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US 4,103,114 AGranted
Variable delay ringing detector
AssigneeBell Telephone Laboratories, Incorporated
InventorBarry Sheldon Bosik
Life of this patent
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Abstract
A variable delay ringing detector in a single channel carrier system for telephone service is disclosed including at the remote terminal a battery charger for charging a battery which powers the carrier electronics at the remote terminal. A ringing generator and supervisory circuits are disclosed to provide normal telephone supervision on the carrier-derived channel. The variable delay ringing detector includes two capacitors which are charged in response to ringing current.
Claims2
A variable delay ringing detector comprising
- switching means responsive to ringing signals for supplying a charging current,
- a first capacitor connected to receive said charging current directly,
- a second capacitor connected to receive said charging current through a unilateral conducting device,
- a high impedance discharge path for said second capacitor, and
- a ringing threshold detector responsive to the voltage on said first capacitor for indicating the presence of ringing signals.
2 more elements
Dependencies are inferred from the claim text.