| 摘要 |
PROBLEM TO BE SOLVED: To provide a line connecting unit which can surely connect a telephone line and a radio channel to each other with high operability. SOLUTION: A line connecting unit 1 is provided with a two-wire/four-wire converting circuit 52, which connects a transmitting signal line 15 and a receiving signal line 16 connected to a semi-duplex or simplex type radio equipment and a two-wire telephone line 13 to each other and a transmission control signal generating circuit 24 which detects a transmitting signal TAF transmitted to the transmitting signal line 15 from the two-wire telephone line 13 and, at the same time, generates a transmission control signal SPTT for controlling the radio equipment to a transmitting state upon detecting the signal TAF. The transmission control signal generating circuit 24 detects a voice signal sent to the transmitting signal line 15, and at the same time, generates the transmission control signal SPTT upon detecting the voice signal. |
