Patent Publication Number: US-7221261-B1

Title: System and method for indicating a configuration of power provided over an ethernet port

Description:
RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional application Ser. No. 60/508,724 entitled “Method and Apparatus for Power Over Ethernet” filed on Oct. 2, 2003 by Brent Dimick, Bruce Klingensmith, and Elton Armstrong, having the same assignee as the present application; and is related to U.S. patent application Ser. No. 10/953,431, entitled, “SYSTEM AND METHOD FOR PROVIDING DIFFERENT POLARITIES OF POWER SUPPLIED OVER ETHERNET CABLES”, and U.S. patent application Ser. No. 10/953,408, entitled, “SYSTEM AND METHOD FOR SAFELY CONTROLLING, AND RECEIVING STATUS OF, POWER OVER ETHERNET” now U.S. Pat. 7,187,268 each filed concurrently herewith by the same inventors and having the same assignee as the present application, and all of the above-referenced applications are incorporated by reference in their entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention is related to power control systems and more specifically to power control systems for power over Ethernet cables. 
     BACKGROUND OF THE INVENTION 
     Conventional Ethernet cables employ eight wires, only four of which are used to carry communication signals. The other wires are available for other uses. One such use is to carry power from one Ethernet-connected device to another such device. This allows the device receiving the power to avoid the need to obtain power from a separate source. 
     Several standards have been developed for supplying power over Ethernet cables. One standard is the conventional 802.3af proposed by the IEEE, which supplies 48 volt power over at least two of the wires, using either of the two polarities, such as +48 volts or −48 volts. The IEEE is an organization composed of multiple member organizations that develop standards, among other things. Another standard for supplying power over Ethernet cables has been promulgated by Cisco Systems, Inc., and supplies −48 volt power. Cisco Systems, Inc., is a corporation that supplies communications equipment, including Ethernet processing equipment. The systems drawing such power are typically compatible with only one such power polarity. 
     As described herein, power having either type of polarity may be supplied via Ethernet ports by configuring the port. Once configured, however, the port will be incompatible with systems drawing power having the other type of polarity. If the port is provided in a location inaccessible to, or merely different from, the location at which configuration information is entered, it may be impossible or inconvenient to determine the polarity of the supplied power for which the port has been configured when the user is near the port. What is needed is a system and method that can indicate near an Ethernet port the polarity of supplied power for which the Ethernet port has been configured. 
     SUMMARY OF INVENTION 
     A system and method receives configuration information about power to be provided over a communication network connector containing communication leads and power leads and provides status information about the configuration at least near the communication network connector. The communication network connector may be a conventional RJ-45 connector or another conventional connector. The communication leads may communicate conventional Ethernet signals or other conventional communication network signals. The status information may be provided using a lamp, such as one or more conventional LEDs, and may be provided by flashing at least one of the one or more LEDs, changing the color of one or more LEDs or signaling via one or more solid color LEDs, or may be provided using other methods such as via tones from a speaker. The configuration information distinguishes between a power configuration specified by an industry standards organization and a power configuration specified by a corporation. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block schematic diagram of a conventional computer system. 
         FIG. 2  is a block schematic diagram of a system for configuring and providing power to a cable used for an Ethernet connection and for providing information about such configuration according to one embodiment of the present invention. 
         FIG. 3 , consisting of  FIGS. 3A and 3B , is a flowchart illustrating a method of configuring and providing power to a cable used for an Ethernet connection and for providing information about such configuration according to one embodiment of the present invention. 
