If your keyboard or mouse uses a ps2 in order to connect to your computer, then you are going to need a ps2 kvm. In other words, a computer that uses the ps2 interfaces will only connect to a kvm switch with ps2 cables. Any kvm switch can be considered a ps2 kvm if it has ps2 cables which can connect to your server or workstation. Many types of kvm switches support the ps2 interface, including kvm matrix switches, ip kvm and kvm with audio.
With a 4 port kvm that has ps2 cables you can control up to four computers with a single ps2 mouse and keyboard. This enables you to clean up a lot of that cable clutter around your servers and workstations. Almost all kvm manufacturers carry a complete line of ps2 supported switches and with technology moving so fast, today even the usb kvm can be as readily found and as easy to use as the ps2 kvm.