Patent ID: 7783042
Filing Date: 2010-08-24
Classification: H04L

Abstract:
1. A communication system comprising first and second communication devices, which are connected to each other through at least one transmission line including first and second channels through which a signal in a state where optical power is relatively small and a signal in a normal state where optical power is relatively large are transmitted, the communication system further comprising: a reference signal generator for generating a reference signal to be transmitted through the second channel; a communicating section for transmitting the reference signal from the first communication device to the second communication device through the first channel, in the normal state where the optical power is relatively large; a phase comparator for comparing a phase of the reference signal detected from the first channel with a phase of the reference signal detected from the second channel, in each of the first and second communication devices; and a synchronization establishing section for establishing synchronization between the first and second communication devices, based on a result of comparison made by the phase comparator.