A 140 Mbit/s optical fibre digital line system employing a 5B6B line code with extended auxiliary channel capacity

A 140 Mbit/s optical line system is proposed which will not only satisfy the emerging tie line requirement but which will also be capable of adaptation for long haul systems to allow replacement of the older equipment. Results from prototype testing have shown that all of the design parameters for both the line code and the remainder of the system have been achieved with adequate margins