         FIG. 4  is a flowchart illustrating a method of providing status information about power provided via the same port as that used for an Ethernet connection according to one embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
     The present invention may be implemented as computer software on a conventional computer system. Referring now to  FIG. 1 , a conventional computer system  150  for practicing the present invention is shown. Processor  160  retrieves and executes software instructions stored in storage  162  such as memory, which may be Random Access Memory (RAM) and may control other components to perform the present invention. Storage  162  may be used to store program instructions or data or both. Storage  164 , such as a computer disk drive or other nonvolatile storage, may provide storage of data or program instructions. In one embodiment, storage  164  provides longer term storage of instructions and data, with storage  162  providing storage for data or instructions that may only be required for a shorter time than that of storage  164 . Input device  166  such as a computer keyboard or mouse or both allows user input to the system  150 . Output  168 , such as a display or printer, allows the system to provide information such as instructions, data or other information to the user of the system  150 . Storage input device  170  such as a conventional floppy disk drive or CD-ROM drive accepts via input  172  computer program products  174  such as a conventional floppy disk or CD-ROM or other nonvolatile storage media that may be used to transport computer instructions or data to the system  150 . Computer program product  174  has encoded thereon computer readable program code devices  176 , such as magnetic charges in the case of a floppy disk or optical encodings in the case of a CD-ROM which are encoded as program instructions, data or both to configure the computer system  150  to operate as described below. 
     In one embodiment, each computer system  150  is a conventional SUN MICROSYSTEMS ULTRA 10 workstation running the SOLARIS operating system commercially available from SUN MICROSYSTEMS, Inc. of Mountain View, Calif.; a PENTIUM-compatible personal computer system such as are available from DELL COMPUTER CORPORATION of Round Rock, Tex. running a version of the WINDOWS operating system (such as 95, 98, Me, XP, NT or 2000) commercially available from MICROSOFT Corporation of Redmond Wash. or the FreeBSD operating system commercially available from the website of FreeBSD.org; or a Macintosh computer system running the MACOS or OPENSTEP operating system commercially available from APPLE COMPUTER CORPORATION of Cupertino, Calif. and the NETSCAPE browser commercially available from NETSCAPE COMMUNICATIONS CORPORATION of Mountain View, Calif. or INTERNET EXPLORER browser commercially available from MICROSOFT above, although other systems may be used. 
     Referring now to  FIG. 2 , a system for configuring and providing power to a cable used for an Ethernet connection and for providing information about such configuration is shown according to one embodiment of the present invention. 
     Power Conversion 
     Power is received from a conventional power supply, such as a 12 volt power supply, at input  242  to fuse/filter  240 , which optionally filters the power via conventional capacitors and passes the power through fused links to voltage converter  250 . 
     Voltage converter  250  isolates the power and converts it to any various voltages that may be required by components of system  200  and other devices to which system  200  will supply power. In one embodiment, voltage converter  250  contains 12 volt to −48 volt isolated inverter  252 , −48 volt to 12 volt inverter  256  and 12 volt to 3.3 volt and −5 volt switcher  258 . 
     12 volt to −48 volt isolated inverter  252  receives the power from fuse/filter  240 , isolates it and converts it to −48 volts DC, and supplies the isolated −48 volt DC power to power harness  254 , power polarity switcher  226  and to −48 volt to 12 volt inverter  256 . 
     −48 volt to 12 volt inverter  256  receives the −48 volt isolated power and converts it to 12 volt power, and provides the 12 volt power to power harness  254  and to 12 volt to 3.3 volt and −5 volt switcher  258 . 12 volt to 3.3 volt and −5 volt switcher  258  receives the 12 volt power and converts it to 3.3 volts, which it supplies to harness  254 , and −5 volts, which it also supplies to harness  254 . 
     In one embodiment, the outputs of 12 volt to −48 volt isolated inverter  252 , −48 volt to 12 volt inverter  256  and 12 volt to 3.3 volt and −5 volt switcher  258  are coupled to components of system  200  that draw power, via power harness  254  shown in the figure as a single cable to avoid cluttering the Figure. Power manager  202 , user interface manager  210  and wireless access manager  204  may receive power from power harness  254  or they may draw power from the same source as supplies power to power input  242  or from a different source. 
