One for the hardware types.

Generally the PS/2->USB adapters are passive (perhaps coded with a short or a resistor between two pins) so when the mouse is plugged in, it looks to detect that and if it does it "boots" as a USB mouse, otherwise as a PS/2 mouse ... so the smarts are in the mouse, not the adapter.

I've got zero clue how many circuits etc are used in each - especially given the number of pins on PS2.

Bust are you saying a the PS2 switch in the KVM might work for USB if I can get all the connections correct? I'd be happy to make things if needed.

No, those adapters only allow the mouse they came with to work as either a PS2 or as a USB mouse, but your KVM will only work with a PS2 mouse anyway. Since the smally2 expects a USB mouse, looks like you need a DVI/USB KVM instead of DVI/PS2 ...

In the same way most KVM manufacturers are cagey about supporting wireless receivers for wireless mice, I daresay they wouldn't want to guarantee working with a smally2, my Aten DP/USB happens to work with a logitech universal receiver, but a few features of the mouse are lost, and the support is unofficial, I think my older Aten DVI/USB didn't work.

Possibly if it's one of those with a big mechanical switch, or relays. But most likely it's some logic gates redriving the signal, and they won't handle USB. So generally not.

Since this is uk.d-i-y, I suppose it might be possible to make an external relay box and hook it in to the KVM somehow...

Theo

I view a proper wired KVM solution as being one which needs to be rock solid which isn't compatible with anything "wireless".

There are smart keyboard adaptors, but not seen one for mice.

Best plan is a KVM that handles both. I am a *great* fan of the Aten ones; they work well, and unlike many others (I mean you, Belkin) they emulate well enough that you can boot another machine in the background without it screwing up.

I wasted a lot of money on inferior KVMs before I discovered these.

Snag is I want to retain the PS2 Acorn keyboard. Which works with both it and the PC, via the KVM. The Acorn as no USB, so can't use a USB keyboard.

Wonder if I could use a USB switch? Any method of making that work from the switching signal of the KVM?

I've no problems with building something. A USB switch linked in to the KVM would be just fine. Perhaps I'll need to look for some circuits.

Is there any switched volts on the PS2 connectors on the KVM that I could use?

Only thing I want wireless is the mouse. ;-)

If the KVM has a status LED per input port, you could hook a logic circuit from that using something like 4066B quad switch IC ...

Normally 4 out of the 6 PS/2 pins are GND, +5V, CLK, DATA (occasionally two DATA pins if designed to work with a Y splitter for keyboard and mouse on a single port, usually split green and purple, rather than one or the other)

Since the mouse is USB 1.1, it's only 12Mbps. So a DPDT relay may get away with it. The main thing is whether each machine is happy with the mouse being hot(un)plugged each time you switch, or whether they get confused.

It is possible you might need to power down the mouse while you switch over, to make sure it restarts attached to the new machine.

If the switch was the other way (two mice, one PC) they could be switching PS2 power. But the other way both PC outputs are inputting power to the KVM, so you can't tell.

There might be an LED or something you can tap into to extract which output is enabled.

Theo

Pretty unlikely

The basic passive adaptors won't work since they require the mouse to switch between PS/2 and USB. With the adaptor on they run USB protocol.

There are however active adaptors/protocol converters that will convert a true USB mouse and KB to PS/2 - I did get a seriously expensive one from Black Box in the hope of being able to run a modern gaming KB on my PS/2 KVM - alas it did not seem to recognise the more sophisticated keyboards. It did however work with the mouse. So chances are that would do it for you also.

(not sure if there is anything else similar out there that is cheaper - but there might be. Failing that I could flog you mine ;-))

What sort of switch does the KVM use? Can you attach a new switch to it that operates at the same time and wire up the connections as required on the new switch? Just a passive switch no electronics.

Yeah, but....

Can't you use VNC? Allows use of both machines at the same time, one windowed inside the other.

It's an Aten I have. However, if you don't select the PC when it is booting, the PS2 mouse won't work on it - might of course be different with USB.

Are you saying they do a version with DVI, PS2 and USB? (don't need the audio) That would probably get round my problem - at a cost, as they're not cheap.

Good thinking there. ;-)

A sequence of key presses on the keyboard. Which I like - saves having a switch cluttering up the place.

Not ideal. I don't always want them both on. They get switched off when not in use.