# US 8,787,539 B2 · Method and device for coupling a DC supply line to a telephone line or coaxial cable > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,787,539 B2 - Document ID: US8787539B2 - Status: Granted - Kind: B2 - Application number: 14/001,886 - Filed: 2012-03-01 - Published: 2014-02-06 - Granted: 2014-07-22 - Earliest claimed: 2011-03-01 - Assignees: A Tlc S.R.L. - Applicants: Stefano Marchetti - Inventors: Stefano Marchetti - Web page: https://patentgrep.com/patent/US8787539B2 ## CPC - H04B 3/56: Circuits for coupling, blocking, or by-passing of signals - H04B 3/02: Details - H04L 12/10: Current supply arrangements - H04L 25/0282: {Provision for current-mode coupling} - H04B: TRANSMISSION - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A coupling device that implements a related method for remote powering wide band digital telecommunication devices through telephone lines or coaxial cables installed in all buildings, has an AC blocking transistor inserted in the electrical path from a voltage supply line to the telephone line or coaxial cable. The transistor has a first current terminal coupled to the supply line and a second current terminal coupled to the telephone line, and it is controlled with a DC control voltage such to keep it in a substantially linear functioning condition at the edge of a saturation condition during the normal functioning whatever the supply current that flows through the transistor is, destined to the connected telecommunication devices. This may be done by properly generating this control voltage by means of a dedicated voltage generator, or by nullifying the DC component of the difference of potential between the control terminal and the second current terminal, for example through a low-pass filter that generates the voltage on the control terminal as a low-pass replica of the voltage on the second current terminal. ## Claims ### Claim 1 A coupling device of a DC power supply line to a telephone line or coaxial cable, said coupling device having a first connection pad to a DC power supply line and a second connection pad to a telephone line or coaxial cable adapted to provide a DC voltage and a DC supply current to at least a telecommunication device connected thereto, said coupling device having an electrical path, defined between said first pad and said second pad, adapted to be crossed by said DC supply current, at least an AC blocking transistor inserted in said electrical path, having a first current terminal functionally coupled to said first pad and a second current terminal functionally coupled to said second pad; a control circuit connected between said second current terminal and a control terminal of said AC blocking transistor, adapted to generate a DC control voltage of the AC blocking transistor to keep it in a linear functioning condition at the edge of a saturation functioning condition when the DC supply current flows through the AC blocking transistor, wherein said control circuit is a low-pass filter adapted to generate said control voltage as a low-pass replica of the voltage on said second current terminal. ### Claim 2 (depends on 1) The coupling device of claim 1, further comprising an inductor, inserted in said electrical path, connected between said second current terminal and said second connection pad. ### Claim 3 (depends on 1) The coupling device according to claim 1, wherein said AC blocking transistor is a MOSFET or a BJT, of N-type or of P-type. ### Claim 4 (depends on 1) A device for injecting a DC supply current in a telephone line, comprising: a transceiver adapted to transmit/receive signals of digital data; a circuit for delivering a supply current (PSE), functionally connected to at least an electrical path, adapted to inject the DC supply current therethrough; a coupling device according to claim 1 functionally inserted in said electrical path. ### Claim 5 (depends on 1) A device for drawing a DC supply current from a telephone line, comprising: a transceiver adapted to transmit/receive signals of digital data; an internal powering circuit for drawing said DC supply current, functionally connected to at least an electrical path to be crossed by the DC supply current flowing therethrough and adapted to provide a voltage and a current for powering the device for drawing; a coupling device according to claim 1 functionally inserted in said at least one electrical path. ### Claim 6 (depends on 5) The device for drawing a DC supply current according to claim 5, wherein said transceiver is adapted to communications between a xDSL line coupled to said telephone line and a GPON communication; further comprising a phone interface FXO adapted to process POTS signals coming from an interface PSTN, adapted to transcode said POTS signals towards said transceiver. ### Claim 7 (depends on 4) The device for injecting a DC supply current according to claim 4, wherein said telephone line is a twisted pair, the injection device having an electrical path for each wire of the twisted pair and comprising two coupling devices of N-type and of P-type, respectively, wherein said coupling devices have a first connection pad to a DC power supply line and a second connection pad to a telephone line or coaxial cable adapted to provide a DC voltage and a DC supply current to at least a telecommunication device connected thereto, said coupling devices having an electrical path, defined between said first pad and said second pad, adapted to be crossed by said DC supply current, at least an AC blocking transistor inserted in said electrical path, having a first current terminal functionally coupled to said first pad and a second current terminal functionally coupled to said second pad; a control circuit connected between said second current terminal and a control terminal of said AC blocking transistor, adapted to generate a DC control voltage of the AC blocking transistor to keep it in a linear functioning condition at the edge of a saturation functioning condition when the DC supply current flows through the AC blocking transistor, wherein said control circuit is a low-pass filter adapted to generate said control voltage as a low-pass replica of the voltage on said second current terminal; and wherein said AC blocking transistor is a MOSFET or a BJT, of N-type or of P-type, each inserted in a respective one of said electrical paths. ### Claim 8 (depends on 5) The device for drawing a DC supply current according to claim 5, wherein said telephone line is a twisted pair, the device for drawing the DC supply current having an electrical path for each wire of the twisted pair and comprising two coupling devices of N-type and of P-type, respectively, wherein said coupling devices have a first connection pad to a DC power supply line and a second connection pad to a telephone line or coaxial cable adapted to provide a DC voltage and a DC supply current to at least a telecommunication device connected thereto, said coupling devices having an electrical path, defined between said first pad and said second pad, adapted to be crossed by said DC supply current, at least an AC blocking transistor inserted in