5B6B optical fibre line code bearing auxiliary signals

A variation of the 5B6B line code is proposed which allows the insertion of an ancillary channel with a capacity of about 0.6% of primary channel capacity. It does not deteriorate line code properties nor primary channel performance. A code list is proposed as well as basic hardware. The properties of the ancillary channel are discussed and a possible design for the insertion of multiplexed data and Δ M vice signals is outlined