I'd say they call them KVM switches (KeyboardVideoMouse) and some even switch sound.
I have used one with pc keyboard adapter and it worked nice, you 'doublepress' ctrl to switch. the only problem was that it couldnt connect PC using digital..
got me thinking, since some DVI connectors can carry both analog and digital, in principle you might connect at the same time PC (digital) and Amiga (analogue) with simple Y cable, right? to switch to amiga, simply turn off PC..
