PURPOSE: To conduct an operating test externally without opening a cover of a housing by providing a test switch means for leaking a control signal operably from the external part of the case.

CONSTITUTION: In conducting a connecting and operating test between a base station 16 and a radiotelephone set U, when test switch circuits 20, 21 are turned on, a control signal from the base station 16 among control signals transmitted and received between the radiotelephone set U and the station 16 is leaked to a line 10 via the switch circuit 20 and a control signal transmitted from the radiotelephone set U to the base station 16 is leaked to a line 11 via the switch circuit 21, respectively. Thus, in observing the transmitting and receiving states of the control signal by, e.g., a synchroscope, it is satisfactory to connect its probe between both terminals of a receiver 12 or between both terminals of a transmitter 13, and the test work is conducted easily without opening the cover of the case 9 of the radiotelephone set U.