Power over ethernet management devices and connection between ethernet devices
In one embodiment, a connection is maintained between a pair of ethernet ports that have circuitry connected in series with the ports and receiving power-over-ethernet (PoE) from one of the ports, by providing a controllable bypass circuit coupled to the pair of ethernet ports in parallel with the circuitry receiving power-over-ethernet, sensing a preselected condition, and opening and closing the bypass circuit in response to the presence or absence of the preselected condition. Power sourcing equipment (PSE) may supply the one of the ports with power over ethernet, and the circuitry may transports data between the pair of ethernet ports. The circuitry may also supply the switch with a control signal in response to the detection of the preselected condition.
1. A network device having a pair of ethernet ports and comprising
a powered device containing circuitry connected in series with said ethernet ports and receiving power-over-ethernet (PoE) from one of said ports,
a bypass circuit coupled to said pair of ethernet ports in parallel with said circuitry in said powered device receiving the power-over-ethernet for coupling said ports,
a pair of double-throw, double-pole relay coils energized by power over ethernet, and two pairs of contacts for (a) opening said bypass circuit to couple said pair of ethernet ports via said circuitry in said powered device and (b) connecting said ethernet ports to said circuitry in said powered device, in response to energization of said relay coils, and for (a) closing said bypass circuit to couple said pair of ethernet ports directly and (b) disconnecting said circuitry in said powered device from said ethernet ports, in response to de-energization of said relay coils.
2. The network device of claim 1 wherein said circuitry in said powered device transports data between said pair of ethernet ports.
3. The network device of claim 1 wherein said circuitry in said powered device is coupled to said switch and supplies said switch with a control signal in response to detection of said preselected condition.
4. The network device of claim 3 wherein said circuitry in said powered device includes a CPU that detects said preselected condition and produces said control signal.
5. The network device of claim 1 wherein said preselected condition is a power failure.
6. The network device of claim 1 wherein said sensing element is an ethernet transformer, and said switch is a pair of relays receiving power from at least one of said ethernet ports.
7. The network device of claim 6 wherein said relays open said bypass circuit and connect said ethernet ports to said circuitry in said powered device in the presence of power, and close said bypass circuit and disconnect said circuitry in said powered device from said ethernet ports in response to a power failure.
8. A method of maintaining a connection between a pair of ethernet ports in a powered device that contains circuitry connected in series with said ports and receiving power-over-ethernet (PoE) and data from one of said ports, said method comprising
providing a controllable bypass circuit coupled to said pair of ethernet ports in parallel with said circuitry in said powered device receiving power-over-ethernet, said controllable bypass circuit receiving only data from said one of said ports,
in response to energization by power over Ethernet of a pair of double-throw, double-pole relay coils having two pairs of contacts, (a) opening said bypass circuit to couple said pair of ethernet ports via said circuitry in said powered device and (b) connecting said ethernet ports to said circuitry in said powered device, and
in response to de-energization of said relay coils, (a) closing said bypass circuit to couple said pair of ethernet ports directly and (b) disconnecting said circuitry in said powered device from said ethernet ports.
9. A network device having a pair of ethernet ports and comprising
a powered device containing circuitry connected in series with said ethernet ports for handling ethernet traffic and for detecting incompatibility of ethernet devices coupled to said ethernet ports in normal operation, and correcting any detected incompatibility,
a bypass circuit coupled to said pair of ethernet ports in parallel with said circuitry in said powered device for coupling said ports, and,
a pair of double-throw, double-pole relay coils energized by power over ethernet, and two pairs of contacts for (a) opening said bypass circuit to couple said pair of ethernet ports via said circuitry in said powered device and (b) connecting said ethernet ports to said circuitry in said powered device, in response to energization of said relay coils, and for (a) closing said bypass circuit to couple said pair of ethernet ports directly and (b) disconnecting said circuitry in said powered device from said ethernet ports, in response to de-energization of said relay coils.
10. The network device of claim 9 wherein said incompatibility is detected by determining the link partner capability of the link partner at each of said ports, and then comparing said capabilities to detect any incompatibility.
11. The network device of claim 9 wherein detected incompatibility is corrected by implementing a selectable crossover function when in bypass mode.