The LonTalk protocol was designed to operate over any type of media.
The Neuron chip provides a flexible hardware interface to facilitate the connection to a wide variety of transceiver types.
You can get transceivers that allow you to communicate over twisted pair, free topology twisted pair (FTT), radio frequency (RF), power line communications (PLC), coaxial cable etc. You can even design your own transceiver.
The twisted pair, the free topology and the power line are available from Echelon. Other media types are available from other third party companies, or you can develop your own if you like.
The decision on which media type is used is usually based on a number of criteria such as industry standards, bandwidth, distance, number of devices etc.