KVM Splitter

A KVM (Keyboard Video Mouse) Splitter, also known as a Reverse KVM switch, is a hardware device that allows users to control a single computer from one or more sets of keyboards, video monitors, and mice. With a KVM splitter, users access the connected computer consecutively rather than simultaneously. It differs from a KVM Switch which allows multiple computers to be controlled, usually, by a single keyboard, monitor and mouse.
Types.
There are two main functional designs of KVM splitters:
Signals.
Common input and output video signals for KVM splitters include HDMI, DVI, and VGA. Keyboard and mouse input and output signals are PS/2 or USB. Some KVM splitters also offer additional USB input ports to connect peripheral devices, such as external hard disk drives and printers, which can be shared across all users.
Monitor.
As one computer is feeding video for multiple monitors, there are a few ways KVM splitters can handle the potentially different DDC and EDID transmissions from the monitors.
Usage.
A KVM Splitter can be used by multiple users to control a single computer from multiple locations. Any user can access the computer and its programs from their workstation. There are a few activation modes KVM splitters operate in, which limits simultaneous user activity. 
The method of switching from one user to another depends on the KVM splitter and supported modes of operation. Rotary switches, active electronic switches, push buttons or automatic activation via keystrokes/mouse are some of the switching methods commonly used.
KVM Splitters can be combined with KVM switches and KVM extenders (which provide a way to relocate keyboard, monitor, and mouse to a far distance from the computer) to set up more complex configurations. For example, multiple users can access the same computer without the need for physical proximity to the computer. A common industrial application is to allow access to a computer located in a cleanroom from outside, to restrict the level of contamination. By providing access to multiple users through a KVM splitter, pollutants can be minimized by reducing the need for the users to enter the cleanroom.