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KVM Switch

mossgrove
Grafter
Posts: 68
Registered: 18-08-2007

KVM Switch

Can anyone recommend a KVswitch to use with USB keyboard and mouse, and that will support 1680 x 1050 widescreen resolution?Huh
11 REPLIES
alanb
Grafter
Posts: 459
Registered: 24-05-2007

Re: KVM Switch

Any cheapo no-name KVM switch should do it.
I recently bought a Chinese made, unbranded KVM that claims support up to 1920 x 1440, for 30 quid, at a computer fair. (That was for a 4 port, PS/2 type.)
I've seen one in on-line shops, that looks like it came from the same factory, with Edimax branding on it, which costs about 50+ quid.
Community Veteran
Posts: 1,850
Registered: 11-08-2007

Re: KVM Switch

jackoab
Grafter
Posts: 368
Registered: 14-08-2007

Re: KVM Switch

Just a word of warning about the Edimax swich indicated, I purchased one of these from Novotech last November and it still isn't funcional, it has been back to Edimax once and I have been in contact with them for the last 3 months and all they will say is that it's not compatable with my keyboard and mouse which are a Logitech set. As it stands at the moment I'm stuck with the switch which doesn't work and neither Novotech or Edimax seem interested, Jack.
alanb
Grafter
Posts: 459
Registered: 24-05-2007

Re: KVM Switch

Unfortunately that's true for lot's of KVM switches, including professional models intended for use in data-centres.
The problem is with Logitech mice, which use an extended (and therefore non-standard) communications protocol that is not supported by most KVM manufacturers.
As a rule of thumb, if the KVN speciication does not mention Logitech support, it's best to be cautious and assume that a Logitech mouse is not going to work.
jackoab
Grafter
Posts: 368
Registered: 14-08-2007

Re: KVM Switch

I would just like to add that I tried it with a Microsoft set with the same results, from the advice I was given by Edimax it would appear it only works with a very basic setup with no extra keys or functions, Jack.
Tracer
Grafter
Posts: 76
Registered: 17-07-2007

Re: KVM Switch

I just purchased a TRENDnet KVM which supports 1680 x 1050 and works with my USB logitech MX510 no problem.
Its got switchable USB ports/Audio/PS2.
Was abit picky on normal XP but XP 64bit had no problems with it.
alanb
Grafter
Posts: 459
Registered: 24-05-2007

Re: KVM Switch

Quote from: jac2285
I would just like to add that I tried it with a Microsoft set with the same results, from the advice I was given by Edimax it would appear it only works with a very basic setup with no extra keys or functions, Jack.

That's a shame. Some Microsoft kit also have non-standard extensions that a KVM won't recognise. Though these days, most KVM switches do seem to be Intellimouse compatible, at least.
Also your operating system can make a difference. Linux is far more picky about accepting input from a KVM than windows is. I've never found out why, but some versions of Linux distributions just do not like some KVM equipment, and compatibility seems to vary as Linux versions change. If you get a combination that doesn't work, it's just tough luck, there seems to be little you can do except look for alternatives that do work together.
It's all a bit hit-and-miss really. Less so now-a-days, but you still sometimes have to compromise if you want to use a KVM. I have given up buying expensive mice because of these sort of problems. Every time I buy a new KVM, I drag out my favourite Logitech trackball from the cupboard in the hope that it may work with the new switch, but I've had no luck so far.
Community Veteran
Posts: 1,236
Registered: 02-08-2007

Re: KVM Switch

Quote from: alanb
Any cheapo no-name KVM switch should do it.

The problem I have found with cheap ones is that they will not fool the computers into thinking that there is a keyboard attached if thay are not switched to that computer. Obviously you can set the BIOS to not halt on keyboard errors but sometimes Windows has a problem with it. Linux is fine. That is why with my Linux and Windows servers the switch has to always be set to the Windows server unless I need to switch to the Linux server for a short time. Otherwise windows will not start if I reboot remotely.
Community Veteran
Posts: 1,850
Registered: 11-08-2007

Re: KVM Switch

when i used windows i had to switch the computers on in a specific sequence, or no keyboard/mouse.  with two linux boxes on the switch it doesn't matter which i start first.  must try kvm with my wireless microsoft multimedia keyboard and see if it will co-operate.
alanb
Grafter
Posts: 459
Registered: 24-05-2007

Re: KVM Switch

Sean, are you using mechanical switches?  (I mean the type that literally switch the wires between different keyboard and mouse sockets.)
A proper KVM does emulation of keyboard and mouse so that every PC always see what it believes is a keyboard and mouse, so they should never suffer a problem like the one you've described.
Some of the cheaper KVMs have phantom power supplies - meaning they derive power from a PS/2 or USB port on one of the PCs. This can make them sensitive to the order that  PCs are started. Usually this can be solved by connecting the KVM to a little wall-wart type PSU of the correct voltage (if the KVM has a suitable socket, of course.)
Community Veteran
Posts: 1,236
Registered: 02-08-2007

Re: KVM Switch

The first one was mechanical. It is the one that can be seen the photo on my site (between the servers and the ups). The newer one is not mechanical however it does have the same problem. It does get power from the ps/2 connection. I think I paid about £10 on eBay for this.
It is not really an issue as I cannot remember the last time I needed to work at either machine locally. If I was using a KVM for 2 desktop machines I would definitely spend a little more money.