In one embodiment, an optical device comprising an emitter, first and second emitter optical elements and a receiver is disclosed. A protective conductive layer such as a metal silicide is then formed over the contact area in situ. The characteristic includes an overall rate change value that specifies a ratio of an input to an output sample rate. The inkjet printer mounts the inkjet head. to select the lowest power setting for which the signaling system provides some minimum communication bandwidth without exceeding a desired bit-error rate. At a receiver, the virtual channel table transmitted from the transmitting side is parsed, thereby determining whether the current received channel is an active or inactive channel.