METHOD AND APPARATUS FOR USE IN SUPPLYING POWER OVER A TELEPHONE LINE

• US 20160330334A1
• Filed: 12/24/2014
• Published: 11/10/2016
• Est. Priority Date: 12/31/2013
• Status: Active Grant

• Current Assignee: British Telecommunications PLC (BT Group PLC)
• Original Assignee: British Telecommunications PLC (BT Group PLC)
• Inventors: COOPER, Ian Robert, HUMPHREY, Leslie Derek
• Granted Patent: US 10,110,755 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04M 19/08 with current supply sources at the substations generating ringing current H04M19/04
• CPC Class Codes: H04M 2201/80 line protection circuits such as current or overvoltage protection circuits

Abstract

A system comprising customer premises equipment including a reverse power supply unit and an access node to which the customer premises equipment is connected for permitting telephony devices connected to the customer premises equipment to make and receive telephone calls via the customer premises equipment and the access node. The reverse power supply unit is suitable for supplying electrical power from the customer'"'"'s premises to an access node via a twisted copper pair, the reverse power supply unit including a power consumption signature detector operable to detect if the power drawn from the reverse power supply unit corresponds to a signature power consumption pattern indicative of a telephony device being in or transitioning into an off-hook state when connected directly to the reverse power supply unit and not being connected via a current limiting interface.

Claims

1. A reverse power supply unit for supplying electrical power from a customer premises device to an access node via a twisted copper pair, the reverse power supply unit comprising:

a power consumption signature detector operable to detect if power drawn from the reverse power supply unit corresponds to a signature power consumption pattern indicative of a telephony device being in or transitioning into an off-hook state when connected directly to the reverse power supply unit and not being connected via a current limiting interface.

2. A reverse power supply unit according to claim 1 wherein detection of a rate of increase of current consumption above a predetermined threshold amount corresponds to detection of the signature power consumption pattern indicative of a telephony device being in or transitioning into an off-hook state when connected directly to the reverse power supply unit and not being connected via a current limiting interface.

3. A reverse power supply unit according to claim 1 wherein detection of a current consumption above a predetermined threshold, if occurring within a predetermined, finite start-up period from commencement of supplying of reverse power by the reverse power supply unit, corresponds to detection of the signature power consumption pattern indicative of a telephony device being in or transitioning into an off-hook state when connected directly to the reverse power supply unit and not being connected via a current limiting interface.

4. A reverse power supply unit according to claim 1 wherein the current limiting device comprises a capacitor arrangement for limiting the amount of direct current passed through the current limiting interface.

5. A reverse power supply unit according to claim 4 wherein the current limiting interface is incorporated into either a dongle or a device for fitting in a master socket of a user'"'"'s premises.

6. Customer premises equipment including a reverse power supply unit according to claim 1, and further comprising:

a current limit arrangement connected to a customer premises wiring for limiting at least one of the amount of current or the maximum rate of increase of current which can be drawn by a telephony device connected to the customer premises wiring to be no greater than a predetermined amount or rate, the customer premises wiring being connected to the twisted copper pair in such a manner that voice signals can be transmitted from the telephony device to an access node to which the twisted pair is connected.

7. An access network unit for use with the reverse power supply unit of claim 1 comprising:

a rate of change of current limitation device, wherein the rate of change of current limitation device has one or more of the following properties;

a maximum rate of change of current draw of less than 150 mA/s when connected to a 50V dc power supply; and

the inclusion of a gyrator for performing the rate of change of current limitation providing a predetermined inductance in order to provide a predetermined maximum rate of change of current draw when increasing its power consumption from a specified dc power source.

8. A reverse power supply unit according to claim 5 wherein the current limiting interface is incorporated into an interstitial plate.

9. An access network unit for use with the customer premises equipment of claim 6 comprising:

a rate of change of current limitation device, wherein the rate of change of current limitation device has one or more of the following properties;

a maximum rate of change of current draw of less than 150mA/s when connected to a 50V dc power supply; and

the inclusion of a gyrator for performing the rate of change of current limitation providing a predetermined inductance in order to provide a predetermined maximum rate of change of current draw when increasing its power consumption from a specified dc power source.