Inline power-based common mode communications in a wired data telecommunications network

An apparatus for communicating a message from a powered device (PD) to power sourcing equipment (PSE) in a wired data telecommunications network, the apparatus comprising:

• means for performing a PD detection and classification to verify that the PD is configured to be supplied with inline power from the PSE;
• means responsive to said means for performing, for establishing an initial inline power relationship between the PD and the PSE so that the PD is receiving an initial minimum level of power from the PSE;
• and
• means for current modulating the inline power at the PD with a predetermined communications protocol to communicate the message from the PD to the PSE;
• wherein means for establishing the initial inline power relationship comprises means for biasing a first pair of conductors with one direct current (DC) voltage level and a second pair of conductors with a second DC voltage level, the difference between the first and second voltage level being a difference voltage, the PD and PSE being powered by the difference voltage, and the difference voltage exceeding 20 Volts,
• wherein the message includes a request for a different minimum level of power from the PSE to the PD,
• and further comprising means responsive to said current modulating for providing the different minimum level of power from the PSE to the PD,
• wherein the first pair of conductors are used for performing at least the function of transmitting data from the PD to the PSE, and the means for current modulating will remain operable to communicate the message from the PD to the PSE even if at least one of the following occurs:
• (a) one conductor of said first pair of conductors is open, and (b) both conductors of said first pair of conductors are shorted together.

A system for communicating a message from a powered device (PD) to power sourcing equipment (PSE) in a wired data telecommunications network, the system comprising:

• circuitry for performing a PD detection and classification to verify that the PD is configured to be supplied with inline power from the PSE;
• circuitry responsive to said circuitry for performing, for establishing an initial inline power relationship between the PD and the PSE so that the PD is receiving an initial minimum level of power from the PSE;
• and
• circuitry for current modulating the inline power at the PD with a predetermined communications protocol to communicate the message from the PD to the PSE;
• wherein circuitry for establishing the initial inline power relationship comprises circuitry for biasing a first pair of conductors with one direct current (DC) voltage level and a second pair of conductors with a second DC voltage level, the difference between the first and second voltage level being a difference voltage, the PD and PSE being powered by the difference voltage, and the difference voltage exceeding 20 Volts,
• wherein the message includes a request for a different minimum level of power from the PSE to the PD,
• and further comprising circuitry responsive to said current modulating for providing the different minimum level of power from the PSE to the PD,
• wherein the first pair of conductors are used for performing at least the function of transmitting data from the PD to the PSE, and the circuitry for current modulating will remain operable to communicate the message from the PD to the PSE even if at least one of the following occurs:
• (a) one conductor of said first pair of conductors is open, and (b) both conductors of said first pair of conductors are shorted together.

A method for communicating a message from power sourcing equipment (PSE) to a powered device (PD) in a wired data telecommunications network, the method comprising:

• performing a PD detection and classification to verify that the PD is configured to be supplied with inline power from the PSE;
• responsive to said performing, establishing an initial inline power relationship between the PD and the PSE so that the PD is receiving an initial minimum level of power from the PSE;
• and
• voltage modulating the inline power at the PSE with a predetermined communications protocol to communicate the message from the PSE to the PD;
• wherein establishing the initial inline power relationship comprises biasing a first pair of conductors with one direct current (DC) voltage level and a second pair of conductors with a second DC voltage level, the difference between the first and second voltage level being a difference voltage, the PD and PSE being powered by the difference voltage, and the difference voltage exceeding 20 Volts,
• wherein the message includes a confirmation of a request for a different minimum level of power from the PSE to the PD,
• and further comprising, responsive to said voltage modulating, providing the different minimum level of power from the PSE to the PD,
• wherein the first pair of conductors are used for performing at least the function of transmitting data from the PD to the PSE, and the voltage modulating will remain operable to communicate the message from the PD to the PSE even if at least one of the following occurs:
• (a) one conductor of said first pair of conductors is open, and (b) both conductors of said first pair of conductors are shorted together.

