PURPOSE: To surely recognize which of plural speech channels is an idle channel at the time of calling by providing a memory storing an operating channel of other station to the equipment and sensing a carrier from other channel than the operating channel.

CONSTITUTION: When the radio equipment is in the standby state, a microcomputer 5 matches a communication frequency of a receiver 2 and a transmitter 3 with a frequency of a communicating channel with a frequency of a control exclusive channel and discriminates whether or not a signal is a signal used to call its own station or other station among control signals via an antenna 1, the receiver 2 and a modem 4. When the signal is a signal used to call its own station, the state transits to the communication state, and when the signal is a signal used to call other station, channel information in the signal is stored in an operating channel memory 7. When its own station makes calling, the memory 7 is referenced and the computer 5 applies frequency control of the receiver while avoiding the operating channel. Then a carrier through plural speech channels is sequentially sensed to detect an idle channel. Thus, which of plural speech channels is an idle channel at calling is surely recognized.