▷ Differences between ps / 2 vs usb which connector is better for keyboard and mouse?

Have you ever stopped to think about the difference between PS / 2 vs USB ? Why do you think almost all keyboards are currently connected via USB instead of PS / 2? In this article we will try to get out of doubts learning how these ports of our PC work and what advantages and disadvantages each one of them provide.

Index of contents

Something that we can notice day by day in the new equipment, boards, laptops and peripherals that come onto the market, is the need for faster and more generic connections in order to use them in the most complete range of products possible. And it is that our purchase largely depends on the connectors, since we always look for the largest number of them and also that they are the latest versions, for example, portable hard drives, monitors, graphics cards, etc.

However, today we have almost forgotten a connector that has been basic throughout the years in our PC, it is the PS / 2, used to connect our keyboard and mouse, and that on many boards today shines for its absence. There are also not too many peripherals on the market with PS / 2 connectors, the USB interface monopolizing almost all of the peripherals.

What is the PS / 2 connector

This connector was first implemented by IBM in 1987, hence its name: " IBM Personal System / 2 ". It has been used for years to connect keyboards and mice and has a serial data exchange system, as well as the USB port, and bi-directional for keyboards.

The interface of this connector is directly managed by the motherboard and one of the most relevant things is that it does not support Plug and Play, or hot connections. Because of this, if we connect or disconnect a peripheral to it, we will have to restart the machine for the changes to take effect. Moreover, the fact that we do not damage internal components of the board when connecting and disconnecting a peripheral hot, is due to the protection that the microcontroller incorporates from it.

Currently we find, in most cases, a single connector with the ability to connect, either a mouse or a keyboard. This interface works at 5V and 100 mA, so it is not capable of supplying additional power to the connected peripherals, so we will not be able to charge a Mobile or connect a mouse with lighting.

In addition to transporting serial data, this connector works via interrupt signals. An interrupt signal functions as an event that reaches the CPU directly and notifies that the peripheral has made a move or an action, and this must be processed immediately. Thanks to this system, the latency of a PS / 2 connection is even better than that of a USB one.

Another of the main characteristics of a PS / 2 port with a connected keyboard, is that we can make use of the N-Key Rollover function, and the keyboard will register absolutely all the keys that we press simultaneously on it. Despite this, few keyboards can currently be found with a PS / 2 interface, and the ones that do exist are very basic.

If it is faster, why do we use the USB port

As for the USB port, we all know this type of interface and its benefits in terms of data exchange speed. It also transmits the data in series, but not through the interrupt system, but with the Polling method, which is the frequency with which a device reports its position to the computer. A device connected to a USB port maintains constant communication with the processing chip, and that is why it theoretically introduces more latency to communication than on the PS / 2 port. Although for practical purposes, due to the powerful hardware that we currently have, we will not notice any difference between USB and PS / 2.

In addition to this, a main reason why USB is used is precisely because of its wide compatibility and its Plug and Play capacity. We can connect and disconnect a peripheral without restarting the equipment and making immediate use of it. In addition, this port supplies power to the peripherals, since they work at 5V and between 500 and 900 mA, even higher in USB 3.1 Gen2. In addition to data transfer, we can have a lighting system in the peripherals or we can even charge mobiles.

Continuing with the advantages, we have a very simple one, that of availability and capacity for many connection cycles. The USB port is present in absolutely all motherboards today and they also have no pin-shaped pins that, after a number of connections and disconnections, will most likely end up breaking.

The good thing about a USB connector is the possibility of connecting it to a PS / 2 converter where we can separate Mouse and keyboard, in case of wireless combos.

Which connector is better

Well, today and for the advantages we have provided, the USB connector is clearly better. Wide compatibility, ability to provide power and is present in all equipment, what else do we need?

We will only be interested in using the PS / 2 port on older computers, where the processor is not too powerful and the chipset has little capacity. This is because the lanes that are used for the USB ports are normally shared on all connectors and go directly to the Chipset or CPU. The fact of having many peripherals connected to the USB, will be a symptom of slower and consequently, higher LAG.

Otherwise, it is difficult to find a mouse or keyboard with PS / 2, so, globally, you will use USB 98% of the time.

You may also be interested in these tutorials:

What type of keyboard and mouse do you use? If you have any questions or need to know more about this topic, ask us in the comment box.