The frequency mulplex in adjacent cell is realized using the present invention.

At the base station, the various telephone channels are processed as a frequency-multiplexed signal.

Thus different frequency multiplexing strategies for different connection types are realized, and the usage ratio of the frequency spectrum is improved while suppressing the same frequency interference.

The reception section has a configuration capable of receiving the signal state of the frequency multiplex signal from a counter station.

The transmission section has a configuration capable of transmitting the frequency multiplex signal by a plurality of demodulation systems.

The master site and a remote site then conduct communications therebetween by frequency-hopping and/or orthogonal frequency multiplexing among the clear channels using an a priori known PN sequence.

The NICAM sound carrier is therefore recorded in a deeper layer (S2) with second magnetic heads (K2) in frequency multiplex with EM sound carriers (T1, T2) at lower frequency.

For transmission of signalling and control commands, the system includes a special organization channel which is also integrated in the frequency-multiplexed signal.

Frequency multiplexing is used in different directions along the single fiber in order to eliminate noise due to reflections along the optical path.