The purple plug on a keyboard is specifically a PS/2 plug, a distinct type of connector that was once a standard for connecting keyboards to computers. This specific color-coding helped users identify the correct port for their keyboard peripheral.
Understanding the PS/2 Connector
The PS/2 connector, named after IBM's Personal System/2 series of computers introduced in the late 1980s, became a widespread standard for connecting both keyboards and mice to PCs for many years.
Key Characteristics:
- Color-Coding: The purple PS/2 plug is found at the end of the cable attached to your keyboard. This purple plug is designed to be inserted into a matching purple PS/2 port on the back of your computer. Similarly, a green PS/2 plug is used for mice, fitting into a green port, making it easy to distinguish between the two connections.
- Physical Design: A PS/2 plug is a small, round 6-pin mini-DIN connector.
- Dedicated Connection: PS/2 ports provide a direct, dedicated connection to the computer's system. This direct link was valued for its reliable input in earlier computing eras.
PS/2 vs. USB: A Comparison
While PS/2 was once the predominant standard, it has largely been replaced by Universal Serial Bus (USB) technology due to USB's greater versatility, ease of use, and hot-swapping capabilities.
| Feature | PS/2 Keyboard Connector (Purple) | USB Keyboard Connector (Type-A) |
|---|---|---|
| Color-Code | Purple (for keyboard) | Typically black or blue (standard USB color) |
| Connector Type | 6-pin mini-DIN | Rectangular (Type-A) |
| Hot-Swapping | Generally not hot-swappable (requires restart) | Hot-swappable (can plug/unplug while PC is on) |
| Versatility | Keyboard-specific | Multi-purpose (keyboard, mouse, storage, etc.) |
| Prevalence | Found on older computers and KVM switches | Standard on nearly all modern computers |
For more detailed technical specifications on various connector types, you can explore resources like the Wikipedia page on PS/2 ports.
Where You Might Still Encounter PS/2
Although most modern keyboards use USB, PS/2 connections can still be found in specific scenarios:
- Older Computer Systems: Many desktop computers manufactured before the mid-2000s are equipped with PS/2 ports.
- KVM Switches: Keyboard, Video, Mouse (KVM) switches, particularly older models, often use PS/2 ports to connect to multiple computers, allowing a single set of peripherals to control them.
- Specialized Hardware: Some niche motherboards or industrial PCs might still include PS/2 ports for compatibility with legacy equipment or for their dedicated input characteristics.
If you have an older keyboard with a purple PS/2 plug and a newer computer without a PS/2 port, a PS/2 to USB adapter can sometimes be used to connect it. However, compatibility can vary, and for optimal performance and convenience, modern USB keyboards are generally recommended for current computer setups.
