The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 01, 1982
Filed:
Dec. 13, 1979
Paul C Davis, Reading, PA (US);
Raymond G Jackson, Indianapolis, IN (US);
Kenneth F Sodomsky, Reading, PA (US);
Dennis L Whitson, Blue River Township, Hancock County, IN (US);
Bell Telephone Laboratories, Incorporated, Murray Hill, NJ (US);
Abstract
In a subscriber telephone set, an active speech network provides a sidetone signal and for equalization of the transmit and receive signals at the tip and ring line port and also maintains the dc voltage at a substantially constant level at this port. The network is compatible with conventional telephone sets and operation on long loops in parallel with such sets is provided for. Internal circuitry (320) within the network check both loop current and tip-to-ring voltage to ensure that both are of a magnitude sufficient for a tone signaling dial (301) to properly generate tone signals before enabling the dial.