What is a KVM switch?

The KVM switch (KVM = Keyboard– Video – Mouse) connects 2 to 64 computers, one keyboard, a mouse, in part also USB devices and speaker, If several KVM switches are linked together, several computers can be connected and controlled with just one mouse and keyboard. An excellent solution to avoid cable clutter.

Versions of KVM switches

While mouse, monitorand keyboard are connected directly to the KVM switch, there is to connect the computer to be operated with the switch next to the standard cable (VGA + 2xPS / 2, DVI, USB) proprietary cable (DB25 connector on the KVM switch). The advantage of this cable is that the connection can be made faster and mechanically stable. Modular port switches use one adapter per computer for their respective ports. So can be used for the cables in between same cable types as in the Ethernet.
switching is possible with the key, a hotkey or a rotary switch. Thanks to the emulation of the mouse and keyboard, the KVM switch ensures that the connected computer keyboard and mouse are perceived as continuously connected. Your settings will be saved individually for each computer. This avoids disruptions in the drivers, the operating systems and the respective hardware. LEDs or numeric displays on the KVM switch boxes indicate which computer is being used.
For quad-video or dual video in a workstation with two or four monitors, there are special KVM switches or other models can be coupled together and switch synchronously.
So-called „matrix KVM switches“ or „multi-user KVM switches“ have connections for at least two workstations. These allow the simultaneous work of several administrators or users on different computers. A configuration can limit the often unwanted concurrent access of multiple users to the same computer. These KVM switches have an elaborate security system that restricts individual users to specific computers and password protection. The selection, as well as the configuration of the computer via so-called OSD menus.

KVM over IP

With a KVM over IP switch, the monitor, mouse and keyboard are not connected directly to the KVM switch, but to a networked computer with specialized software or a Java-based browser. The screen outputs of the encoders are converted by the KVM switch, as well as mouse and keyboard information sent to the switch. This makes a remote control of any workstation via the Internet or in your own network possible, in part, via ISDN or modem.
KVM over IP has some disadvantages:
– Complex security measures are necessary
– slow screen layout
– limited color depth
– erratic mouse movements
– higher cost

KVM Extender

These are used to extend the distance between the switch and the computer or the workplace and for better transmission of signals without loss of quality. Other cable types are used, such as Cat5 cables with modular connections. A transmitter and a receiver are connected at both ends. These two devices have to fit together and are usually sold as a pair.

Conclusion

These KVM switches not only help eliminate the clutter by using just one mouse and keyboard, they also provide the ability to change the BIOS settings of remote computers.