LocalTalk is a particular implementation of the physical layer of the AppleTalk networking system from Apple Computer.
Farallon's competing PhoneNet transceiver
Image: Apple Local Talk box interior 1
Image: Apple Local Talk box interior 2 auto termination switch
AppleTalk is a discontinued proprietary suite of networking protocols developed by Apple Computer for their Macintosh computers. AppleTalk includes a number of features that allow local area networks to be connected with no prior setup or the need for a centralized router or server of any sort. Connected AppleTalk-equipped systems automatically assign addresses, update the distributed namespace, and configure any required inter-networking routing.
Farallon PhoneNET adapter
Image: Apple Local Talk box interior 1
Image: Apple Local Talk box interior 2 auto termination switch