Understanding Three Common Keyboard Styles


C’mon man! There is no such thing as a serial keyboard! Like anyone else, I understand the need to simplify the descriptions of different kinds of technology, but one thing must be reaffirmed: keyboards never plug into a serial port on a computer, normally anyway.

Let’s go over a few of the different types of keyboards to help people keep them properly sorted.

AT style, 5 Pin DIN

Both the original PC and the AT keyboard had a round, 5 pin DIN connector. These connectors came from a German standard that arranged the pins in a semi-circular, smiling, pattern. The plugs on these keyboards are larger than those found on newer keyboards (13.2 millimeter diameter) and are thus easily distinguishable.

Motherboards that use the 5 pin DIN keyboard connector were called “AT” form factor boards. Keyboards with this connector seem to be what most people are talking about when they refer to a “serial” keyboard.

PS/2 style, mini DIN

PS/2 keyboards feature a smaller, mini-DIN connector that has six pins. The jacks for these keyboards on computers are frequently marked purple, while the identical-looking PS2 mouse port is usually colored green.

Older keyboards are generally compatible with the PS2 keyboard port and adapters that convert the 5 pin DIN to the 6 pin mini DIN were commonplace at the time when both styles were simultaneously in use.

Motherboards using the PS/2 style keyboard connector are mostly “ATX” form factor boards.

Unlike the older AT style keyboards, PS/2 keyboards usually are not hot-swappable. This means that when replacing one, the computer should first be turned off.

USB keyboards

Technically, USB is a serial port, but this is not what most people refer to when they say “serial keyboard.” In fact, most people just call them “USB keyboards.” These are the most common keyboard interface right now and are hot-swappable. These keyboards are fitted with the ubiquitous USB connector and are virtually universal in their compatibility with any computer that is equipped with a USB port.

Now that you have the terminology straight, you know that you do not have a serial keyboard, so what kind of keyboard do you have?


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