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:
Jul. 07, 1998
Filed:
Mar. 19, 1997
Tim Urry Price, Salt Lake City, UT (US);
Daniel Paul Petersen, Taylorsville, UT (US);
U.S. Robotics Mobile Communications Corp., Salt Lake City, UT (US);
Abstract
A novel line-current protection circuit and method that is useable with a PCMCIA modem card is disclosed. The protection circuit is adapted to detect when an excessive voltage is present across the tip and the ring leads of a telephone subscriber loop by sensing the amount of line-current being supplied to line interface circuitry disposed on the PCMCIA modem card. The protection circuit includes a current sensing circuit portion that is placed in series with the tip lead and which detects when the line current exceeds a predetermined maximum amount. In the event the line current exceeds the maximum, the current sensing circuit asserts an excessive line current signal. A control and delay circuit causes the relay circuit to open the electrical connection between the modem and the telephone line only when the line current exceeds a predetermined maximum amount for a minimum amount of time. The protection circuit also includes a backup fuse, which will trip if the primary components of the protection circuit fail.