Ringing detector for telephone circuits
AssigneeMagnetic Controls Company
InventorCordell V. Castleman
Life of this patent
Estimating the term…
Abstract
A circuit for detecting ringing signals on a telephone line in which the alternating voltage oscillations are converted to direct current pulses which are used to charge a first capacitor. Only signals of 14 hertz or above are sufficient to repetitively charge the first capacitor to a high enough voltage to open continuously a grounding circuit through a comparator, thus, allowing a second capacitor to charge up and open a second grounding circuit thus permitting current to flow to a suitable output. The output is used to activate lights on the telephone which lights are either flashed or winked by a unique resistance balanced solid state flash or wink generator.
Claims3
A ringing detector circuit for use in telephone systems comprising:
- receiving means adapted to connect to the phone lines and operable to convert the alternating current ringing signal from the lines to a series of direct current pulses;
- first charge storing means connected to receive the pulses from the receiving means and further connected to discharge through a predetermind resistance at a comparatively slow rate, so as to require a sufficiently high frequency of pulses in order to maintain a first selected voltage;
- second charge storing means connected to a source of voltage so as to be charged thereby;
- first switching means connected to said first and second storing means and operable to discharge the second charge storing means when in a first condition and to not discharge said second storing means when in a second condition, said first switching means operable to switch from said first condition to said second condition in response to the reception of said first selected voltage stored by said first storing means;
- and
- second switching means connected to said second storing means and to an indicating means, the second switching means operable to activate the indicating means in response to the reception of a second selected voltage stored in said second storing means.
Dependencies are inferred from the claim text.