Floating digital loop carrier telephone interface

US5566239A · kind A · utility

Assignee

• Teltrend, Inc. · US

Inventors

• Frank X. Garcia · Aurora, US
• Van Hung NGUYEN · Sindelfingen, DE

Key dates

• Filing date: Jun 7, 1994
• Grant date: Oct 15, 1996
• Expiry date: Jun 7, 2014

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04Q11/04
• WIPO field: Telecommunications
• WIPO sector: Electrical engineering

Abstract

A digital loop carrier system that more conveniently passes a flash-hook signal while still allowing open-switching-intervals (loop current feed open intervals) with a floating ground central office switch interface. The carrier system includes both an office loop and a customer loop. The interface includes both an office loop switch and controller. The controller regulates the operation of the switch and also regulates whether the customer loop should be open or closed. When the office loop is not grounded, but current was detected by the controller in the office loop prior to the controller opening the office loop, the controller waits a predetermined interval after opening the office loop before opening the customer loop and terminating the call.