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[ The PC Guide | Systems and Components Reference Guide | Keyboards | Special Keyboard Features and Accessories ]

Mechanical and Interface Keyboard Adapters

As discussed in the section on the keyboard connector, there are two standard keyboard connectors used in the PC world: the 5-pin DIN ("AT") connector and the 6-pin "mini-DIN" ("PS/2") connector. They are electrically compatible but physically different.

Whenever there are two electrically similar items that are mechanically different in the PC world, adapters usually "appear" to change one into the other, and this is no exception. :^) Cheap ($5 or so) adapters exist that will let an older 5-pin keyboard plug into a newer PS/2-style keyboard port, or to let a newer keyboard work in an older PC (AT or later.) I call these mechanical adapters because they only change the configuration of the connectors, and do nothing electrically to the signals.

A mechanical keyboard interface connector adapter. This adapter
lets you use a newer keyboard that has a 6-pin mini-DIN connector,
on an older PC that takes a 5-pin DIN connector keyboard.

Newer keyboards use either the standard keyboard interface or USB. Some have a cable that terminates in two connectors, one for PS/2 and the other for USB. Others have a cable that terminates in a standard keyboard connector, and a mechanical adapter is provided that converts the standard (PS/2) keyboard connector into a USB connector.

Of course, the USB and regular keyboard interfaces are totally different electrically. This means a simple mechanical adapter of this sort will only function properly on a keyboard designed from the ground up to use both interfaces. One cannot plug a regular PS/2 keyboard into a mechanical PS/2 to USB adapter and expect it to work properly!

However, there are those that wish to do exactly that. For these users, several companies make interface adapters. These are adapters that change the PS/2 connection to USB both electrically and mechanically. Frankly, given what keyboards cost today and what they want for these adapters, I'm not really all that sure what the point is, but they are indeed out there. :^)

Mechanical adapters are the most commonly used, and they are so simple that there's not much to say about them. One caveat however is to be very careful when moving a PC if using one of these devices. The connectors are typically rigid and fairly long; they stick out from the back of the PC. If something hits the adapter hard from a strange angle, you risk snapping something off, possibly even damaging the motherboard.

Next: Keyboard Accessories

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