     As used herein, the term “power” includes power such as would be supplied from a conventional power supply and that is used to operate a system, such as by connecting one lead to ground and another lead to the Vcc input of a conventional integrated circuit, and excludes communication or other signals that only communicate information. 
     Configuration of Polarity 
     A user may configure the system  200  to provide power over Ethernet using one of two polarities: one polarity provides direct current at −48V and the other polarity provides direct current at +48V. To configure the system, the user communicates with user interface manager  210  via input/output  208 , which may be coupled to a conventional keyboard/monitor/mouse or other set of input and/or output devices, such as a personal computer system, none of which are shown. User interface manager  210  may have suitable interfaces for communication with such input and/or output devices, and/or may include or be coupled to a conventional Ethernet interface running conventional protocols such as TCP/IP to allow the user to communicate with user interface manager  210  via a network-coupled personal computer running a browser. In this case, user interface manager  210  provides the user interface via one or more web pages. 
     User interface manager  210  prompts the user for the power configuration to be used to supply power and receives the requested indication of the power configuration, all via input/output  208  as described above. In one embodiment, there may be multiple Ethernet ports through which power can be provided, and if each port may supply power using a different configuration, the indication also indicates an identifier of the port for which the configuration corresponds. User interface manager  210  internally stores the indication of the power configuration (and, optionally, the port identifier), and provides the indication (and optionally the port identifier) to isolator  212 . 
     Isolator  212  contains one or more conventional isolators such as a one or more opto-isolators (e.g. Model HCPL-063N receiving signals from port  211  and HCPL-063L providing signals to port  211 , both available from Agilent Technologies of Palo Alto, Calif.), and serves to electrically isolate user interface manager  210 , power manager  202 , wireless access manager  204  and other equipment that is connected to system  200  via port  211  to ensure that power disruptions in system  200  are not transmitted to devices  210 ,  204 ,  202  or other devices that may be coupled to system  200  via port  211 . Isolator  212  provides to power sense controller  214  the indication of the power configuration (and the optional port identifier) it receives from user interface manager  210 . 
     In one embodiment, power sense controller  214  receives the indication of the power configuration and provides a visual display of the power configuration using display indicators  216 . Display indicators  216  may include conventional display indicators such as one or more light emitting diodes (LEDs) or other similar status indicators. In one embodiment, status of the power configuration may be provided by illuminating the display indicator for the corresponding port in a different color to indicate the polarity of that port, such as yellow for Cisco or IEEE-compatible −48 volt power and green for IEEE-compatible +48 volt power, although other methods of indicating the polarity may be used. In one embodiment, until the power conditions have been detected for a port as described below, power sense controller  214  flashes the display indicator for that port. 
     In one embodiment, display indicators  216  include one or more conventional LEDs or other indicators that are physically near (e.g. within 2 inches) the opening of power output/network connector  232 . In one embodiment, display indicators are also used to display the status of the network connection occurring through the Ethernet leads  234  of power output/network connector  232  that is described in more detail below, and in another embodiment, they are provided in addition to those used for status. In such other embodiment, display indicators used for network status are provided adjacent to the network connector  232  and those used to display power configuration are provided further away from the network connector  232  for which status is being displayed, but still within a few inches of the network connector  232 . Such network status may be provided to display indicators  216  by wireless access manager  204 , described in more detail below. 
     Power sense controller  214  uses the indication of the power configuration it receives from isolator  212  to determine in which position the power polarity switcher  226  should be held. Power sense controller  214  determines that power polarity switcher  226 , described in more detail below, should be in one position if an indication of one type of power configuration is received, and determines that power polarity switcher  226  should be in another position if the other type of power configuration is received. Power sense controller  214  then provides to power polarity controller  222  a polarity signal (indicating either positive or negative polarity) corresponding to the determination it makes as described above. In the event that ports may be individually configured, power sense controller  214  provides the polarity signal to cause power that can be applied to each port to match the configuration indicated for that port. 
