View Full Version : Keyboard/mouse sharing: Am I boned?

May 14th, 2012, 04:25 PM
I think I have the worst possible setup here, I want to share my USB keyboard and mouse between a 486 but with the parts I have it seems unlikely.
My keyboard doesn't appear to work with a USB->PS/2 adapter and while I have room for a 2nd mouse on my desk, a second keyboard is definitely out.

I did have one idea about using a null modem cable and writing software to have my main PC emulate a serial mouse for the 486, but I need to do more research
before I spend any more time on it. Especially since it's been ages since I touched the win32 API and the fact I've never driven a serial port from Windows.
The keyboard is the biggest showstopper here though, any thoughts?

May 14th, 2012, 04:36 PM
Try a different keyboard?

May 14th, 2012, 04:37 PM
You could "downgrade" your daily keyboard and use a ps/2->usb adapter for your current system, then use a KVM to connect both systems to everything else. Not sure if there is a cheap KVM that supports both USB and ps/2/AT but I would think there would be.

May 14th, 2012, 04:40 PM
Try a different keyboard?

But it's soooooo coooommmmfffyyyyyyyyyy!

May 14th, 2012, 05:03 PM
I have a Microsoft Ergonomic (white) keyboard at work and it's ps/2, I'm using the adapter to connect it to my usb only desktop. Comfy keyboard when you're used to it, otherwise I'd be using an old clicky one like an M or clone.

May 14th, 2012, 05:29 PM
Look for a PS/2 and USB capable keyboard and mouse; one designed to work with both interfaces with an adapter to PS/2. It should work with a USB KVM switch which goes through a PS/2 adapter to the PS/2 system. The keyboard should handle the changes to which interface the system is working on. Might be a little challenging to find because the dual mode keyboards and mice are being cleared out.

I have a PS/2 equipped system and a USB system sharing a PS/2 KVM switch which in turn connects to both a PS/2 mouse and keyboard. The KVM switch is attached to the USB system through a PS/2-USB adapter. Amazingly, that whole kludgey setup actually mostly works except for a few minor issues:

The USB system will not activate the PS/2-USB converter right on startup so a USB keyboard will need to be attached in case of any problems before the OS gets loaded.
The PS/2 system gets the keyboard buffer filled up but only when I am trying to run BOCHS on the older system.
Wireless mice do not work when the KVM is switched between systems. Directly attach the wireless mouse's receiver to one system and share a wired mouse through the KVM.

May 14th, 2012, 08:22 PM
If worst comes to worst I'll swap out the keyboard, but I like it soo much.

Unless the USB->PS/2 adapters are wired differently for mice and keyboards since all I had on hand was one from a mouse.
Google searches tell me nothing if the keyboard (Logitech K120) is supposed to support the PS/2 protocol.

July 3rd, 2012, 04:19 PM
I have way way too many ps2 keyboards, i wish I could give you one

July 4th, 2012, 12:43 PM
Offtopic, but does anyone have ever tried to use a USB keyboard to connect to an old-DIN 486 system, through an USB-to-PS/2 adapter, and then through a PS/2 to old-DIN adapter?

July 4th, 2012, 05:28 PM
Haven't tried it, though I'm sure that there's many Geekhackers that have.

I picked up a few of these (http://www.ymouse.com/ymouse/whym08.php) on eBay for $9 shipped. I say a few, more like 4 of the red ones and a green one that I forget the function of (maybe for two mice via the same USB?)

I saw a review on geekhack that said that these worked great with the Model M and several other models, and well, I got 4 of them for less than the cost of the "blue cube" ps/2->USB adapter that most people use with their Model M's.

Specific to your situation, the website says that they're great for using USB keyboards with KVMs. At $59.95 MSRP, they're expensive, but they crop up on eBay from time to time for next to nothing.

July 4th, 2012, 05:42 PM
Seems to me everyone's talking about connecting a PS/2 (or DIN) keyboard/mouse to a USB port; lots of devices out there for that, but I think the OP wants to go the other way.

July 7th, 2012, 03:28 AM
Seems to me everyone's talking about connecting a PS/2 (or DIN) keyboard/mouse to a USB port; lots of devices out there for that, but I think the OP wants to go the other way.

Yes - I think the basic problem is that USB keyboards, like most USB devices, have a setup negotiation protocol that is not recognised by a PS/2 port driver, because there are many different keyboard variants that can require different drivers. It seems the simpler mouse protocols are made to be intelligible to a PS/2 port. The Y-connector is expensive because it includes some protocol translation intelligence in it - not just a passive pass-through like the USB > PS/2 mouse connector. I've never heard of a simple adapter for the keyboard. I have used a PS/2 KVM with a USB > PS/2 adapter for the mouse, but not the keyboard.