said electrical path, having a first current terminal functionally coupled to said first pad and a second current terminal functionally coupled to said second pad; a control circuit connected between said second current terminal and a control terminal of said AC blocking transistor, adapted to generate a DC control voltage of the AC blocking transistor to keep it in a linear functioning condition at the edge of a saturation functioning condition when the DC supply current flows through the AC blocking transistor, wherein said control circuit is a low-pass filter adapted to generate said control voltage as a low-pass replica of the voltage on said second current terminal; and wherein said AC blocking transistor is a MOSFET or a BJT, of N-type or of P-type, each inserted in a respective one of said electrical paths. ### Claim 9 (depends on 4) Telecommunication system adapted to be coupled to a telephone line or a coaxial cable of a building, comprising: a device for injecting a current according to claim 4, installed at a user location and functionally coupled to the telephone line or coaxial cable of the building, configured such to inject a DC supply current through said telephone line or coaxial cable of the building; a device for drawing the DC supply current, wherein said device for drawing a DC supply current from a telephone line, comprises: a transceiver adapted to transmit/receive signals of digital data; an internal powering circuit for drawing said DC supply current, functionally connected to at least an electrical path to be crossed by the DC supply current flowing therethrough and adapted to provide a voltage and a current for powering the de drawing; and a coupling device functionally inserted in said at least one electrical path; wherein said coupling device has a first connection pad to a DC power supply line and a second connection pad to a telephone line or coaxial cable adapted to provide a DC voltage and a DC supply current to at least a telecommunication device connected thereto, said coupling device having an electrical path, defined between said first pad and said second pad, adapted to be crossed by said DC supply current, at least an AC blocking transistor inserted in said electrical path, having a first current terminal functionally coupled to said first pad and a second current terminal functionally coupled to said second pad; a control circuit connected between said second current terminal and a control terminal of said AC blocking transistor, adapted to generate a DC control voltage of the AC blocking transistor to keep it in a linear functioning condition at the edge of a saturation functioning condition when the DC supply current flows through the AC blocking transistor, wherein said control circuit is a low-pass filter adapted to generate said control voltage as a low-pass replica of the voltage on said second current terminal; said device for drawing the DC supply current installed at a location of the building, functionally coupled to the telephone line or coaxial cable of the building such to draw the DC supply current and to transmit/receive data signals through the supply line or coaxial cable of the building towards/from said device for injecting a current. ### Claim 10 (depends on 9) The telecommunication system adapted to be coupled to a telephone line or a coaxial cable of a building according to claim 9, wherein said transceiver is adapted to communications between a xDSL line coupled to said telephone line and a GPON communication; further comprising a phone interface FXO adapted to process POTS signals coming from an interface PSTN, adapted to transcode said POTS signals towards said transceiver. ### Claim 11 (depends on 2) The coupling device according to claim 2, wherein said AC blocking transistor is a MOSFET or a BJT, of N-type or of P-type. ### Claim 12 (depends on 2) A device for injecting a DC supply current in a telephone line, comprising: a transceiver adapted to transmit/receive signals of digital data; a circuit for delivering a supply current (PSE), functionally connected to at least an electrical path, adapted to inject the DC supply current therethrough; a coupling device according to claim 2 functionally inserted in said electrical path. ### Claim 13 (depends on 3) A device for injecting a DC supply current in a telephone line, comprising: a transceiver adapted to transmit/receive signals of digital data; a circuit for delivering a supply current (PSE), functionally connected to at least an electrical path, adapted to inject the DC supply current therethrough; a coupling device according to claim 3 functionally inserted in said electrical path. ### Claim 14 (depends on 13) The device for injecting a DC supply current in a telephone line according to claim 13, further comprising an inductor, inserted in said electrical path, connected between said second current terminal and said second connection pad. ### Claim 15 (depends on 2) A device for drawing a DC supply current from a telephone line, comprising: a transceiver adapted to transmit/receive signals of digital data; an internal powering circuit for drawing said DC supply current functionally connected to at least an electrical path to be crossed by the DC supply current flowing therethrough and adapted to provide a voltage and a current for powering the device for drawing; a coupling device according to claim 2 functionally inserted in said at least one electrical path. ### Claim 16 (depends on 15) The device for drawing a DC supply current according to claim 15, wherein said transceiver is adapted to communications between a xDSL line coupled to said telephone line and a GPON communication; further comprising a phone interface FXO adapted to process POTS signals coming from an interface PSTN, adapted to transcode said POTS signals towards said transceiver. ### Claim 17 (depends on 3) A device for drawing a DC supply current from a telephone line, comprising: a transceiver adapted to transmit/receive signals of digital data; an internal powering circuit for drawing said DC supply current functionally connected to at least an electrical path to be crossed by the DC supply current flowing therethrough and adapted to provide a voltage and a current for powering the device for drawing; a coupling device according to claim 3 functionally inserted in said at least one electrical path. ### Claim 18 (depends on 17) The device for drawing a DC supply current according to claim 17, wherein said transceiver is adapted to communications between a xDSL line coupled to said telephone line and a GPON communication; further comprising a phone interface FXO adapted to process POTS signals coming from an interface PSTN, adapted to transcode said POTS signals towards said transceiver. ### Claim 19 (depends on 8) The device for drawing a DC supply current according to claim 8, wherein said transceiver is adapted to communications between a xDSL line coupled to said telephone line and a GPON communication; further comprising a phone interface FXO adapted to process POTS signals coming from an interface PSTN, adapted to transcode said POTS signals towards said transceiver.