KVM mort


This isn’t a post about the KVM Hypervisor, which I believe is alive, well and rather good.

This is a post about keyboard, video and mouse switches.

‘KVM Switch Needed’
CC photo by Emily OS

At both home and work I have multiple machines, and monitors with multiple inputs, so all I need is a KM switch to share my keyboard and mouse rather than a KVM switch. Video switching was fine back in the days of VGA to analogue monitors, but these days it’s anachronistic (I want a digital input and though digital switches are available they’re expensive) and unnecessary (as any decent monitor has multiple [digital] inputs).

A better monitor

I could say that I want just a KM switch[1], but that might be asking for faster rewind for video tape in the age of DVD. What I really want is an integrated KM switch. Monitors already often have USB hubs that could reasonable be used for keyboard and mouse – it would be a small step (and very little silicon) to make that switchable to multiple USB outs[2].

Next up I want a means to switch between inputs that doesn’t involve pressing too many buttons. I don’t quite get why I have to go through a navigation exercise to switch inputs but it’s the same problem on my monitor at home, my monitor at work even the TV I have in my bedroom. Rather than a single button to cycle between (live) inputs I have to press something like input (or source) then go up/down a list then select an input – far too many button pushes. Of course if the monitor had a KM switch in then the monitor maker could take a hint from the KVM people and have hot keys (on the keyboard) to switch between inputs[3].


As I’m not in the market for a new monitor a cheap and functional KM switch would be ideal, but this stuff really should be built into the monitor to improve upon USB hub functionality already there[4].

[1] Yes, I know that I can use a KVM switch and just not use the video bit – this is in fact what I have at my work desk. The trouble is that some of them try to be too clever by doing things like not switching to an input with no video signal present. Anyway, the engineer in me weeps at the wasted components.
[2] There are probably cases where it would make sense to switch other USB peripherals that might normally be connected to a monitor based hub, and I expect there may be others when this wouldn’t be desirable. I expect it would be best to keep things limited to just keyboard and mouse.
[3] Double tapping ‘scroll lock’ to switch between my work laptop and microserver is a lot quicker than the Source->DVI/Displayport->Source dance I have to do to change inputs on my monitor.
[4] I am left wondering what monitor makers expect us to do with those multiple inputs, particularly when there are many of the same type (e.g. my monitor at home has 2 x DL-DVI so the multitude of inputs isn’t just to cater for a variety of different types of source – you’re expected to have many computers attached to the same screen)? Do they think we just have loads of keyboards on the same desk – perhaps stacked on stands like an 80s synth band?

2 Responses to “KVM mort”

  1. 1 KJ

    If all you want is to have a KM switch without the V, using simple keystrokes to switch machines: http://synergy-foss.org/

    • Thanks. Ken also asked why I didn’t just use Synergy (or VNC). Sadly it doesn’t help in this case as at work the machines are on different networks, and at home one of the machines is a gaming rig so I need raw graphics (if I’m ever using that machine for anything else then I just use RDP).

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