One for the hardware types.

Although presumably if you simply hard switch a USB mouse then its going to look like its been disconnected from one machine and then connected to the next. The USB KVM switches usually maintain the illusion that it remains connected to all the machines at the same time.

No idea, but I have seen hardware converters for both directions on the web, and I do not mean just connector changingthere is one here I have that allows one usb to handle a ps2 mouse and a keyboard on the same lead. Brian

Depends how 'intelligent' the mouse is, if e.g. it has configurable DPI and programmable buttons, then each O/S might send different settings and get confused when switching computers ... or the delay in plug'n'playing the mouse when swapping ports might be annoying.

I suppose I could try a cheap USB switch and see if it works. Obviously, I'd need one which can be remote switched to do what I want.

I have certainly seen issues even on some proper KVMs when switching between machines with different OSs because the mouse configuration maintained by the KVM is not consistent with each OS.

Tell me about it. There are three KVMs in regular use here, and each has a mixture of Windows and FreeBSD machines attached to it (and one has other weird things).

The Aten is the *only* one to preserve state properly and reliably.

Did think USB was meant to be 'hot' plugable. Unlike older ports.

It is, but normally KVMs present an illusion to the computer that the mouse remains connected at all times. So no delays in it detecting and re mounting the device on each switch.

I should have reiterated that both mouse and keyboard are actually PS/2!

My old cordless mouse was one of those that was USB, but supplied with a USB to PS2 adaptor. I think of a type known as quadrature?

Converters that allow PS/2 devices to be connected to a computer via USB are fairly common - although many are crap. A common failing for example is not supporting the \ key on UK keyboards. Others work but suffer random lock-ups.

The converters for going the other way (i.e. USB peripherals into a pair of PS/2 connections) seem far rarer. The only reasonable one I found was the pricey black box one which works quite well but does not seem to support the flasher keyboards.