| 摘要 |
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.
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