Patent ID: 7680466

Claim:
A communication device, comprising, in a casing: a modulation/demodulation unit having a modulating function for modulating and converting an input baseband signal into an intermediate frequency signal, and a demodulating function for demodulating and converting an intermediate frequency signal into a baseband signal; transmission/reception units of an active transmission system and a standby transmission system, each of which has a transmitting function for converting an intermediate frequency signal from the modulation/demodulation unit into a radio frequency signal and supplying it to an antenna, and a function of converting a radio frequency signal into an intermediate frequency signal and outputting it to the modulation/demodulation unit; a branching unit for separating a desired radio frequency from an allocated radio frequency and performing provision and reception of a signal with the transmission/reception units; and a line switching and monitor control unit having a line switching function for performing line switching between the active transmission system and the standby transmission system, a line control function for monitoring a line and controlling a switching operation of a line switching part corresponding to a monitored state, and a monitoring function for monitoring and displaying a state of an apparatus, wherein the modulation/demodulation unit and the line switching and monitor control unit, commonly used in the active transmission system and the standby transmission system, are incorporated in a lower part of the casing, the transmission/reception units of the active transmission system and the standby transmission system and the branching unit are incorporated in an upper part of the casing, and the transmission/reception units of the active transmission system and the standby transmission system and the branching unit are arranged in parallel such that the branching unit is positioned at a center thereof, thereby preventing characteristics of the branching unit from being changed by heat generated by the transmission/reception units.