A device comprising: a transmitter coupled to a first set of optical channels of an optical link, wherein the transmitter is adapted to operate in a first state to convert first electrical data signals to first optical data signals for transport over the optical link and operate in a second state to convert first electrical auxiliary signals to first optical auxiliary signals for transport over the optical link; a receiver coupled to a second set of optical channels of the optical link, wherein the receiver is adapted to operate in the first state to convert second optical data signals received over the optical link to second electrical data signals link and operate in the second state to convert second optical auxiliary signals received over the optical link to second electrical auxiliary signals; and a controller coupled to the transmitter and the receiver and adapted to monitor the first and second electrical auxiliary signals, characterized in that the controller is adapted to control the transmitter and the receiver to operate: in the first state when a first signal configuration represented by the combined states of the first and second electrical auxiliary signals is detected; and in the second state when a second signal configuration represented by the combined states of the first and second electrical auxiliary signals is detected; the first signal configuration comprises a first code, the first code corresponding to a first pattern of activated and deactivated optical channels of the first and second set of optical channels; the second signal configuration comprises a second code, the second code corresponding to a second pattern of activated and deactivated optical channels of the first and second set of optical channels; and the second code is different than the first code. a transmitter coupled to a first set of optical channels of an optical link, wherein the transmitter is adapted to operate in a first state to convert first electrical data signals to first optical data signals for transport over the optical link and operate in a second state to convert first electrical auxiliary signals to first optical auxiliary signals for transport over the optical link; a receiver coupled to a second set of optical channels of the optical link, wherein the receiver is adapted to operate in the first state to convert second optical data signals received over the optical link to second electrical data signals link and operate in the second state to convert second optical auxiliary signals received over the optical link to second electrical auxiliary signals; and a controller coupled to the transmitter and the receiver and adapted to monitor the first and second electrical auxiliary signals, characterized in that the controller is adapted to control the transmitter and the receiver to operate: in the first state when a first signal configuration represented by the combined states of the first and second electrical auxiliary signals is detected; and in the second state when a second signal configuration represented by the combined states of the first and second electrical auxiliary signals is detected; in the first state when a first signal configuration represented by the combined states of the first and second electrical auxiliary signals is detected; and in the second state when a second signal configuration represented by the combined states of the first and second electrical auxiliary signals is detected; the first signal configuration comprises a first code, the first code corresponding to a first pattern of activated and deactivated optical channels of the first and second set of optical channels; the second signal configuration comprises a second code, the second code corresponding to a second pattern of activated and deactivated optical channels of the first and second set of optical channels; and the second code is different than the first code. <EOS>