# Patent

## Title
Patch field documentation and revision systems

## Abstract

A communication network device and corresponding patch field system are disclosed. The device includes a port module, ports, and an appliqué attached to a face of the port module. The appliqué includes a printed circuit board (PCB) with conductive pads. A patch cord connects the device with an intelligent patch panel. The patch cord contains at least one system wire. The patch panel is adapted to measure a resistance associated with each port via the system wire. An open circuit indicates that no patch cord is attached to the port, a resistance within a first range indicates that the patch cord is attached only to the port of the intelligent patch panel, and a resistance within a second range less than the first range indicates that the patch cord connects the intelligent patch panel and the device.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. patent application Ser. No. 11/467,330, filed on Aug. 25, 2006 which claims priority to U.S. Provisional Application Ser. No. 60/711,960, filed on Aug. 26, 2005; both applications are entitled “Patch Field Documentation and Revision Systems” and are incorporated by reference herein in their entireties.


TECHNICAL FIELD
The present invention relates to documentation systems and more particularly relates to a system for documenting and revising patch cord connections in a communications network patch field.
BACKGROUND
Patch panels are used in communications networks as intermediate elements between horizontal cabling (to which endpoint devices such as computers and telephones are connected) and network switches. When physical connections between endpoint devices and network switches are moved, added, or changed, patch panels are the points at which technicians complete the required moves, additions, or changes of cabling within patch fields. It is important to keep track of changes that are made to patch cord connections within the patch field. Proper documentation of changes in the patch field assures that the routing of patch cords is always known and further assures that any future changes are completed correctly.
In interconnect network configurations, one patch panel is placed between the horizontal cabling and the network switch. In an interconnect configuration, the documentation of patch cord connections between the patch panel and the switch will provide the necessary documentation of connections between the switch and the horizontal cabling. In cross-connect network configurations, two patch panels are placed between the horizontal cabling and the network switch. In a cross-connect configuration, the documentation of patch cord connections between the two patch panels will provide the necessary documentation of connections between the switch and the horizontal cabling. It is desirable to have a patch cord management system that will support both interconnect and cross-connect configurations. It is also desirable for a patch cord management system to have a minimal impact on existing networks.
SUMMARY OF THE INVENTION
According to one embodiment of the present invention, a patch cord management system supports patch cord management in communications networks having an interconnect configuration. In one embodiment, appliqués are applied to network switches—such as Ethernet switches—to provide for the management of patch cord connections between an intelligent patch panel and the network switch.
In one embodiment, indicator lights are provided to guide the installation and management of patch cord connections. Each network switch port that is connected to an intelligent patch panel is uniquely identifiable by the intelligent patch panel.
According to another embodiment of the present invention, a patch cord management system supports patch cord management in communications networks having a cross-connect configuration.



BRIEF DESCRIPTION OF FIGURES
FIG. 1 is a block diagram of an intelligent patch panel and a network switch in a network having an interconnect configuration;
FIG. 2 is an upper left side view of a plug for a 10-wire patch cord with two pogo pins;
FIG. 3 is block diagram of a patch cord connection in a patch cord management system according to one embodiment of the present invention;
FIG. 4 is a perspective view of a switch port module with an appliqué;
FIG. 5 is an exploded perspective view of a switch port module with an appliqué;
FIG. 6 is a front view of a switch port module with an appliqué;
FIG. 7 is a detail view of the detail “A” of FIG. 6;
FIG. 8 is a cross-sectional view along the line “B-B” of FIG. 7;
FIG. 9 is a cross-sectional view along the line “C-C” of FIG. 7;
FIG. 10 is a cross-sectional view along the line “D-D” of FIG. 7;
FIG. 11 is a schematic diagram of a port identification circuit;
FIG. 12 is a block diagram showing multiple port identification circuits for an Ethernet switch;
FIG. 13 is a schematic diagram of a patch cord system pair connection in a patch field documentation and revision system; and
FIG. 14 is a block diagram of intelligent patch panels and a network switch in a network having a cross-connect configuration.



DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The present invention is directed to methods and systems for documenting and guiding patch cord changes in a patch field of a communications network. FIG. 1 shows a preferred embodiment, in which an intelligent patch panel 10 and a network switch 12 in a communications network are connected in an interconnect configuration. This embodiment provides real-time documentation which is reliable under all conditions and it provides an efficient indicator light system on all patch panel and switch ports (jacks) to guide technicians when installing or removing patch cords. In the embodiments shown and described herein, the network switch is an Ethernet switch, but it is to be understood that the present invention can be applied to other types of networks.
A patch cord 14 connects a port on the switch 12 to a port on the intelligent patch panel 10. Horizontal cabling 16 connects the intelligent patch panel 10 to endpoint devices, such as computers and telephones.
In a preferred embodiment as illustrated in FIG. 2, the patch cord 14 is a ten-wire patch cord. Eight of the wires comprise a standard four-pair Ethernet channel corresponding to the standard plug contacts 18 on the plug 20. The ninth wire and the tenth wire terminate at first and second pogo pins 22 and 24, respectively, for connection to contacts provided on intelligent patch panels and on switches. The pogo pins are provided in a pogo pin module 26 which is asymmetrically positioned to allow for situations where the jacks on a switch are vertically adjacent each other (for example, in a 2×24 arrangement).
FIG. 3 shows a patch cord 14 installed between an intelligent patch panel 10 and an Ethernet switch 28 in a system that allows for patch cord documentation and revision in the patch field 30 between the intelligent patch panel 10 and the Ethernet switch 28. Patch cord documentation and revision is enabled because each Ethernet switch 28 (or group of ports on an Ethernet switch) is assigned a unique identifier code, and each port 34 on that Ethernet switch 28 (or within that group of Ethernet switch ports) is assigned a sequential port number (i.e. 1-24 or 1-48). A similar identification procedure is used for each intelligent patch panel or group of ports on an intelligent patch panel. Thus, each switch port 34 that is connected to an intelligent patch panel 10 is provided with a unique identifier code.
The group of switches and the patch panels to which they are connected are assigned a unique identifier and this is transmitted along with the patch panel group, switch group, and port I.D.s of ports in the group to a Network Management System (NMS) by an intelligent patch panel.
The patch cord 14 comprises four signal pairs 36 and one system pair 38 consisting of the ninth and tenth conductors. The signal pairs 36 provide standard Ethernet signal connectivity. The system pair 38 enables the intelligent patch panel 10 to send signals to electronic components positioned on the face of the Ethernet switch 28. These electronic components may be provided on printed circuit boards (PCBs) provided in appliqués that are attached to the face of the Ethernet switch 28. A resistor 40 with a high resistance is placed across the system pair 38 of the patch cord 14. In the embodiment of FIG. 3, the resistor is placed within a plug of the patch cord 14.
The system pair 38 makes contact via probes 42 with conductive pads 45 and 47 on the face of the intelligent patch panel 10 and with conductive pads 46 and 48 on an appliqué 44 attached to the Ethernet switch 28. The probes 42 may be pogo pins, as discussed above. The probes 42 complete an electrical circuit between a PCB in the intelligent patch panel 10 and a PCB in the appliqué 44 when the patch cord 14 is installed between the patch panel port 32 and the switch port 34. The PCB in the intelligent patch panel 10 may include a port interface module 49, which implements the functions of the intelligent system as further discussed below.
Installation and/or revision of the plugs 20 of inter-connect patch cords 14 is preferably guided by a wireless portable PC (a work order PC) which provides work orders in sequence to the responsible technician.
When a patch cord 14 is installed, one plug is plugged into the intelligent patch panel 10 with the guidance of an indicator light adjacent the correct port. An indicator light adjacent to the port to which the patch cord was connected communicates to the technician that this step was correct or incorrect. This portion of the system is the Patch Panel Plug Presence System.
When the other end of this patch cord 14 is plugged into a switch port 34, the intelligent system in the intelligent patch panel 10 detects this step and an indicator light adjacent to the port which the patch cord was connected to will communicate to the technician that this step was correct or incorrect. This portion of the system is the Switch Plug Presence System.
The patch cord removal guidance is similar to the above.
When a patch cord 14 is installed, an intelligent system in the intelligent patch panel 10 monitors the connection between the two ports 32 and 34 in real time. If the patch field 30 was newly installed or if the system operation was temporarily interrupted, the system immediately determines the documentation of the interconnect patch field 30. This documentation is therefore completely reliable and in real time.
