PURPOSE:To reduce greatly the power consumption of the channel display unit, by giving the blinking to the luminous body of the channel display unit. CONSTITUTION:The voltage applied to power terminal PS is supplied to one of LEDD1-D3 via resistance R1 and switch S2c when transistor TR1 conducts. The output of receiving multivibrator 9 is connected to the base of TR1 via switch S1b and resistance R4 at the receiving time; while the output transmitting multivibrator 10 is connected in the same way to the base of TR1 at the transmitting time. The outputs of multivibrators 9 and 10 give alternately the conduction and the nonconduction to TR1, and the LED selected by switch S2c interlocking channel switching switches S2a and S2b each repeats the blinking. Furthermore, the different oscillation frequencies are given to multivibrators 9 and 10, and thus the decision becomes possible at both the receiving time and the transmitting time.