An apparatus for communicating a message from power sourcing equipment (PSE) to a powered device (PD) in a wired data telecommunications network, the apparatus comprising:

• means for performing a PD detection and classification to verify that the PD is configured to be supplied with inline power from the PSE;
• means responsive to said means for performing, for establishing an initial inline power relationship between the PD and the PSE so that the PD is receiving an initial minimum level of power from the PSE;
• and
• means for voltage modulating the inline power at the PSE with a predetermined communications protocol to communicate the message from the PSE to the PD;
• wherein means for establishing the initial inline power relationship comprises means for biasing a first pair of conductors with one direct current (DC) voltage level and a second pair of conductors with a second DC voltage level, the difference between the first and second voltage level being a difference voltage, the PD and PSE being powered by the difference voltage, and the difference voltage exceeding 20 Volts,
• wherein the message includes a confirmation of a request for a different minimum level of power from the PSE to the PD,
• and further comprising means responsive to said voltage modulating for providing the different minimum level of power from the PSE to the PD,
• wherein the first pair of conductors are used for performing at least the function of transmitting data from the PD to the PSE, and the means for voltage modulating will remain operable to communicate the message from the PD to the PSE even if at least one of the following occurs:
• (a) one conductor of said first pair of conductors is open, and (b) both conductors of said first pair of conductors are shorted together.

A system for communicating a message from power sourcing equipment (PSE) to a powered device (PD) in a wired data telecommunications network, the system comprising:

• circuitry for performing a PD detection and classification to verify that the PD is configured to be supplied with inline power from the PSE;
• circuitry responsive to said circuitry for performing, for establishing an initial inline power relationship between the PD and the PSE so that the PD is receiving an initial minimum level of power from the PSE;
• and
• circuitry for voltage modulating the inline power at the PSE with a predetermined communications protocol to communicate the message from the PSE to the PD;
• wherein circuitry for establishing the initial inline power relationship comprises circuitry for biasing a first pair of conductors with one direct current (DC) voltage level and a second pair of conductors with a second DC voltage level, the difference between the first and second voltage level being a difference voltage, the PD and PSE being powered by the difference voltage, and the difference voltage exceeding 20 Volts,
• wherein the message includes a confirmation of a request for a different minimum level of power from the PSE to the PD,
• and further comprising circuitry responsive to said voltage modulating for providing the different minimum level of power from the PSE to the PD,
• wherein the first pair of conductors are used for performing at least the function of transmitting data from the PD to the PSE, and the circuitry for voltage modulating will remain operable to communicate the message from the PD to the PSE even if at least one of the following occurs:
• (a) one conductor of said first pair of conductors is open, and (b) both conductors of said first pair of conductors are shorted together.

A powered device (PD) having a requirement for a minimum level of inline power supplied over a wired data telecommunications network from power sourcing equipment (PSE) to which the PD is coupled, the minimum level of inline power requirement subject to change from time to time, the PD comprising:

• circuitry for determining a minimum level of inline power required by the PD;
• circuitry for current modulating the inline power supplied over the wired data telecommunications network;
• and
• an encoder for encoding a message from the PD to the PSE on the current modulating circuitry communicating a present need for a changed minimum level of inline power,
• wherein the wired data telecommunications network includes a first pair of conductors used for performing at least the functions of supplying inline power to the PD from the PSE, encoding the message on the current modulating circuitry, and transmitting data from the PD to the PSE, and the current modulating circuitry will remain operable to communicate the message from the PD to the PSE even if at least one of the following occurs:
• (a) one conductor of said first pair of conductors is open, and (b) both conductors of said first pair of conductors are shorted together.

A powered device (PD) having a requirement for a minimum level of inline power supplied over a wired data telecommunications network from power sourcing equipment (PSE) to which the PD is coupled, the minimum level of inline power requirement subject to change from time to time, the PD comprising:

• means for determining a minimum level of inline power required by the PD;
• means for current modulating the inline power supplied over the wired data telecommunications network;
• and
• means for encoding a message from the PD to the PSE on the current modulating means communicating a present need for a changed minimum level of inline power,
• wherein the wired data telecommunications network includes a first pair of conductors used for performing at least the functions of supplying inline power to the PD from the PSE, encoding the message on the current modulating means, and transmitting data from the PD to the PSE, and the current modulating means will remain operable to communicate the message from the PD to the PSE even if at least one of the following occurs:
• (a) one conductor of said first pair of conductors is open, and (b) both conductors of said first pair of conductors are shorted together.

A method for operating a powered device (PD) having a requirement for a minimum level of inline power supplied over a wired data telecommunications network from power sourcing equipment (PSE) to which the PD is coupled, the minimum level of inline power requirement subject to change from time to time, the method comprising:

• determining a minimum level of inline power required by the PD;
• and
• encoding a message from the PD to the PSE by current modulating the inline power supplied over the wired data telecommunications network to the PD to communicate a need for a changed minimum level of inline power,
• wherein the wired data telecommunications network includes a first pair of conductors used for performing at least the functions of supplying inline power to the PD from the PSE, encoding the message by current modulating the inline power, and transmitting data from the PD to the PSE, and the current modulating will remain operable to communicate the message from the PD to the PSE even if at least one of the following occurs:
• (a) one conductor of said first pair of conductors is open, and (b) both conductors of said first pair of conductors are shorted together.

