Abstract: A network element for use in a multi-protocol WDM network, the network element comprising a rate multiplying encoding unit for applying a rate multiplying line code to an electrical transmit data signal prior to conversion of the electrical transmit data signal into an optical WDM channel data signal, a rate dividing decoding unit for applying a corresponding rate dividing line code to an electrical receive data signal converted from a received optical WDM channel data signal, and a management unit arranged, in use, to generate an embedded operational channel (EOC) signal in a portion of a bandwidth of the WDM channel for transmission of network management data, wherein the encoding unit is arranged such that, in use, the rate multiplying line code is not applied if the electrical transmit data signal is of a protocol satisfying a threshold condition and is applied if the electrical transmit data signal is of a protocol not satisfying the threshold condition, wherein the decoding unit is arranged such that, i