Mac Musings

How About a KVM Switch for USB Macs and PS/2 Windows PCs?

Daniel Knight - 2005.03.29

Apple is selling the Mac mini without a mouse and keyboard, telling computer owners (Mac and PC alike) that they can use their existing input devices.


Some of the time.

But not always.

For instance, I've got an antiquated Dell OptiPlex GX1, a 450 MHz Pentium III machine with Windows 98SE that's all the Windows computer I need - and more virus magnet than I care to deal with on a regular basis. I don't need it often, but there are a few things that you can't do on the Mac, such as voice chat with Yahoo Messenger.

PS/2 Ports

This old Windows PC may have USB ports, but it won't boot without a PS/2 mouse and keyboard attached. This raises an issue Apple has avoided - how can you use a PS/2 mouse and keyboard with a USB Mac?

You could use a USB Male to PS/2 Female adapter, such as this keyboard adapter from (also available in a mouse version). If Cyberguys can sell these for US$1.99, every Apple dealer who stocks the mini ought to keep a few on hand. There are even US$10-20 devices that will connect both a PS/2 mouse and keyboard to a single USB port.

Adding, not Switching

I use the same Logitech mouse and keyboard with my eMac and my Dell - and it's a genuine pain in the posterior. Plugging a USB cable into the side of the eMac is a breeze, but I can't boot the Dell without PS/2 devices. That means I either leave my old mouse and keyboard attached and connect the wireless mouse and keyboard to the Dell via USB, or I use the PS/2 mouse port and USB-to-PS/2 keyboard adapter to plug the Logitech wireless base to the Dell.

For someone who isn't replacing their Windows PC but instead wants to use it alongside their Mac, that's messy. There has to be a better way, but in my research, I haven't found it. [Update: Such a product does exist. See Using One Keyboard, Mouse, and Monitor with Your USB Mac and PS/2 Windows PCs.]

KVM for Macs and PCs

One of the most clever devices in the history of personal computing is the keyboard, video, mouse (KVM) switch. I've used Dr Bott MoniSwitches in both the ADB era and the USB era. Nice products, and if my Dell would boot without PS/2 devices connected, I'd be using one today.

There is no easy solution. There are USB-to-PS/2 keyboard and USB-to-PS/2 mouse adapters, but I haven't seen a single device that would let me use a USB mouse and keyboard with separate PS/2 mouse and keyboard ports.

It may not be possible.

My Logitech wireless combo is a switch hitter. It has USB for Macs and modern PCs, but it also includes a PS/2 mouse plug and a USB-to-PS/2 adapter for the Dell's keyboard port.

What I'd really love to see is a KVM switch (or even a keyboard/mouse one, since I have to use the eMac's built in display) that would let me connect my keyboard and mouse to both computers. When set to the Mac, it would pass the USB signal. When set to the Dell, it would use a PS/2 cable for the mouse and a USB-to-PS/2 adapter for the keyboard.

As Windows PCs slowly move to "legacy free" designs (no more PS/2 ports, but USB instead), there should be a growing market for people who want to keep an older PC in use alongside their newer PC or Mac.

I'm not calling for anything much more sophisticated than today's KVM switches, just something that includes USB and PS/2 ports and can work with both at the same time. (Some support USB or PS/2; none seem to support both at once.) A two-way switch is all I want. As far as I can tell, no such item exists. (Monitor switching would be nice for many users, but then we get into the VGA vs. DVI debate. That's the topic for tomorrow's column.)

Any takers? Or perhaps a reader can point me to an existing solution.

Just remember, it can't be too expensive. The Dell only set me back $115, so it wouldn't make sense to buy a KVM that cost as much as the computer did.