Citophonic installation that works with only two current threads between a main position and various derivations. (Machine-translation by Google Translate, not legally binding)

摘要

A cytoponic installation that works with only two common wires between a main station and several branches, characterized by the fact that the call of the derivatives comes about by means of a calibrated dc voltage, relative to each one of the users in particular, and because such voltage acts so that the current of the call that drives the buzzer or the sonar of the derivative, is sent from a source of energy located near the derivative itself, while the transmission circuit for the different voltage values according to the the user button operated, comprises a differential amplifier, transistor, diodes, two zaner diodes, a capacitor, resistors and also a series of further resistors connected to the call buttons. (Machine-translation by Google Translate, not legally binding)