A power sourcing equipment (PSE) device having a capacity to provide up to a first quantity of inline power over a wired data telecommunications network to a powered device (PD) to which the PSE is coupled, the PSE comprising:

• circuitry for receiving a request from the PD for a changed minimum level of inline power required by the PD;
• circuitry for voltage modulating the inline power supplied over the wired data telecommunications network from the PSE to the PD;
• and
• an encoder for encoding a message from the PSE to the PD on the voltage modulating circuitry communicating a present changed minimum level of inline power to be supplied from the PSE to the PD,
• wherein the wired data telecommunications network includes a first pair of conductors used for performing at least the functions of supplying inline power to the PD from the PSE, encoding the message on the voltage modulating circuitry, and transmitting data from the PD to the PSE, and the voltage modulating circuitry will remain operable to communicate the message from the PD to the PSE even if at least one of the following occurs:
• (a) one conductor of said first pair of conductors is open, and (b) both conductors of said first pair of conductors are shorted together.

A power sourcing equipment (PSE) device having a capacity to provide up to a first quantity of inline power over a wired data telecommunications network to a powered device (PD) to which the PSE is coupled, the PSE comprising:

• means for receiving a request from the PD for a changed minimum level of inline power required by the PD;
• means for voltage modulating the inline power supplied over the wired data telecommunications network from the PSE to the PD;
• and
• means for encoding a message from the PSE to the PD on the voltage modulating means communicating a present changed minimum level of inline power to be supplied from the PSE to the PD,
• wherein the wired data telecommunications network includes a first pair of conductors used for performing at least the functions of supplying inline power to the PD from the PSE, encoding the message on the voltage modulating means, and transmitting data from the PD to the PSE, and the voltage modulating means will remain operable to communicate the message from the PD to the PSE even if at least one of the following occurs:
• (a) one conductor of said first pair of conductors is open, and (b) both conductors of said first pair of conductors are shorted together.

A method for operating a power sourcing equipment (PSE) device having a capacity to provide up to a first quantity of inline power over a wired data telecommunications network to a powered device (PD) to which the PSE is coupled, the method comprising:

• receiving a request from the PD for a changed minimum level of inline power required by the PD;
• voltage modulating the inline power supplied over the wired data telecommunications network from the PSE to the PD;
• and
• encoding a message from the PSE to the PD with said voltage modulating communicating a present changed minimum level of inline power to be supplied from the PSE to the PD,
• wherein the wired data telecommunications network includes a first pair of conductors used for performing at least the functions of supplying inline power to the PD from the PSE, encoding the message with the voltage modulating, and transmitting data from the PD to the PSE, and the voltage modulating will remain operable to communicate the message from the PD to the PSE even if at least one of the following occurs:
• (a) one conductor of said first pair of conductors is open, and (b) both conductors of said first pair of conductors are shorted together.

A powered device (PD) for communicating a message to power sourcing equipment (PSE) in a wired data telecommunications network, the PD comprising:

• a first circuit for participating in a PD detection and classification process to verify that the PD is configured to be supplied with inline power from the PSE;
• a second circuit responsive to said first circuit, for establishing an initial inline power relationship between the PD and the PSE so that the PD is receiving an initial minimum level of power from the PSE;
• and
• a third circuit for current modulating the power at the PD with a predetermined communications protocol to communicate the message from the PD to the PSE;
• wherein the second circuit for establishing the initial inline power relationship is configured to bias a first pair of conductors with one direct current (DC) voltage level and a second pair of conductors with a second DC voltage level, the difference between the first and second voltage level being a difference voltage, the PD and PSE being powered by the difference voltage, and the difference voltage exceeding 20 Volts,
• wherein the message includes a request for a different minimum level of power from the PSE to the PD,
• and wherein the second circuit is further configured, responsive to said current modulating, to provide the different minimum level of power from the PSE to the PD,
• and wherein the first pair of conductors are used for performing at least the function of transmitting data from the PD to the PSE, and the third circuit will remain operable to communicate the message from the PD to the PSE even if at least one of the following occurs:
• (a) one conductor of said first pair of conductors is open, and (b) both conductors of said first pair of conductors are shorted together.