Each intelligent patch panel 10 includes circuits and circuit components which accomplish all the above and which communicate with an NMS via Ethernet signals through a switch. According to one embodiment, the only electrical connections to each intelligent patch panel 10 (other than patch cord connections) are the four-pair Ethernet cable for connection to the NMS and a power cord.
Turning now to FIG. 4, a perspective view of a switch module 43 with an appliqué 44 is shown. The switch module 43 has twelve switch ports 34, but it is to be understood that the present invention may be scaled for use with switch modules having fewer or more ports. The appliqué 44 has first and second conductive pads 46 and 48 for each switch port 34. The conductive pads 46 and 48 are conductively connected to switch port identification circuits 50 as described below with reference to FIGS. 11-13. As shown in FIG. 4, the appliqué 44 may be attached to a switch port module 43 by clips 60 formed in a frame 62.
FIG. 5 is an exploded view of the appliqué 44 attached to the switch module 43. The appliqué 44 comprises three main parts: a frame 62, a circuit board 64, and a cover 66. The frame 62 is preferably constructed of metal and is provided with mounting tabs 68 for retaining the circuit board 64 and the cover 66. Reflectors 70 are formed in the frame 62 to optically isolate the LED modules 55 from one another. This assures that light emitted from upper or lower LED modules 55 are not mistakenly associated with wrong switch ports 34 by a technician. The circuit board 64 has the conductive pads 46 and 48 as well as the LED modules 55 and the other circuitry for the switch port identification circuits 50 (as shown in FIGS. 11 and 12). The circuit board 64 has circuit board apertures 65 to accommodate the reflectors 70. The cover 66 is preferably constructed of a clear material and is provided with cover apertures 72 to allow probes 42 of patch cords to make contact with the conductive pads 46 and 48 on the circuit board 64. According to one embodiment, the appliqué 44 is constructed by positioning the circuit board 64 between the cover 66 and the frame 62 and bending the mounting tabs 68 into the mounting positions shown in FIG. 5, holding the circuit board 64 between the cover 66 and the frame 62.
FIG. 6 is a front view of a switch module 43 with an appliqué 44 mounted thereon. FIG. 7 is a detail view of the detail “A” of FIG. 6. According to an embodiment utilizing the plug 20 of FIG. 2, the first and second conductive pads 46a and 48a on the left side of the view of FIG. 7 are associated with the lower switch port 34a. The first and second conductive pads 46b and 48b on the right side of the view of FIG. 7 are associated with the upper switch port 34b. Also shown in FIG. 7 are bi-color LED modules 55a and 55b, respectively associated with the lower and upper switch ports 34a and 34b. The reflector 70 separates the bi-color LED modules 55a and 55b. FIGS. 8, 9, and 10 are cross-sectional views along the lines B-B, C-C, and D-D, respectively, of FIG. 7. The cross-sectional view of FIG. 8 shows the first conductive pad 46a. The cross-sectional view of FIG. 9 shows the bi-color LED modules 55a and 55b and the reflector 70. The cross-sectional view of FIG. 10 shows the mounting tabs 68 of the frame 62 bent over the cover 66.
As further discussed below with reference to FIGS. 11-13, the conductive pads 46 and 48 on the appliqué 44 are connected to signature resistors having different values of resistance corresponding to individual switch ports. The signature resistors have unique values corresponding to each switch port or each group of switch ports. The intelligent patch panel 10 continuously makes resistance measurements across the system pair 38. If an open circuit is measured, this implies that no patch cord 14 is attached to the intelligent patch panel. If a high resistance is measured, this implies that the patch cord 14 is only attached to the intelligent patch panel 10. If a resistance within the range of the resistance values of the signature resistors in the appliqué 44 at the Ethernet switch 12 is measured, this implies that both ends of the patch cord 14 are attached.
Turning to FIGS. 11 and 12, switch port identification circuits 50 are shown. The switch port identification circuits 50 comprise light-emitting diodes (LEDs) 52 and 54 (which may be implemented as bi-color LED modules 55), port signature resistors 56, and panel signature resistors 58. In one embodiment, LED 52 is red and LED 54 is green. The panel signature resistors 58 may indicate the switch panel corresponding to each port, or they may be substituted for signature resistors indicating particular switches or switch groups containing each port. According to one embodiment, each switch module in a switch is provided with a different signature resistor. In this embodiment, the signature resistors 58 would not be panel signature resistors, but rather would be switch module signature resistors. When measuring the port signature resistors 56, a forward bias is applied to the ninth wire and the resistance is measured. When measuring the panel signature resistor 58 (or other associated group signature resistor), a reverse bias is applied to the ninth wire and the resistance is measured. FIG. 12 is a block diagram showing the switch port identification circuits 50 associated with each port of a 48-port switch. Conductive pads 46 and 48 are also shown.
In one embodiment, a constant current source in the intelligent patch panel is used to light revision lights for the revision system to provide uniform illumination.
According to one embodiment, the revision light system for each patch panel port is as follows:













