Patent ID: 7539413

Claim:
An observation apparatus which performs prescribed observation and notifies a management apparatus of an observation result, the observation apparatus comprising: a signal reception part to receive a signal transmitted from the management apparatus; an observation signal generation part to perform the prescribed observation and to generate an observation signal indicating the observation result; a signal modulation part to modulate the signal received by the signal reception part, by using the observation signal generated by the observation signal generation part; and a signal transmission part to return the signal modulated by the signal modulation part to the management apparatus, wherein: the signal reception part receives the signal transmitted from the management apparatus through a first transmission line connected to the management apparatus; the signal transmission part returns the signal modulated by the signal modulation part to the management apparatus through a second transmission line connected to the management apparatus; the observation apparatus is one of a plurality of observation apparatuses cascadingly connected to the management apparatus through the first transmission line and the second transmission line; the signal reception part separates a signal which is to be received, from a multiplexed signal transmitted from the management apparatus through the first transmission line and made by multiplexing a plurality of signals for a plurality of observation apparatuses, and receives the signal separated; the signal modulation part modulates the signal separated and received by the signal reception part, by using the observation signal; and the signal transmission part multiplexes the signal modulated by the signal modulation part and a signal of other observation apparatus, which is communicated through the second transmission line, and returns a multiplexed signal to the management apparatus through the second transmission line.