Underground information communication system and related manhole cover

摘要

A manhole cover is provided with an incorporated radio repeater and a repeater antenna attached onto its rear surface. Another repeater antenna is provided inside the sewer below the manhole. This repeater antenna is connected to a radio transmitter/receiver, an electric-optical/optical-electric signal converter, and an optical fiber cable. With this arrangement, the manhole cover and optical fiber cable are connected via radio communication.