     In one embodiment, power sense controller  214  is a conventional microcontroller, such as the model PIC 16F872 commercially available from Microchip, Inc. of Chandler, AZ, and power polarity controller  222 , described in more detail below, is a conventional quad network power controller, such as the model LTC 4255 commercially available from Linear Technology of Milpitas, CA. In such embodiment, the voltages of each of these devices is incompatible, and so voltage level translator  220  performs the voltage translation between such devices. 
     Voltage level translator  220  performs translation of signals from power sense controller  214  to and from power polarity controller  222 . To translate from power sense controller  214  to power polarity controller  222 , voltage level translator  220  connects signals from the power sense controller  214  to the gate of a conventional n-FET, and connects −5.0 volts to the source of the n-FET. The drain is coupled to the input of power polarity controller  222  via a 1K-Ohm resistor. A 665 Ohm resistor is also coupled between +3.3V and the input of power polarity controller  222 . 
     Voltage level translator  220  performs translation of signals from power polarity controller  222  to power sense controller  214  by coupling output signals from power polarity controller to the gate of a conventional p-FET, +3.3 volts to the source of the p-FET and coupling the drain of the p-FET to the input of power sense controller  214  via a 665 Ohm resistor. The input of power sense controller  214  is also coupled to −5.0 volts via a 1K resistor. 
     Power polarity controller  222  receives the polarity signal for a given port from power sense controller  214  and provides the proper signal to cause power polarity switcher  226  to cause the polarity of any power that can be supplied to that port to be either positive or negative, matching that indicated by the polarity signal received. In response to this signal, for each port, power polarity switcher  226  configures itself to enable itself to either pass the power it receives from 12 volt to −48 volt isolated inverter  252  with the polarity intact, or reversed, so that either 48 volt or −48 volt power is supplied to its outputs corresponding to that port based on the signal received from power polarity controller  222  for that port. In one embodiment, power polarity switcher  226  contains one or more conventional relays and need not contain more than one, because a single multicontact relay may be used. 
     This process will cause the polarity of the power that can be supplied by power polarity switcher  226  for each port to be configured to match the polarity requested by the user for that port as described above, however it does not cause such power to be supplied from power polarity switcher  226  to power output/network connector  232 . The process of supplying the power having the polarity configured as described above will now be described. 
     Application of Power to Ports 
     In one embodiment, power polarity controller  222 , power sense controller  214  or both, monitors the power connection at power output/network connector  232  to determine whether a device capable of properly drawing power from the Ethernet cable coupled to power output network connector  232  is coupled to power output network connector  232 . Such monitoring includes receiving signals, such as a valid detection signature, complying with the 802.3af specification that indicate that the device can receive power from an Ethernet cable, and may include checking for a lack of error conditions, such as open or shorted circuits as specified by the 802.3af specification. These conditions are collectively referred herein as the “power conditions”. 
     In one embodiment, power polarity controller  222  performs this detection and signals power sense controller  214  with an indication for each port as to whether a device was detected on that port that can properly draw power, for example, because the power conditions (valid signature, no errors) are all present. In another embodiment, power sense controller  214  performs this function by sensing via sense resistors  218  and provides and receives its own indication for each port. In still another embodiment, both techniques are used. 
     If the indication is received that a device that can properly draw power is detected on a port, power sense controller  214  causes the indicator of display indicators  216  that corresponds to that port to illuminate steadily in the color indicating the configuration, such as yellow for Cisco or IEEE-compatible −48 volt power and green for IEEE-compatible +48 volt power. If the indication is received that a device that can properly draw power is not detected on a port, power sense controller  214  causes display indicators  216  to flash in the color indicating the configuration, such as yellow for Cisco or IEEE-compatible −48 volt power and green for IEEE-compatible +48 volt power. 
