What is a KVM switch?

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Switches and Valves
Switches and Valves
Vac1 / Shutterstock.com

If you run multiple computers, your set of mice, keyboards, and monitors can quickly get out of hand. KVM switches can reduce the number of peripherals to a minimum using relatively simple hardware or software. Let’s take a look at how they work.

What is a KVM switch and how does it work?

In simple terms, a KVM switch allows you to switch between different computer sources (or computer cabinets) while using the same keyboard, monitor, and mouse; in fact, that’s what KVM stands for: Keyboard, Video, Mouse. That means if you have multiple PCs that you need to work with, you don’t have to buy separate monitors, keyboards, and mice for each PC. Instead, just buy one of each and use the switch to go from one PC to another.

That said, the term KVM is a bit misleading, and while the original KVM switches only handled those three, modern switches often handle more, including things like audio and USB ports. There are even KVM switches that switch between a single input, like this 3-port HDMI switcher from Gana, though they’re usually referred to simply by the data they handle, like an audio switcher or a keyboard switcher.

So how exactly do they work? Well, in the old days, plug-and-play technology didn’t exist, so every time you wanted to change a keyboard or mouse, you had to restart the computer so the CPU could detect any peripherals. While this is no longer the case, KVM switches still do something similar in that they trick the CPU into thinking there is a connection, so that when you’re done switching, everything works fine.

How it does this is a bit complex, but basically, it emulates computer peripherals and constantly maintains a “dummy” signal. When you switch, the KVM switch replaces the emulated signal with the actual signal from your peripheral, providing a smooth, seamless transition.

KVM Switch Types Explained

KVM switches tend to come in two main versions: hardware and software.

Hardware switches are the most common and the type you are most likely to come across or use. For example, consumer-grade KVMs can typically switch between two and four sources, though some can go as high as eight, and tend to be marketed a little more towards those running small offices or businesses. For large corporations, some of the larger KVM switches can go up to 64, and are sometimes connected to a server running many virtual machines that multiple people need to access.

In addition to the number of sources you can switch between, there is also the type of video, with the most common KVM switches being for VGA. Fortunately, KVM switches with HDMI and Display Port are becoming more common, but they tend to be a bit more expensive than VGA.

Another option is how many monitors you want to support, with one being the most common option and three available, though rare. Again, you’re not likely to find an HDMI KVM that drives two or more monitors, although the technology is becoming more common as of this writing in early 2022. Perhaps in a few years, we could see HDMI as the default, rather than than VGA, at least in the consumer market.

As for software KVM switches, they are also a bit of a misnomer as they generally don’t support switching monitors and are therefore technically KM switches. They work by installing an application on your computer that allows you to directly control a mouse and keyboard on any computer that is connected to your network. These tend to be quite useful in large corporations with many servers that need to be reviewed by different IT and management people.

Do I need a KVM switch?

KVM switches can be quite useful for personal use, although you’re thinking of spending around $50 on the low end like for this KVM PWAY, it largely depends on your usage. If you find that you’re constantly going back and forth between two PCs, then the $50 cost of entry might well be worth it. Or, if you don’t have a lot of desk space and can only fit a monitor, mouse, and keyboard, a KVM switch can be a great investment.

An affordable KVM switch

KVM Switch Box 4 HDMI Ports

Easily control four different systems with this KVM switch that supports HDMI connections and won’t break the bank.

Another option is to use a software KVM and just have an additional monitor running; that way you at least save some space while still being able to functionally use your other PC source.

If you have a business that tends to handle a large number of servers or machines, a KVM switch can also be very useful, especially software ones, as they allow you to remotely access devices, saving you a trip to the location.

RELATED: How to control multiple PCs with one keyboard using Synergy