Patent ID: 8306068

Claim:
A system for transmitting data using a network carrying an AC current, comprising: a timing signal source periodically transmitting phase-coded timing signals comprising one or more phase-coded timing signal symbols and using voltage of the AC current to generate time markers used to determine when each phase-coded timing signal symbol is transmitted and to phase-code each timing signal symbol; a plurality of numbered slave units, each numbered slave unit receiving at least one phase-coded timing signal and using voltage of the AC current to generate time markers used to determine when each phase-coded timing signal symbol is received and to decode each phase-coded timing signal symbol, each numbered slave unit transmitting a data signal using its number and time when a timing signal is received to determine when to begin transmitting so that data signals from the slave units do not overlap with each other or with the timing signals; and a main unit receiving the data signals from the slave units.