     In the embodiment in which display indicators  216  are used to display both power and network status, power configuration status is provided as described above when no Ethernet connection is detected by wireless access manager  204 . When such connection is detected, wireless access manager  204  signals power sense controller  214  to cease its display of the power configuration, and power sense controller complies. Wireless access manager  204  then displays network status in a conventional manner using display indicators  216 . When the Ethernet connection is terminated, for example, because the Ethernet cable is removed from power output/network connector  232 , or when wireless access manager  204  identifies that no such connection is present as it monitors the system as described above, wireless access manager  204  signals power sense controller  214  to resume or continue its display of the power configuration as described above and power sense controller  214  complies. 
     When the power conditions are all favorably detected on a port, power sense controller  214  signals power polarity controller  222  for that port. Power polarity controller  222  signals power polarity switcher  226  to supply the power to the indicated port when so signaled by power sense controller  214 . 
     The signal received from power sense controller  214  instructing power polarity controller  222  to supply the power to the indicated port causes power polarity controller  222  to signal power FETs  224  to switch on for the indicated port. Power FETs  224  are conventional field effect transistors that can provide higher current than what may be available from power polarity controller  222  if necessary to drive power polarity switcher  228 . When power FETs  224  receive the signal described above for a particular port, power FETs  224  provide sufficient power to cause power polarity switcher  228  to supply at the output of power polarity switcher  228  the power with voltage having the polarity configured as described above. 
     When powered by power FETs  224  corresponding to a port, power polarity switcher  228  provides the power with the polarity configured as described above to the indicated port of power output/network connector  232 , which may contain one or more conventional Ethernet connectors, (e.g. one for each port). Power may be in the form of 48 volts or any other voltage, and as described above, may have either of the two polarities configured as described above, one polarity conforming to the IEEE standard described above, the IEEE standard having been developed by agreement of multiple organizations including multiple companies, and the other polarity conforming to the IEEE standard or to a standard developed by Cisco Systems, Inc. of San Jose, Calif. or another one or more corporations selling network equipment. 
     Power polarity switcher  228  provides the power to certain Ethernet cable leads (in one embodiment, these leads are the leads  236  not used for networking communication signals although in other embodiments, the leads are also used for signals) in power output/network connector  232  via optional chokes  238  (which can be used to reduce EMI emissions). In one embodiment, power output/network connector  232  contains, for each of four parts, a conventional RJ-45 or other conventional connector, such as one that can also be used to provide Ethernet signals, with leads  234  in each connector used to provide conventional communication signals, such as networking signals, which may be conventional Ethernet signals, received at network input  238 , as well as leads  236  in the same connector used to provide power. For each port, the power and networking signals are provided via a single cable plugged into power output/network connector  232  such as a cable of eight conductor, twisted pair wiring. 
     The above description was applicable to the case in which the valid detection signature and the lack of errors described above were detected by power polarity controller  222 . If a valid detection signature is not present or other errors are detected for a given port, power polarity controller  222  will indicate the problem and the port to power sense controller  214 , which will not direct power polarity controller  222  to apply power to power FETs  224  for that port. 
     In one embodiment, the power conditions are monitored at power leads  236  for each port as described above, and power sense controller  214 , power polarity controller  222 , or both, continue to monitor each port for open, short, or other error conditions. In the event that an error condition on a port is detected after power has been configured and supplied as described above, either power polarity controller  222  signals power sense controller  214  with an indication of the port, or power sense controller  214  performs such detection of any such error conditions for each such port. As a result, power sense controller  214  signals power polarity controller to stop applying power to power FETs  224  for that port, and power polarity controller  222  complies. This causes power polarity switcher  226  to disconnect the power it supplies to the corresponding port of power output/network connector  232  as described above. 
