Good to know: What is PS/2?

06.10.2021

Nowadays it is hardly used any more, but its bright colors often catch the eye: the PS/2 interface. In this article, we explain what such a connection is used for and which of our Mini PCs are equipped with it.

The PS/2 interface is a serial interface for input devices such as a mouse or keyboard (rarely: trackball or graphics tablet). It was used on PCs for a long time, but has been almost completely replaced by USB connections. Nevertheless, due to certain technical differences (such as direct access via interrupts), it is still installed in many mainboards today.

The structure of a PS/2 interface

A PS/2 connection consists of 6 pins, with the following tasks:

Pin 1: Data transmission
Pin 2 & 6: not connected
Pin 3: Ground connection
Pin 4: Supply voltage (+5V)
Pin 5: Clock signal

There are basically two types of PS/2 interfaces, one with two sockets (green: mouse and purple: keyboard; see Fig. 1) and one split, to which both can be connected (half green, half purple; see Fig. 2).

Advantages of a PS/2 interface

In certain applications, however, a PS/2 interface also has advantages over USB. Firstly, the USB always transmits six commands simultaneously from the keyboard to the computer. This may not be enough for a fast bettor. The PS/2 connection, on the other hand, transmits continuously, which reduces latency. On the other hand, this connection is also interesting for security reasons: While the USB port can also be "misused" for other devices, PS/2 is only suitable for mouse and keyboard.

However, a keyboard that is used via the PS/2 connection cannot be unplugged during operation without causing a crash. USB is much more flexible here thanks to hot plugging.

spo-comm Mini-PCs with PS/2 connection:

In the spo-comm Mini-PC series, two systems are equipped with a PS/2 interface. The NINETEEN Q370 is equipped with two sockets and the NOVA Q170 with one split socket.

Discover the NINETEEN Q370

Discover the NOVA Q170