Radio communication system enabling multiplex communication

A radio communication system enabling multiplex communication, comprising:

• a master radio set including:
• a main radio set carrying out long-range radio communication,
• a master communication unit carrying out wired communication for allowing voice signals to be transmitted/received to/from the main radio set,
• a master transmitter to which voice signals are input,
• a master receiver outputting voice signals, and
• a master controller for controlling the master communication according to on or off state of a PTT switch;
• a plurality of subsidiary radio sets, each including:
• a subsidiary communication unit carrying out short-range radio communication for allowing voice signals to be transmitted/received to/from the master communication unit,
• a subsidiary transmitter to which voice signals are input,
• a subsidiary receiver outputting voice signals, and
• a subsidiary controller carrying out a control function in such a way that, when the subsidiary radio sets go outside a coverage area available for communication with the master radio set and lose radio communication, any one of the subsidiary radio sets with radio communication disconnected can be changed to a slave master radio set;
• and
• a connection unit connecting the main radio set and the master radio set to each other to transmit and receive voice signals, and provided with the PTT switch to carry out a control function to transmit and receive voice signals in a PTT method.