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:
Oct. 09, 2001
Filed:
May. 29, 1998
Robert K. Chen, North Andover, MA (US);
Dieter J. H. Knollman, Arvada, CO (US);
Avaya Technology Corp., Miami Lakes, FL (US);
Abstract
A dual-supply line-interface circuit (,) uses a −48V power supply (V,) to drive long subscriber loops (,) and uses a −28V power supply (V,) to drive short subscriber loops. For intermediate-length loops, a dual-slope current-feed profile (FIG.,) is employed to limit the line-circuit's power dissipation. The line-interface circuit operates in an apparent constant-current mode, generating about 40 mA of differential line current using the low power supply, up to a threshold line voltage of about 25V, which is equal to the low power supply voltage minus required overhead. For longer loops, the line-interface circuit switches to a second constant-current mode, generating about 22 mA of differential current using the high power supply, which maintains the loop current constant until it drops to the 48V resistive-feed value.