Point to Multipoint radiotelephone system

摘要

A radiotelephone system comprises plural sub units, and a main unit for communicating with the plural sub units. The main unit of the radiotelephone system comprises a first transmitter for transmitting radio signals to the sub units, a first receiver for receiving radio signals from the sub units, chief sub unit determining means for determining the chief sub unit to make radio communications out of the plural sub units, and first communication establishing means for establishing the communications with the chief sub unit determined by the chief sub unit determining means by controlling the first transmitter and second receiver. The sub unit of the radiotelephone system comprises second transmitting means for transmitting radio signals to the main unit, second receiving means for receiving radio signals from the main unit, and second communication establishing means for controlling the second transmitting means and second receiving means so as to establish radio communications with the main unit when selected as the chief sub unit, or controlling the second receiving means so as to receive the radio communications between the main unit and the chief sub unit when not selected as the chief sub unit.