Green solid:
Install plug


Green off:
Installed correctly


Red pulsating:
Plug was installed in wrong port; remove


Red off:
Removed correctly


Green pulsating:
Remove plug


Green off:
Removed correctly


Red solid:
Adjacent plug was removed erroneously; reinstall


Red off:
Adjacent plug reinstalled correctly









The revision light system for each switch port is as follows:













Green solid:
On for time delay after correct installation


Red pulsating:
Plug was added to wrong port; remove


Green pulsating:
Remove plug


Yellow pulsating:
Wrong plug was removed; replace plug which was


(Light that was
erroneously removed; when replaced, yellow pulsating


green changed
light changes to green pulsating.


to yellow)









The yellow indicator light is obtained by the combination of the red and green indicator lights. According to one embodiment, an audible alarm may be initiated by an intelligent patch panel to indicate to the installer that a wrong operation was performed (for example, if an incorrect plug was removed from an Ethernet switch port).
When an error in plug installation or removal has occurred, the system provides an indicator light and/or audible alarm from the associated patch panel. An alarm notice and details of the error and remedy are provided on the work order PC. No further revision steps are ordered until the error has been corrected.
It should be noted that a switch jack light will not guide the installation of a plug to the switch 12 because the power for the light is supplied through the patch cord 14. However, if a plug is correctly installed, a green indicator light will turn on for a time delay. If a plug is installed in an incorrect port, a flashing red indicator light adjacent to that port will stay on until the plug is removed. Such a temporary incorrect patch cord connection should not be detrimental because that incorrect switch port should not be energized.
FIG. 13 is a schematic diagram of a patch cord system pair connection between a port interface module 49 of an intelligent patch panel and a port identification circuit 50 located at an Ethernet switch port. The port interface module 49 is connected via conductive pads 45 and 47 to probes 42 of the system pair 38 of the patch cord. The system pair 38 of the patch cord is further connected to the conductive pads 46 and 48 at the switch port. The port interface module 49 implements the functions necessary to support the intelligent system of the intelligent patch panel 10. According to one embodiment, the port interface module 49 comprises circuitry to implement three functions of the intelligent system of the intelligent patch panel: (a) detecting the presence of a plug in the intelligent patch panel; (b) identification of Ethernet switch ports and detection of the presence of plugs in the switch ports; and (c) powering indicator lights at the Ethernet switch ports. Detection of plug presence in the patch panel ports and switch ports and identification of Ethernet switch ports are preferably accomplished using AC signals generated by the port interface module 49. The resulting response signals are detected by the port interface module 49, allowing plug detection and Ethernet switch port identification. LEDs 52 and 54 in the port identification circuit 50 may be powered by the port interface module 49, either one-at-a-time or simultaneously, via pulsed DC or AC. A capacitor 74 protects the circuitry of the port interface module 49 from high voltages that might be placed across the system pair 38 of the patch cord.
Systems and methods according to the present invention may be adapted for use in a cross-connect network. In the cross-connect embodiment as shown in FIG. 14, in which the relevant patch field 30 is between two intelligent patch panels 10a and 10b, the same patch cords 14 as described above are used between the intelligent patch panels 10a and 10b. The plug presence part of the above-described system is utilized, providing this benefit without the need for additional dedicated plug sensors. However, the documentation portion of this system may be as described in U.S. patent application Ser. No. 11/265,316 and U.S. Provisional Patent Application Serial No. 60/624,753. In this embodiment, each patch panel communicates with a control system via Ethernet signals.
Other embodiments can accomplish the goals of the present invention utilizing different circuit elements (e.g., resonant circuits providing frequencies associated with port/panel identification information) or chips (e.g., I.D. chips). In addition, other embodiments utilize local power and/or a signal and/or ground connections to each switch PCB. The number of system wires in each patch cord and the number of plug probes could also vary. For example, in one alternative embodiment foregoing plug detection at the patch panel, one system wire and system grounding are used in place of two system wires for switch port identification. In alternative embodiments, the switch can be replaced with a patch panel, with an appliqué being applied to the patch panel.

