KVM switches are hardware devices that allow IT personnel to use a single keyboard, video monitor, and mouse (KVM) to control more than one computer at a time. They reduce the number of peripherals that data centers and server farms require, enabling businesses to conserve space, cut power consumption, simplify cabling, and reduce expenses. Most KVM switches are metal enclosures with a plastic faceplate and light emitting diode (LED) indicators. Buttons on the front of the device control switching among computers. Ports on the back are used to connect peripherals and client devices. Scalable, 8-port and 16-port expanders that provide cross-platform support allow IT personnel to increase the number of computers that can be managed from a single switch. Some KVM switches are used in on-site applications to manage Ethernet-based local area networks (LANs). Others are used in enterprise-level applications that permit remote monitoring and support transmission control protocol/ Internet protocol (TCP/IP) or wireless fidelity (Wi-Fi) communications.
Important specifications for KVM switches include the number of computers that a switch can manage concurrently and the number of users that a switch can handle simultaneously. KVM switches also vary in terms of monitor resolution, speed, and operating temperature. Common keyboard and mouse emulation types include universal serial bus (USB) and PS/2. In terms of platforms, KVM switches support computers that run Windows®, UNIX®, Linux®, MacOS® or SunOS® operating systems. Windows is a registered trademark of Microsoft Corporation. UNIX is a registered trademark of The Open Group. Linux is a registered trademark of Linus Torvalds. MacOS is a registered trademark of Apple Computers, Inc. SunOS is a registered trademark of Sun Microsystems, Inc.
KVM switches are available with many features. Some include audio or visual indicators that display information about switching, or indicate that a specific computer is in use. Others include an integrated keyboard, video monitor, and mouse. KVM switches with a serial port provide serial switching capabilities. Devices that are hot pluggable allow IT personnel to connect computers, keyboards, monitor and mice while a switch is in use. Plug-and-play devices configure installed system components automatically, or with minimal user intervention. Many KVM switches include surge protection and mount in standard 19" telecommunications racks or other data center structures. On-screen display capability (OSD) and password security are commonly available. Other features include low bandwidth consumption, advanced video detection, fast switch buttons, dual console support, dual video graphics array (VGA) cards, and power-free operation.