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:
Sep. 21, 1999
Filed:
Jun. 20, 1997
Merle L Miller, Austin, TX (US);
Advanced Micro Devices, Inc., Austin, TX (US);
Abstract
A system and method for performing diagnostic leakage impedance testing at the subscriber line interface utilizing portions of existing circuitry designated for driving current on the telephone line during normal operation is provided. The diagnostic apparatus is used with a telephone line drive system having a tip-line current-mode amplifier for driving current on the tip line and a ring-line current-mode amplifier for driving current on the ring line during normal operation. A control signal generator generates voltage control signals corresponding to desired subscriber loop voltage characteristics. A voltage sense circuit compares the voltage control signals to actual subscriber loop voltage characteristics resulting from driving the current on the subscriber loop. The current driven onto the subscriber loop is adjusted accordingly. A processor receives an indication of a current level of the current driven onto the subscriber loop, and calculates the leakage impedances on the subscriber loop in response to the current level and the voltage control signals.