Using Your Old PC's Keyboard and Mouse with a Mac

If you’re switching to a Mac from a PC, you don’t have to discard all your old PC equipment and buy new. In fact, you may even be able to connect your PC’s keyboard and mouse to your new Mac. When deciding whether you can use a keyboard or mouse you already have on your Mac, here’s the short version of the story:

A two-button scroll-wheel mouse with a wire coming out of it that has a USB connector — a flat rectangular metal plug about the size of a fingernail — at the other end is worth keeping.
A Windows keyboard with a USB connector will work fine, but a couple of keys are labeled differently from Mac keyboards, which may make it more trouble than it’s worth.

Mac keyboards have two special keys in the lowest row, to the left of the spacebar. One is labeled option, and to its right is a key with an Apple logo and a fan symbol, known as the Command key in Apple-ese. On PC keyboards, these two keys are the Windows key and the Alt key, respectively. If you just plug a PC keyboard into a Mac, the Windows key works as the Command key, and the Alt key works as the Option key. Unfortunately, their positions are reversed from where they are on Mac keyboardsYou can buy a piece of software called DoubleCommand that lets you reverse these keys.
If you have an old keyboard, buy something new. The mice and keyboards that came with computers in the 1980s used an RS-232 serial port connection. These are useless. Old Apple USB keyboards work fine on current Macs. If you have an older Apple keyboard or mouse with a round plug (Apple Desktop Bus), you can get an ADB-to-USB converter, but it is probably not worth the bother.

You should also consider how your keyboard and mouse connect to your PC. The three most common methods are a USB cable, a PS/2 cable, and wireless:

USB cables should work just fine with your Mac.
PS/2 connectors are round and have a pastel-colored shell. PS/2 won’t work with your Mac directly, but adapters are available. Be sure that you get the kind of adapter that converts PS/2 devices to USB and not the other way around, which is much more common. Also make sure that the manufacturer supports Macs.

These days, many manufacturers make only USB keyboards and mice and include an adapter that converts it to PS/2. So you should take a closer look at what you think is a PS/2 plug to see whether it is just one of these adapters, in which case you’re in luck — just pull the USB plug out of the adapter and plug it into your Mac.
Wireless devices have a built-in radio transmitter instead of a wire. The receiver is often in a finger-sized pod that plugs into the computer, or it can be built in. Some devices transmit using technology that’s proprietary to the maker; others use Bluetooth. Most Macs come with Bluetooth inside (it’s not included in the lowest-cost iMac, and it’s an option on the Mac Pro), and Bluetooth devices generally work with Bluetooth-equipped Macs, at least at some basic level. But you may need special software to take full advantage of this feature on a Mac. A wireless device that uses a USB receiver module and a proprietary transmission scheme may need special software as well. Check with the manufacturer in either case.