Telephone substation apparatus for generating multifrequency signals

摘要: A multifrequency signalling arrangement for a subscriber telephone set or other substation circuit. In this resonant circuit, comprising pair of tapped inductors and associated capacitors, is connected in parallel with an amplifier, which forms part oscillator, through late-break contacts mechanically linked to each digit button on the selector pad. During initial period travel selected early-make contacts, also buttons, simultaneously enable amplifier energize At later separate interrupt flow direct current circuit thereby initiate oscillations said at frequency are supported by yet enabled transmitted central office.