ES335149A1 - Perfections in intercoms. (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

Improvements in interphones, characterized by being constituted by a wired central so that it admits secondary stations of different circuit; with only a microphone-loudspeaker translator and call button, as well as having these elements a switch to avoid listening to what is spoken in their vicinity without prior notice, having an anti-monitoring device equipped with a switch and alarm acoustic or optical; or a secondary station provided in addition to its microphone-loudspeaker translator of the call button and an optical indicator, of a rectifier to be operated from the central unit, said secondary stations being connected, always in equal connection strips, whatever the system of the secondary station, corresponding to each line a set of three switches, the first switching the corresponding line either to a pilot lamp, in series with a common acoustic signal to all of them, either to the inverter to talk or listen to the amplifier of the central station , giving, or not, ground to the second wire connected to the microphone-loudspeaker translator of the secondary station and the third switch giving, or not, voltage to a rectifier feeder of the amplifier of the exchange in alternative to terminals multiplied in the terminals of the different lines to give tension to your call buttons, in series with the pilot lights, also connecting the terminals of continuous voltage given by the rectifier to two other terminals of the strips of all lines to be used, or to act an acoustic warning connected in place of the microphone-speaker translator by a switch in secondary stations that do not want to be heard without warning, either giving mass to a supplementary rectifier that can act on other acoustic or optical warnings in the secondary station. (Machine-translation by Google Translate, not legally binding)