This little nifty (outdated) box enables the user to connect one keyboard to two PC's. The switching is done by pressing the pause key twice. It is of an age as PC's had PS2 keyboards. Of course now a days there are better solutions that use LAN or WiFi (Synergy). In addition, a little "hot-key-keyboard" can be connected to the extender. The twelve keys can be programmed with any strings. The two shift modes give you 36 hot-keys.