Appletalk is a protocol developed by Apple to handle networking with little to no configuration (you may be sensing a pattern here). It reached its peak in the late 80s and early 90s, but there are still some devices that utilize this protocol. Most of its core technology has been moved over to Bonjour, while UPnP (Universal Plug and Play) has picked up on its ideology and moved the concept forward across many different hardware and software packages.