     As described above, power will be applied to power leads  236  for a port if the power conditions are met on that port, such conditions including detecting a valid power over Ethernet detection signature and not detecting error conditions such as short or open circuits and power will be maintained on that port if no error conditions are detected. In one embodiment, a user may cause power to be applied to, and/or maintained on, power leads  236  for a port even if some or all of the power conditions are not met on that port. Such a capability may be helpful in troubleshooting or when the conditions are thought either to be present, in spite of the fact that they have not been detected, or when the condition is not thought necessary to the application of power to power leads  236 . In such embodiment, a user may indicate to user interface manager  210  to ignore the lack of one or more (or all) of the power conditions for some or all ports, and user interface manager  210  communicates to power sense controller  214  such indication and the one or more port identifiers for which the indication corresponds. 
     If power sense controller  214  detects, and/or receives an indication from power polarity controller  222  that one or more of the power conditions has not been met, power sense controller  214  will only instruct power polarity controller  222  not to cause power polarity switcher  226  to apply or maintain power on a port as described above if the conditions that have not been met for that port correspond to those for which the user indicated were OK to ignore for that port. The indication to ignore may also apply to all conditions for a port, in which case, power sense controller  214  will instruct power polarity controller  222  to supply or maintain power for that port as described above even if none of the power conditions are detected by power sense controller  214  or power polarity controller  222 . 
     In one embodiment, user interface manager  210  internally stores in nonvolatile memory the configuration information received as described above. User interface manager  210  can utilize such information when it is restarted, for example, after a power failure, or may display the information and allow the user to apply it to the port or change it. 
     As noted above, power output/network connector  232  may include more than one physical connector, referred to herein as a “port”. For example, power output/network connector  232  may include four RJ-45 connectors, each of which may contain Ethernet leads  234  and power leads  236 . In such embodiment, the monitoring and control of the power described above is performed on a per-physical-connector basis. For example, if the power conditions are not detected in one connector, but detected in the others, power is not applied only to that one connector, but is applied to the other connectors. 
     Other Components 
     Wireless access manager  204  is a device that processes Ethernet communication signals and communicates with wireless devices, such as the conventional Vernier AM6500 commercially available from Vernier Networks, Inc. of Mountain View, Calif. In one embodiment, wireless access manager  204  provides Ethernet communication networking signals, such as corresponding to Ethernet communication networking signals it receives, to network input leads  238  of power output/network connector  232  via an internally located conventional Ethernet hub or switch. Network input leads  238  are coupled to Ethernet leads  234 , which supply communication signals to an Ethernet cable plugged into power output/network connector  232  and may be coupled to a conventional Ethernet switch, hub or other Ethernet equipment. The communication leads from wireless access manager  204  are coupled to power output/network connector  232  via a connection not shown to avoid cluttering the Figure. 
     The flow of information regarding power over Ethernet may be in the reverse direction in addition to, or instead of, the direction described above through isolator  212 . For example, if power sense controller  214  detects or receives an indication that one or more of the power conditions are not being met for a given port as described above, power sense controller  214  may provide this information to isolator  212 , which electrically isolates the information and provides it to power manager  202 , which generates and provides reports to a user via user interface manager  210 , and can indicate to other equipment such as wireless access manager  204  to take certain steps in response to the power information it receives. Such steps may include saving information to nonvolatile storage that is part of the other equipment such as wireless access manager  204  to allow for an orderly shutdown in the event of an error. 
     Referring now to  FIG. 3  (which is made up of  FIGS. 3A and 3B ), a method of configuring and providing power provided to a cable used for an Ethernet connection and for providing status information about such configuration is shown according to one embodiment of the present invention. Although Ethernet is used as described herein, any communication protocol such as a networking protocol may be used by the present invention.  FIG. 3  illustrates the method for a single port, and may be performed for each of several ports. 
     Referring now to  FIG. 3A , configuration information is received  310  as described above. The configuration information is electrically isolated  312  and provided  314 . The configuration information provided in step  314  is checked  316  to determine whether it corresponds to a first or a second configuration. If a change to the configuration of power to be supplied to any port has been made  318 , the method continues at step  320  and otherwise  318 , the method continues at step  340 . 