A power sourcing equipment (PSE) device for receiving a message from a powered device (PD) in a wired data telecommunications network, the PSE comprising:

• a first circuit for participating in a detection and classification process to verify that the PD is configured to be supplied with inline power from the PSE;
• a second circuit responsive to said first circuit, for establishing an initial inline power relationship between the PD and the PSE so that the PD is receiving an initial minimum level of power from the PSE;
• and
• a third circuit for demodulating a modulated current signal at the PSE received from the PD to receive the message from the PD at the PSE;
• wherein the second circuit for establishing the initial inline power relationship is configured to bias a first pair of conductors with one direct current (DC) voltage level and a second pair of conductors with a second DC voltage level, the difference between the first and second voltage level being a difference voltage, the PD and PSE being powered by the difference voltage, and the difference voltage exceeding 20 Volts,
• wherein the message includes a request for a different minimum level of power from the PSE to the PD,
• and wherein the second circuit is further configured, responsive to said modulated current signal, to provide the different minimum level of power from the PSE to the PD,
• wherein the first pair of conductors are used for performing at least the function of transmitting data from the PD to the PSE, and the third circuit for current demodulating will remain operable to receive the message from the PD to the PSE even if at least one of the following occurs:
• (a) one conductor of said first pair of conductors is open, and (b) both conductors of said first pair of conductors are shorted together.

A method for communicating a message from a first station via a second station to a third station in a wired data telecommunications network, the first station comprising a powered device (PD), the second station comprising power sourcing equipment (PSE), and the third station comprising a PD, and the wired data telecommunications network having at least a first pair of conductors and a second pair of conductors for coupling the first station to the second station and at least a third pair of conductors and a fourth pair of conductors for coupling the second station to the third station, the method comprising:

• biasing the first pair of conductors with one direct current (DC) voltage level and the second pair of conductors with a second DC voltage level, the difference between the first and second voltage levels being a first difference voltage;
• and
• voltage modulating the difference voltage with a predetermined communications protocol to communicate the message from the first station to the second station;
• transmitting the message from the first station to the second station;
• wherein during said biasing the difference voltage exceeds 20 Volts, wherein the message includes a request for a different minimum level of power from the PSE to the PD,
• and further comprising, responsive to said voltage modulating, providing the different minimum level of power from the PSE to the PD,
• and further comprising:
• biasing the third pair of conductors with the one DC voltage level and the fourth pair of conductors with the second DC voltage level, the difference between the third and fourth voltage levels being a second difference voltage;
• modulating the second difference voltage with a predetermined communications protocol to communicate the message from the second station to the third station, the modulating including at least one of current modulating and voltage modulating;
• and
• transmitting the message from the second station to the third station.

A method for communicating a message from a first station via a second station to a third station in a wired data telecommunications network, the first station comprising a powered device (PD), the second station comprising power sourcing equipment (PSE), and the third station comprising a PD, and the wired data telecommunications network having at least a first pair of conductors and a second pair of conductors for coupling the first station to the second station and at least a third pair of conductors and a fourth pair of conductors for coupling the second station to the third station, the method comprising:

• biasing the first pair of conductors with one direct current (DC) voltage level and the second pair of conductors with a second DC voltage level, the difference between the first and second voltage levels being a first difference voltage;
• and
• current modulating the difference voltage with a predetermined communications protocol to communicate the message from the first station to the second station;
• transmitting the message from the first station to the second station;
• wherein said modulating takes place while at least one of the first station and the second station is powered by the difference voltage;
• wherein during said biasing the difference voltage exceeds 20 Volts,
• wherein the message includes a request for a different minimum level of power from the PSE to the PD,
• and further comprising, responsive to said current modulating, providing the different minimum level of power from the PSE to the PD,
• and further comprising:
• biasing the third pair of conductors with the one DC voltage level and the fourth pair of conductors with the second DC voltage level, the difference between the third and fourth voltage levels being a second difference voltage;
• modulating the second difference voltage with a predetermined communications protocol to communicate the message from the second station to the third station, the modulating including at least one of current modulating and voltage modulating;
• and
• transmitting the message from the second station to the third station.

