KVM switch

A KVM switch (with KVM being an abbreviation for "keyboard, video and mouse") is a hardware device that allows a user to control multiple computers from one or more sets of keyboards, video monitors, and mice. Although multiple computers are connected to the KVM, typically a smaller number of computers can be controlled at any given time. Modern devices have also added the ability to share other peripherals like USB devices and audio.

Before the mouse became relevant in server switching applications, the term Keyboard Video Switch (KVS) was used to describe keyboard and monitor switching devices. With the increased adoption of Microsoft Windows, the mouse and other I/O ports in peripheral switching became prevalent. Remigius Shatas, the founder of Cybex (a popular peripheral switch manufacturer at that time) expanded the initialism to Keyboard, Video and Mouse (KVM) in 1995. At the same time, Universal Serial Bus (USB) began to become the new industry standard for connecting computer peripherals.

As a result of the growing need to switch peripherals (such as touchscreens) in addition to the keyboard, mouse and monitor, some companies are now selling "KVMP" switch devices (standing for keyboard, video, mouse and peripheral).

With the popularity of USB—USB keyboards, mice, and I/O devices are still the most common devices connected to a KVM switch. The classes of KVM switches that are reviewed, are based on different types of core technologies in terms of how the KVM switch handles USB I/O devices—including keyboards, mice, touchscreen displays, etc. (USB-HID= USB Human Interface Device)

Limited*=supported, but does not allow USB re-enumeration, which not only causes long delays in switching, but also sometimes causes HPD (Hot-Plug Device) errors to the OS system(s).

Yes*=Latency time within 1 second while switching between channels/ports.

A KVM Switch is a hardware device, used in data centers, that allows the control of multiple computers from a single keyboard, monitor and mouse (KVM). This switch then allows data center personnel to connect to any server in the rack. A common example of home use is to enable the use of the full-size keyboard, mouse and monitor of the home PC with a portable device such as a laptop, tablet PC or PDA, or a computer using a different operating system.

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