     At step  320 , if the configuration information corresponds to a first configuration  320 , such as a configuration corresponding to a communication industry-developed standard, a signal that will cause one or more relays or other similar switching devices to be placed into a first position is provided  322  and the first configuration is indicated  324 , such as by using the LEDs conventionally associated with status of the Ethernet connection at or near the connector from which power for that connection will be received or other LEDs as described above. The method continues at step  332 . 
     If the configuration information corresponds to a second configuration  320 , such as a configuration corresponding to a proprietary-developed standard, such as one developed by a single communications company, a signal that will cause one or more relays or other switching devices to be placed into a second position is provided  326  and the second configuration is indicated  328 , such as by using the LEDs conventionally associated with status of the Ethernet connection at or near the connector from which power for that connection will be received. The method continues at step  332 . 
     In one embodiment, steps  324  and  328  may be performed by flashing (or not flashing) such LEDs in a particular pattern, or using a particular flashing sequence (that does not indicate communications information flowing over the port used to receive the power) or color or set of colors to indicate the configuration and to indicate that the power conditions have not been detected as described above. 
     If the signal from steps  322  or  326  corresponds to the first position  332 , relays or other switching devices are positioned  334  to pass power with the polarity unchanged and the method continues at step  364 ; and otherwise  332 , the relays or other switching devices are positioned  336  to pass power with the polarity reversed (or vice versa). 
     Initial power conditions are detected  338  as described above. Such initial conditions are conditions detected before, or soon after, power is initially applied and may include the existence of a valid power over Ethernet detection signature or other conditions described in the power over Ethernet specification as described above. Other power conditions may be detected  340 , such as the nonexistence of short circuits or open circuits or other conditions that indicate that a device is capable of properly drawing power over an Ethernet cable. If the conditions detected in steps  338  and  340  are present  342 , the method continues at step  344  and otherwise  342  the method continues at step  350 . At step  344 , power, received as described in steps  360 – 370  of  FIG. 3B  and configured as described above, is transferred from the input to the output of a relay or other device. Step  344  may include boosting a signal using a transistor such as a conventional FET that supplies power to the relay or other device as described above. 
     The power transferred in step  344  may be filtered and provided to a network connector, such as a conventional RJ-45 Ethernet connector that may also simultaneously carry networking signals, as described above  346 . An indication that power is being supplied to the network connector and that the power conditions are present is provided, such as via an LED as described above  350  and the method continues at step  316 . 
     At step  350 , if any of the conditions detected in steps  338  or  340  are not present  342 , if an override indication for the condition not present or for all conditions has been received as described above, the method continues at step  344  and otherwise  350 , the transfer of power through the relay or other device is discontinued and an indication of the power configuration and the fact that power is not being provided or that the power conditions are not met is provided as described above  352 . In one embodiment, if the yes branch of step  350  is taken, the indication is changed to indicate that the power conditions are not being met in step  348  instead of indicating that the conditions are present as described above. 
     Referring now to  FIG. 3B , power is received  360  and filtered  362 , isolated and its voltage may be converted and the converted, isolated voltage provided  364 , and the isolated, converted power may have its voltage converted and provided  366  and converted and provided again  368  as described above. 
     The power, isolated, filtered, converted, and provided in any of steps  360 – 368 , such as that provided in step  364 , is provided to relays or other switching devices configured in steps  334  or  336  and the method continues at step  344 . 
     Referring now to  FIG. 4 , a method of providing status information about power provided via the same port as that used for an Ethernet connection is shown according to one embodiment of the present invention. 
     Power is provided  410  to a port such as a conventional Ethernet connector or other connector that also serves to pass Ethernet signals. Information related to the power provided in step  410  is detected  412  as described above and the power information is provided  414  to a device that can electrically isolate it. The power information is received  416  at the device, which electrically isolates  418  the power information and provides the electrically isolated power information  420 .