Ternary physical protocol for MARILAN, a multiple-access ring local area network

A design is presented for an asynchronous ternary transmission physical-layer protocol for a multiple-access-ring local area network (MARILAN) that uses the PLAYTHROUGH data-link-layer protocol. The ternary encoding scheme presented provides for both bit synchronization and simultaneous information transfer on a single pair of wires without increase in hardware complexity or bandwidth requirements. Bandwidth requirements for the polar return-to-zero (RZ) scheme proposed previously for single-pair wire links and the ternary non-RZ (NRZ) scheme used here are analyzed and compared to each other and to requirements for the binary Manchester code. Test results on prototype ring interface units using this ternary transmission mechanism are presented. Several advantages that accrue from the use of ternary NRZ signaling on the links of the ring are discussed.<>