A method for communicating a message from a first station via a second station to a third station in a wired data telecommunications network, the first station comprising a powered device (PD), the second station comprising power sourcing equipment (PSE), and the third station comprising a PD, and the wired data telecommunications network having at least a first pair of conductors and a second pair of conductors for coupling the first station, the second station and the third station, the method comprising:

• biasing the first pair of conductors with one direct current (DC) voltage level and the second pair of conductors with a second DC voltage level, the difference between the first and second voltage levels being a difference voltage;
• and
• voltage modulating the difference voltage with a predetermined communications protocol to communicate the message from the first station to the second station;
• transmitting the message from the first station to the second station;
• wherein said modulating takes place while at least one of the first station and the second station is powered by the difference voltage;
• wherein during said biasing the difference voltage exceeds 20 Volts,
• wherein the message includes a request for a different minimum level of power from the PSE to the PD,
• and further comprising, responsive to said voltage modulating, providing the different minimum level of power from the PSE to the PD, and further comprising:
• current modulating the difference voltage with a predetermined communications protocol to communicate the message from the second station to the third station;
• transmitting the message from the second station to the third station.

A method for communicating a first message from a first station to a third station and a second message from the second station to the first station in a wired data telecommunications network, a second station providing inline power to the first station and the second station, the first station comprising a powered device (PD), the second station comprising power sourcing equipment (PSE), and the third station comprising a PD, and the wired data telecommunications network having at least a first pair of conductors and a second pair of conductors for coupling the first station, the second station and the third station, the method comprising:

• biasing the first pair of conductors with one direct current (DC) voltage level and the second pair of conductors with a second DC voltage level, the difference between the first and second voltage levels being a difference voltage;
• and
• voltage modulating the difference voltage with a predetermined communications protocol to communicate the first message from the first station to the second station;
• transmitting the first message from the first station to the second station;
• wherein said modulating takes place while at least one of the first station and the second station is powered by the difference voltage;
• wherein during said biasing the difference voltage exceeds 20 Volts,
• wherein the first message includes a request for a different minimum level of power from the PSE to the PD of the first station,
• and further comprising, responsive to said voltage modulating, providing the different minimum level of power from the PSE to the PD of the first station, and further comprising:
• current modulating the difference voltage with a predetermined communications protocol to communicate the second message from the second station to the first station;
• transmitting the second message from the second station to the first station.

A method for communicating a message from a first station to at least one second station in a wired data telecommunications network, the first station and the second station comprising power sourcing equipment (PSE), and the wired data telecommunications network having at least a first pair of conductors and a second pair of conductors for coupling the first station to the at least one second station, the method comprising:

• periodically conducting at the first station a first discovery process to determine if a powered device (PD) is present on the wired data telecommunications network, followed by a back off period;
• listening during the back off period for a special signature indicating the presence of a PSE at the second station;
• detecting the presence of a PSE at the second station;
• and
• communicating, responsive to said detecting, with the PSE at the second station.

An apparatus for communicating a message from a first station to at least one second station in a wired data telecommunications network, the first station and the second station comprising power sourcing equipment (PSE), and the wired data telecommunications network having at least a first pair of conductors and a second pair of conductors for coupling the first station to the at least one second station, the apparatus comprising:

• means for periodically conducting at the first station a first discovery process to determine if a powered device (PD) is present on the wired data telecommunications network, followed by a back off period;
• means for listening during the back off period for a special signature indicating the presence of a PSE at the second station;
• means for detecting the presence of a PSE at the second station;
• and
• means for communicating, responsive to said detecting, with the PSE at the second station.

A system for communicating a message from a first station to at least one second station in a wired data telecommunications network, the first station and the second station comprising power sourcing equipment (PSE), and the wired data telecommunications network having at least a first pair of conductors and a second pair of conductors for coupling the first station to the at least one second station, the system comprising:

• circuitry for periodically conducting at the first station a first discovery process to determine if a powered device (PD) is present on the wired data telecommunications network, followed by a back off period;
• circuitry for listening during the back off period for a special signature indicating the presence of a PSE at the second station;
• circuitry for detecting the presence of a PSE at the second station;
• and
• circuitry for communicating, responsive to said detecting, with the PSE at the second station.

An apparatus for communicating a message from a first station to at least one second station in a wired data telecommunications network, the first station and the second station comprising power sourcing equipment (PSE), and the wired data telecommunications network having at least a first pair of conductors and a second pair of conductors for coupling the first station to the at least one second station, the apparatus comprising:

• a discoverer for periodically conducting at the first station a first discovery process to determine if a powered device (PD) is present on the wired data telecommunications network, followed by a back off period;
• a receiver for listening during the back off period for a special signature indicating the presence of a PSE at the second station;
• a detector for detecting the presence of a PSE at the second station;
• and
• a communicator for communicating, responsive to said detecting, with the PSE at the second station.