# US 8,787,562 B2 · Method and system for providing DC power on local telephone lines

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- Number: US 8,787,562 B2
- Document ID: US8787562B2
- Status: Granted
- Kind: B2
- Application number: 11/640,300
- Filed: 2006-12-18
- Published: 2007-06-07
- Granted: 2014-07-22
- Earliest claimed: 2003-01-30
- Assignees: Conversant Intellectual Property Management Inc.
- Applicants: Yehuda Binder; Ami Hazani; Semion Kofman
- Inventors: Yehuda Binder; Ami Hazani; Semion Kofman
- Web page: https://patentgrep.com/patent/US8787562B2

## CPC

- H04M 19/08: with current supply sources at the substations (generating ringing current H04M19/04)
- H04M 9/08: Two-way loud-speaking telephone systems with means for conditioning the signal, e.g. for suppressing echoes for one or both directions of traffic
- H04M: TELEPHONIC COMMUNICATION (circuits for controlling other apparatus via a telephone cable and not involving telephone switching apparatus G08)

## Abstract

A telephone unit device connectable in series between a telephone set and a wire pair coupled to a telephone service and carrying DC power and an AC telephone signal. The device includes: a first connector connectable to the wire pair; a second connector connectable to the telephone set; means connected between the first and second connectors for passing substantially without change the AC telephone signal between the wire pair and the telephone set; and means connected between the first and second connectors for receiving DC power only from the wire pair and converting the DC power to a level suitable for proper telephone operation of the telephone set connected thereto.

## Claims

### Claim 1

A telephone unit device connectable in series between an analog telephone set and a wire pair coupled to a telephone service and carrying DC power and an analog telephone signal, said device comprising: a first connector connectable to the wire pair; a second connector connectable to the telephone set; a signal passing circuit connected between said first and second connectors for passing substantially without change the analog telephone signal between the wire pair and the analog telephone set; and a DC/DC converter connected in series between said first and second connectors for receiving DC power only from the wire pair and converting the DC power to a level suitable for proper telephone operation of the analog telephone set connected thereto
wherein:
said signal passing circuit comprises a transformer composed of a primary winding and a secondary winding and first and second capacitors, each said capacitor being connected in series with a respective one of said windings; and
said DC\DC converter is connected between said first and second capacitors.

### Claim 2 (depends on 1)

The device of claim 1 integrated into one of: an analog telephone set; and a telephone outlet.

### Claim 3 (depends on 1)

An outlet comprising the telephone unit device of claim 1.

### Claim 4 (depends on 1)

The device of claim 1 in combination with:
an off-hook detector couplable to the analog telephone set for detecting an off-hook condition of the analog telephone set;
an off-hook transmitter coupled to said off-hook detector and to the wire pair for supplying an off-hook indication to the wire pair in response to detection of an off-hook condition by said off-hook detector.

### Claim 5 (depends on 4)

The device of claim 4, wherein the off-hook indication is a signal composed of one or more tones.

### Claim 6 (depends on 4)

The device of claim 4, wherein said off-hook indication is provided by a variable impedance that assumes a selected value to produce the off-hook indication.

### Claim 7 (depends on 4)

The device of claim 4, wherein the off-hook indication is a message sent over a data communication network.

### Claim 8 (depends on 7)

The device of claim 7, wherein the data communication network uses the wire pair as a communication medium.

### Claim 9 (depends on 1)

The device of claim 1, wherein:
each of said primary and secondary windings has a center tap; and
each of said first and second capacitors is connected to the center tap of a respective one of said primary and secondary windings.

### Claim 10 (depends on 1)

The device of claim 1, wherein the telephone set is connectable to only said second connector.