David N Hurst

US Patent:

55398057, Jul 23, 1996

Filed:

Sep 21, 1994

Appl. No.:

8/310245

Inventors:

Mike Bushue - Belmont CA
Steve Cartier - San Jose CA
Craig A. Lindahl - Mountain View CA
David Hurst - San Ramon CA

Assignee:

Raynet Corporation - Menlo Park CA

International Classification:

H04M 124
H04M 100
H04M 960
H04M 908

US Classification:

379361

Abstract:

A voltage detection circuit, in conjunction with a power supply system for ringing voltage generation in a remote telecommunications unit, monitors the operating voltage level of the remote unit and, when an undervoltage condition is detected, causes a ringing reference-signal generator to collapse the reference (AC) sine wave into a fixed (DC) state and holds it in this state for a preselected time, thereby substantially reducing the ringing-signal current load and allowing the operating voltage level to restore. The features of the invention allow for continued processing of calls in progress and for incoming call completion during an undervoltage condition. The increased reliability and integrity of the power supply system allows for extended power supply feeder distance to the remote telecommunications unit.

US Patent:

53215966, Jun 14, 1994

Filed:

May 17, 1993

Appl. No.:

8/059484

Inventors:

David E. Hurst - San Ramon CA

Assignee:

Raynet Corporation - Menlo Park CA

International Classification:

H02M 748

US Classification:

363 8

Abstract:

A DC to DC switch mode power supply for a service subscriber interface unit of a fiber optic network includes a source of DC primary power, a main DC to DC switched mode power supply connected to the source of DC primary power and including switching circuitry and rectifier circuitry for supplying DC operating power to the service subscriber interface unit including central office battery power to at least one subscriber loop connected thereto, and a ringing voltage DC to AC switched mode generator connected to the source of DC primary power and including switching circuitry and synchronous rectification circuitry for generating ringing ringing voltage approximating a sine wave supplied as a reference to the synchronous rectification circuitry. A Johnson counter and resistor capacitor network is preferably employed to convert a reference ringing square wave into a sine wave.