Enabling cisco legacy power to support IEEE 802.3 AF standard power

• US 20040156496A1
• Filed: 02/06/2003
• Published: 08/12/2004
• Est. Priority Date: 02/06/2003
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Karam, Roger A.
• Granted Patent: US 6,912,282 B2
• Time in Patent Office: Days
• US Class Current: 379/413
• CPC Class Codes: H04L 12/10 Current supply arrangements

Abstract

An apparatus and method for enabling Cisco legacy power to support IEEE 802.3 AF standard power. A network power system capable of delivering data terminal equipment power via a media dependent interface includes power source equipment according to Cisco legacy power and at least one powered device according to IEEE standard power. A power compatibility module is inserted between the power source equipment and the powered device to enable the power source equipment to appear according to IEEE standard power and the powered device to appear according to Cisco legacy power. The module includes switches, a DC/DC converter, an IEEE power source equipment circuit, and an isolator. The module optionally includes a user signaling device for communicating operating conditions of the module to a user. The module may be connected to two ports of the power source equipment to supply adequate power levels to the powered device.

Claims

1. A power compatibility module for data terminal equipment power via a media dependent interface, the module comprising:

a first data and power signal path for signals traveling in a first direction;

a second data and power signal path for signals traveling in a second direction different from the first direction;

at least two switches each having a first contact and a second contact, wherein each of the first contacts is coupled to the first signal path and each of the second contacts is coupled to the second signal path;

a DC/DC converter having an input coupled across the first and second signal paths;

an IEEE power source equipment circuit having an input coupled to the output of the DC/DC converter; and

an isolator having an input coupled to an output of the IEEE circuit and an output coupled to the second signal path.

2. The module as defined in claim 1, further comprising at least two filters wherein one of each filters is connected in series with one of each of the at least two switches.

3. The module as defined in claim 1, further comprising a user signaling device coupled to the IEEE circuit for communicating operating conditions of the module to a user.

4. The module as defined in claim 1, further comprising:

a third data and power signal path for signals traveling in the first direction; and

a fourth data and power signal path for signals traveling in the second direction,

wherein the DC/DC converter is also coupled across the third and fourth signal paths.

5. A data terminal equipment capable of receiving power via a media dependent interface, the data terminal equipment comprising:

a power compatibility module comprising;

a first data and power signal path for signals traveling in a first direction;

a second data and power signal path for signals traveling in a second direction different from the first direction;

at least two switches each having a first contact and a second contact, wherein each of the first contacts is coupled to the first signal path and each of the second contacts is coupled to the second signal path;

a DC/DC converter having an input coupled across the first and second signal paths;

an IEEE power source equipment circuit having an input coupled to the output of the DC/DC converter and an output coupled to each of the control contacts of the at least two switches; and

an isolator having an input coupled to an output of the IEEE circuit and an output coupled to the second signal path.

6. The data terminal equipment as defined in claim 5, wherein the module further comprises at least two filters wherein one of each filters is connected in series with one of each of the at least two switches.

7. The data terminal equipment as defined in claim 5, wherein the module further comprises a user signaling device coupled to the IEEE circuit for communicating operating conditions of the module to a user.

8. The data terminal equipment as defined in claim 5, wherein the module further comprises:

a third data and power signal path for signals traveling in the first direction; and

a fourth data and power signal path for signals traveling in the second direction,

wherein the DC/DC converter is also coupled across the third and fourth signal paths.

9. A method of providing compatibility to a network power system having equipment capable of two power schemes to deliver data terminal equipment power via a media dependent interface, the network power system including power source equipment capable of one power scheme and a powered device capable of a second power scheme different from the first power scheme, the method comprising:

enabling the power source equipment to operate according to the first power scheme while appearing to the powered device to be operating according to the second power scheme; and

enabling the powered device to operate according to the second power scheme while appearing to the power source equipment to be operating according to the first power scheme.

10. An apparatus for providing compatibility to a network power system having equipment capable of two power schemes to deliver data terminal equipment power via a media dependent interface, the network power system including power source equipment capable of one power scheme and a powered device capable of a second power scheme different from the first power scheme, the apparatus comprising:

means for enabling the power source equipment to operate according to the first power scheme while appearing to the powered device to be operating according to the second power scheme; and

means for enabling the powered device to operate according to the second power scheme while appearing to the power source equipment to be operating according to the first power scheme.

11. A network power system for delivering data terminal equipment (DTE) power via a media dependent interface, the network power system having a first data and power signal path for signals traveling in a first direction and a second data and power signal path for signals traveling in a second direction different from the first direction, the system comprising:

a power compatibility module capable of a first power scheme, the module comprising;

at least two switches each having a first contact and a second contact, wherein each of the first contacts is coupled to the first signal path and each of the second contacts is coupled to the second signal path;

an IEEE power source equipment circuit having an input coupled across the first and second signal paths;

an isolator having an input coupled to an output of the IEEE circuit and an output coupled to the second signal path; and

a DTE capable of a second power scheme, the DTE comprising;

a DC/DC converter having an input coupled across the first and second signal paths.

12. The system as defined in claim 11, wherein the module further comprises at least two filters wherein one of each filters is connected in series with one of each of the at least two switches.

13. The system as defined in claim 11, wherein the module further comprises a user signaling device coupled to the IEEE circuit for communicating operating conditions of the module to a user.

14. The system as defined in claim 11, further comprising:

a third data and power signal path for signals traveling in the first direction; and

a fourth data and power signal path for signals traveling in the second direction,

wherein the DC/DC converter of the DTE is also coupled across the third and fourth signal paths.