At the back of some PCs, a small round connector can still accommodate a keyboard or mouse: the PS/2 port. Introduced with IBM Personal System/2 computers in 1987, it is nevertheless not found on every current machine. Its presence serves specific needs, but does not mean it is faster or better suited than USB for everyday use.
A connector inherited from IBM PCs
The name PS/2 comes from the Personal System/2 range, launched by IBM in 1987. Among other things, these computers incorporated features directly into the motherboard, whereas some earlier models relied more heavily on expansion cards. Keyboards and mice could be connected to ports of this type.
The PS/2 connector is a small, round port, generally associated with a keyboard or mouse. On some PCs, two separate ports are positioned side by side. The usual colour coding distinguishes the keyboard port, often purple, from the mouse port, often green. However, this is not a guarantee: check the manufacturer’s information and the model’s documentation, as configurations vary.
Some machines also have a single PS/2 port intended for both types of peripheral, subject to the conditions specified by their manufacturer. So you should not assume from the presence of a round socket alone that it will accept both a keyboard and a mouse interchangeably.
Why PS/2 gave way to USB
USB has established itself as a versatile connection for computer peripherals. It allows many devices to be connected using the same type of socket and has evolved over successive generations. For most users, USB keyboards and mice are therefore the simplest choice, provided a suitable port is available.
PS/2, by contrast, has a more limited use: it works only with compatible peripherals. It is not found on every PC, and manufacturers may omit it to free up space on the rear panel or prioritise other connections. Its presence on a motherboard does not mean it is an essential feature or particularly useful to every user.
When might it still be useful?
A PS/2 port can be useful if you have a keyboard or mouse designed for this connection, or if a computing environment specifically requires PS/2 peripherals. Some professional uses may restrict the use of USB ports, but this depends on the organisation’s rules: the presence of a PS/2 port does not, on its own, guarantee security.
It can also come in handy when a support issue prevents a USB keyboard from working in a particular situation. But it is not a universal solution: the outcome depends on the computer, its configuration and the peripheral. Before relying on this port, it is best to consult the documentation for the motherboard or PC.
Overclocking enthusiasts are sometimes cited as users who might find it useful. Overclocking involves running certain components at frequencies higher than their usual settings. This does not mean that PS/2 systematically reduces response time or provides a measurable advantage over USB. Comparable measurements taken under specific conditions would be needed to support such a claim.
Adapter: compatibility matters
A physical adapter does not automatically make a keyboard or mouse compatible with a PS/2 port. Some peripherals are designed to work with both types of connection; others are not. The shape of the plug is not enough to tell. Check the peripheral manufacturer’s information and the computer’s documentation before buying or connecting an adapter.
The same caution applies to coloured ports: they offer a common indication of their intended use, but do not guarantee that every peripheral will be recognised. If the computer does not have a PS/2 socket, a USB port is generally the straightforward choice for a USB peripheral.
PS/2 is therefore less a forgotten connection than a niche option retained on some computers. For a standard setup, there is no reason to replace a USB keyboard or mouse with a PS/2 model. Its value depends on a specific need and verified compatibility, not on its age or its presence on a specification sheet.
References
- The PS/2 — IBM
- Nobody uses it any more, but this port has been on every PC for 40 years — so what is it for? — Phonandroid
Photograph: Nicolasfoster — Wikimedia Commons — CC0 1.0.
