PURPOSE: To prevent mis-connection of a communication line and duplicated connection by setting an individual identificating signal to plural fixed stations, and allowing a mobile station to transmit the identificating signal to start an exchange of a fixed station.
CONSTITUTION: The identificating signal transmitted from a fixed station to a demodulator of a receiver of the mobile station is demodulated and inputted to an input terminal 7. Filters 9∼10 filter respectively the identificating signal of frequencies f1∼f3 corresponding to the modulation frequencies f1∼f3, the signal is detected by detectors 12∼14 and inputted to oscillators 16∼18. The oscillators 16∼18 transmit respectively signals of different modulation frequencies f1'∼f3' from the modulation frequencies f1∼f3 to an output terminal 20 respectively and the signals are used as modulation inputs to the transmitter of mobile station.
TSUBAKI ISAO
KIHARA TATSUROU
NIPPON TELEGRAPH & TELEPHONE
| JPS5136004A | 1976-03-26 |