Signalling system

(57) A summary signal transmission-and-reception system is offered, and it can be used for it updating the prices of the goods electrically displayed on the shelf (1) of a supermarket. A signal transmission-and-reception system is equipped with the 1st signal transmission-and-reception equipment, and it, The input terminal which receives electric message information from a central computer system (5), The spectrum spread modulator which modulates the received message information, and the modulated data are changed into a corresponding audible signal, and it has an electroacoustic transducer (11) which transmits the audible signal to a transmission media. Further, a signal transmission-and-reception system is equipped with the 2nd signal transmission-and-reception equipment (3), and it, A means to receive an audible signal from the above-mentioned transmission media, and to change the received audible signal into a corresponding electrical signal, It has a spectrum spread demodulator which restores to the received signal, and a message regeneration machine which carries out regeneration of the message information transmitted by the 1st signal transmission-and-reception equipment from the signal outputted by the demodulator.