## Claims

1. A network device comprising a printed circuit board (PCB) and a plurality of ports, each of the ports adapted to receive a patch cord, the PCB adapted to provide a plurality of port signature resistances and a panel signature resistance, the port signature resistance associated with a particular port unique to the particular port, the panel signature resistance associated with the particular port dependent on a group of ports to which the particular port belongs, the group of ports containing at least two of the plurality of ports.

2. The network device of claim 1, further comprising:
a plurality of LED modules, each LED module adjacent to a different port and containing an LED; and
a reflector disposed between adjacent LED modules such that the reflector optically isolates the adjacent LED modules from one another.

3. The network device of claim 2, wherein the adjacent LED modules are aligned vertically, a center of the reflector is aligned vertically with centers of the adjacent LED modules, and the reflector extends horizontally in both directions farther from the center of the reflector than the LEDs of the adjacent LED modules extend from the center of the adjacent LED modules.

4. The network device of claim 2, wherein power for the LEDs is carried by a patch cord such that the LED associated with a particular port is able to be illuminated only if a patch cord is connected to the particular port.

5. The network device of claim 1, wherein:
each port signature resistance is provided by an individual port signature resistor, and
the PCB is adapted to provide a plurality of panel signature resistances, each panel signature resistance provided by an individual panel signature resistor.

6. The network device of claim 1, wherein:
each port signature resistance is provided by an individual port signature resistor,
the panel signature resistance is provided by a panel signature resistor, and
the same panel signature resistor is associated with each of the ports.

7. The network device of claim 1, wherein the PCB comprises:
a plurality of port signature resistors, each port signature resistance provided by one of the port signature resistors,
a panel signature resistor that provides the panel signature resistance, and
a plurality of diodes connected to the port and panel signature resistors such that, of the port and panel signature resistors, only the port signature resistor is measurable when a first voltage is applied and only the panel signature resistor is measurable when a second voltage of opposite polarity to the first voltage is applied.

8. The network device of claim 7, wherein:
the PCB comprises a port identification circuit that contains different color LEDs, and
the port identification circuit is configured such that a series combination of the port signature resistor and an LED of a first color is connected in parallel with a series combination of the panel signature resistor and an LED of a second color.

9. The network device of claim 1, wherein the PCB further comprises a plurality of pairs of externally accessible conductive pads, each pair of conductive pads adjacent to and associated with a particular port, each pair of conductive pads connected with the port and panel signature resistances of the associated port such that the port and panel signature resistances of the associated port are measurable by connection to the pair of conductive pads.

