricing is not "rational", and you will pay too much
in any case.

Switching could be done with a button or knob on top of the KVM.
Intercepting key presses is for the birds. Not all computers
seem to be compatible, and you have to be a Level 39 Wizard
to solve all the KVM problems. KVM setup is hardly ever a
joyful experience. It's expensive, and craptastic.

That's why the answer you got, with a monitor having three
HDMI inputs, that exemplifies the "easy" part of the problem,
the routing of graphics to a monitor. But some of the other
conversions (PS/2 interfaces to USB outputs or something),
that stuff can be pretty rough.

I don't own a KVM here. And I don't plan on fattening any
KVM company profits either. I have two monitors, two keyboards,
two mice here. For two machines. I put a PC in the kitchen
if I need a third.

   Paul