Packet transmission system and a terminal apparatus

摘要

A packet transmission system is disclosed. The system serves between terminal apparatuses that include a supervisory control circuit configured to transmit a supervisory signal in a direction opposite to the transmission direction of a main signal on each of and both of an upstream circuit and a downstream circuit. The packet transmission system transmits overhead information of a packet frame of the main signal of the upstream circuit and the downstream circuit using the supervisory control circuit of the downstream circuit and the upstream circuit, respectively.