The Raritan Blog

Understanding the Four Categories of KVM Switches

Hugo Lin
July 21, 2014

Back of KVM Switch Inputs

KVM Switch is a hardware device that allows you to control multiple computers via a single keyboard, monitor, and mouse (KVM).  The first KVM switch was created as a testing tool for motherboard and production server quality tests, and only supported video and keyboard since the mouse hadn’t been invented at that time.   And as computer technology continued to evolve, so did KVM switches which led to the development of a variety of types for different systems and applications. Here are the four categories of KVM switches. 

From a computer access and control perspective, the KVM switch can be categorized into two main types:

  • The single user KVM switch:  This is usually an entry-level KVM switch for small installations such as for SOHO or remote office.  It allows a single person to access as many computers as they need to form a single console. For instance, the MasterConsole® CAT MCCAT18 allows one person to access up to 8 servers.
  • The multi-user KVM switch: This is used for larger installations and data centers that required several users to manage a number of computers or servers.  The Paragon® II UMT1664 is a great example as it allows 16 users to access up to 64 servers.

From an application and technology perspective, KVM switches can be divided into the following two types:

  • The analog KVM switch:  Analog KVM switches are operated by having a direct cable connection from the computer to the KVM Switch to the console. The cables can be Coax or Cat5 depending on the switch.  For example, the EZ-108 uses coax cables to connect to servers, and MCCAT18 uses Cat5 cables.
  • The digital KVM switch:  Also known as a KVM over IP. These allow you to control your servers over any IP connection from any place at any time. This can be on the company LAN or from across the world. The computers still have to have a direct connection from the computer to the KVM Switch, but the user that is controlling the computers does not need to be directly connected to the KVM Switch. The Dominion KX3-864 is a KVM-over-IP switch that allows 8 users to control up to 64 servers via a TCP/IP network and one person can control at the rack.

Each of these main four types of KVM switches also needs to support a variety of platforms and technologies. For instance, KVM switches need to support different keyboard and mouse interfaces like PS/2, USB, Sun, Mac; and different video interfaces like VGA, DVI, ADC, HDMI, and display ports.  KVM switches also need to support different platforms such as Windows based PC/Servers, Mac, Sun, Linux, and more.  Computer interface modules (CIM) are available in a variety of formats in order to support these different video and input interfaces.

It’s clear to see that as applications and technologies evolved over the past three decades, they’ve required KVM switches to evolve and keep pace as well.  Fortunately, KVM technology is at a point where combinations are unlimited to accommodate the breadth of technologies used in server rooms and data centers. 


Schedule an online demo to see KVM switches in action and find out which switch fits best in your data center.