To eliminate illegal telephone charge forging by a connecting a normal telephone set to a radio equipment being communication possible with a base station by transmitting a dial signal from a second input part to the base station, forming a radio line with the base station and transmitting a voice signal from the input part to the base station.

A public telephone terminal is connected to a radio equipment 2 by a voice line 3 and a data line 4. The voice line 3 connects the telephone line 14 of the public telephone terminal 1 to the RJ 11 interface 21 of the radio equipment 2 and an analog signal is permitted to flow in accordance with the telephone line. The data line 4 connects the control circuit 15 of the public telephone terminal 1 to the RS-232 C interface 24 of the radio equipment 2 and a digital signal is permitted flow. Then, the dial signal is permitted to flow in the data line 4. That is, the dial signal inputted by the ten-keys 11 of the public telephone terminal 1 is transmitted to the control circuit 23 of the radio equipment 2 with the data line 4 and the RS-232 C interface 24 as the digital signal.