What is KVM Switch
A KVM (keyboard, video, and mouse) switch is a hardware device that allows a user to control multiple computers from a single keyboard, video display monitor and mouse. KVM switches are often found in data centers where multiple servers are placed in a single rack. By pressing a button on the KVM switch, the administrator can change control from one server to the next. Using a KVM switch can save the administrator the cost of purchasing a dedicated keyboard; monitor and mouse for each computer, save space in the server room and limit cable clutter.
Uses of KVM Switch
A user connects a monitor, keyboard, and mouse (and audio if provided for) to the console port on the KVM device and the computers to the other ports.
KVMs can offer different methods of connecting to the computers. Depending on the port density and the type of connection, the KVM may present native connectors on the device where standard cables connect. Another method is a single DB25 or similar connector per port that connects to a special cable which has the video, keyboard and mouse connectors at the computer end. The advantage of the special cable approach is a reduction in the number of cables at the KVM. The disadvantage is the cost of these cables.
Control is switched from one computer to another by the use of a switch or buttons on the KVM device, with the KVM passing the signals between the computers and the keyboard, mouse and monitor depending on which computer is currently selected. Most electronic KVMs allow control to be switched through keyboard commands (such as hitting a certain key, often Scroll Lock, rapidly two or three times) or via an On Screen Display (OSD) menu.