10. The network device of claim 9, wherein the pair of conductive pads associated with a particular port is vertically adjacent to the particular port such that the pair of conductive pads is asymmetrically positioned with respect to a vertically-extending centerline of the particular port, adjacent pairs of conductive pads associated with vertically adjacent ports overlapping horizontally.

11. A network device comprising:
a plurality of ports, each of the ports adapted to receive a patch cord;
a plurality of LED modules, each LED module adjacent to a different port and containing an LED;
an optical isolator disposed between adjacent LED modules such that the optical isolator optically isolates the adjacent LED modules from one another; and
a printed circuit board (PCB) containing the LED modules, each LED module containing a plurality of different color LEDs, the PCB adapted to control the different color LEDs to display to which port a patch cord is to be inserted or removed and whether the patch cord has been inserted or removed correctly using different colors and LED display modes.

12. The network device of claim 11, wherein the optical isolator comprises a plurality of individual reflectors.

13. The network device of claim 12, wherein:
the adjacent LED modules are aligned vertically,
each reflector isolates a pair of vertically adjacent LED modules,
a center of each reflector is aligned vertically with centers of a particular pair of vertically adjacent LED modules associated with the reflector, and
each reflector extends horizontally in both directions farther from the center of the reflector than the LEDs of the adjacent LED modules associated with the reflector extend from the center of the adjacent LED modules associated with the reflector.

14. The network device of claim 12, further comprising:
a frame from which the reflectors extend;
a printed circuit board (PCB) containing the LED modules, the PCB having apertures adjacent to the LED modules and through which the reflectors pass; and
a cover covering the LED modules and the reflectors, the cover comprising a clear material that permits the LEDs to be visible externally.

15. The network device of claim 14, further comprising an appliqué attached to a face of the network device between sets of vertically adjacent ports, the appliqué containing the frame, the PCB, and the cover.

16. The network device of claim 11, wherein power for the LEDs is carried by a patch cord such that the LED associated with a particular port is able to be illuminated only if a patch cord is connected to the particular port.

17. The network device of claim 11, further comprising a printed circuit board (PCB) that contains a plurality of pairs of externally accessible conductive pads and the LED modules, each pair of conductive pads adjacent to and associated with a particular port.

18. The network device of claim 17, wherein the pair of conductive pads associated with a particular port is vertically adjacent to the particular port such that the pair of conductive pads is asymmetrically positioned with respect to a vertically-extending centerline of the particular port, adjacent pairs of conductive pads associated with vertically adjacent ports overlapping horizontally.

19. A method of managing a patch field system, the method comprising:
providing a network device having a plurality of network device ports and a printed circuit board (PCB) with a plurality of pairs of PCB conductive pads, each pair of PCB conductive pads associated with a different network device port;
providing a patch panel having a plurality of patch panel ports and a plurality of patch panel conductive pads, each pair of patch panel conductive pads associated with a different patch panel port; and
the patch panel measuring a resistance associated with one of the patch panel ports using the pair of patch panel conductive pads associated with the one of the patch panel ports, a measurement in a first resistance range indicating that no patch cord is attached to the one of the patch panel ports, a measurement in a second resistance range indicating that a patch cord is attached only to the one of the patch panel ports, a measurement in a third resistance range indicating that a patch cord is connected between the one of the patch panel ports and one of the network device ports.

20. The method of claim 19, further comprising determining to which network device port the one of the patch panel ports is connected using the resistance measured, each of the network device ports having a port signature resistance unique to the network device port and a patch panel signature resistance dependent on a group of network device ports to which the network device port belongs, the group of network device ports containing at least two of the plurality of network device ports.

21. The method of claim 20, further comprising:
permitting measurement of the port signature resistance of the one of the network device ports when a first voltage is applied to the pair of patch panel conductive pads associated with the one of the patch panel ports but not when a second voltage of opposite polarity than the first voltage is applied; and
permitting measurement of the patch panel signature resistance of the one of the network device ports when the second voltage is applied to the pair of patch panel conductive pads associated with the one of the patch panel ports but not when the first voltage is applied.