Termination cap for use in wired network management system

A termination unit (144) for use with a system that permits the monitoring of a computer network to perform network inventories. The termination unit takes the form of a cap that engages the termination face of a network jack and has a sensing circuit (246) integrated therewith so that, once engaged with the jack, the sensing circuit is connected to two terminals of the jack. The sensing circuit may include a resistor, capacitor or inductor, any of which provide a known sensing value that is different than a sensed value of an end-user device used on the network, but less than infinity so that the system senses when an end-user device is connected to or disconnected from the network.

BACKGROUND OF THE INVENTION

The present invention relates generally to infrastructure management systems and, more particularly, to systems, assemblies and components that are useful in managing infrastructure assets.

Computing networks that exist within large organizations consist of two types of devices that must be inter-connected to form a usable data network. These devices, which are also referred to in the art as assets, are generally classified as end-user devices and networking devices. Examples of end-user devices include personal computers (PC), voice-over-internet protocol (VoIP) phones, and network printers. A typical Local Area Network (LAN) for a large-scale enterprise may include thousands of end-user devices deployed throughout a campus in individual offices or in common areas accessible to the end-users. In addition, data networks also typically include network devices such as switches and routers that form the core of the network. These networking devices serve to route data packets between network devices on the LAN, or between the LAN and the larger corporate Wide Area Network (WAN), or to the internet. These network devices are typically located in a centralized room or rooms, known as wiring closets and data centers.

Information technology (IT) departments for such organizations need to know the status of network connectivity of each end-user device, the physical location of the end-user devices, and need to identify the source and location of any errors or problems as quickly as possible. Tracking of end-user devices is a key concern—for example in monitoring the presence of end-user devices on the network for loss-prevention purposes, or to ensure end-user devices are properly physically positioned in offices or on floors where end users can best utilize them, while maintaining proper connectivity of the network. Currently, a unified system for tracking end-user devices connected to the network and monitoring the status of the physical connectivity of the network does not exist.

The Open System Infrastructure (OSI) model describes layered communications in a computer network. “Layer 1,” the physical layer, defines all of the electrical and physical specifications for network and end-user devices connecting to a network. For example, the Institute of Electrical and Electronics Engineers (IEEE) Standard 802.3 defines the standards for wired Ethernet, which is commonly used in computing networks. As part of the IEEE 802.3 Specification, the physical layer of an Ethernet network is defined. Examples of physical layer elements as defined in IEEE 802.3 include electrical voltages and signal protocols, cable requirements, and termination resistance.

To connect the end-user devices to the network devices requires that the network devices in the wiring closet or data center be connected to end-user devices as needed for the particular requirements of the users of the LAN. Each path from switch to end-user device is known as a channel. The typical deployment of physical layer connectivity for a LAN channel consists of a patch cord between a switch port and a patch panel port; a length of multi-pair cable from the rear of the patch panel port to a work area outlet port at the end-user's office, and a patch cord from the outlet to the end-user's device. Each of these ports are modular jacks designed to industry-standard specifications so as to accept mating patch plugs.

The management of the patch cords in the telecom room or at the work area outlet can present issues to the IT management group. Each time an employee is hired, leaves the organization or changes location, it is inevitable that patch cables must be connected and disconnected. A wiring closet typically contains numerous switches, patch panels and patch cords, numbering at times in the hundreds and higher. The patch cords are often snaked around one another, making the operations of adding, removing, or tracing the patch cords difficult and time-consuming. When a new patch cable has to be connected within the system, or a patch cable has to be moved, a technician enters the wiring closet and must locate the appropriate cable among hundreds, or perhaps thousands, of patch cords. The technician then must locate the appropriate patch panel and the appropriate ports on those patch panels. Finally, the technician must connect the patch cord to the correct ports on the patch panels and verify that the connection has been done correctly. Once the patch cord is connected, there is not an easy, cost and time-effective way to determine if the cord was connected to the correct port(s). For example, the technician may have to go to the network port or end-user device located at a remote location, such as an individual's office, to determine if the patch cable was correctly inserted and that network connectivity is available at the asset. Therefore, connecting and transferring networks assets is labor-intensive.

Additionally, the IT department does not have an efficient way to determine the exact location of network problems which may be attributed to the physical layer. For example, the problem may be located in the switch closet if a patch cord was not properly connected, or the problem may exist in the wiring from the switch closet to the end-user device. The IT department does not currently have an efficient way to determine if network problems exist in the physical network wiring. Accordingly, a need exists for a better information management system that includes components that simplify the process for identifying end-user devices in order, at a minimum, to reduce the time required to move and check end-user devices on a network.

An additional area of concern is that the LAN may have substantial numbers of unused or spare permanent links. A spare permanent link refers to a cable connection from patch panel to a work area outlet, but without a network device and/or end-user device connected via patch cords. Such links are typically maintained in LAN deployments to ensure appropriate capacity in case of employee moves, adds or changes, or to ensure extra capacity for disaster-recovery scenarios. An issue facing IT managers today is that it is difficult and time consuming to re-test spare permanent links to verify connectivity prior to their being put into use. Consequently most spare permanent links are not tested on a regular basis, and if there is a problem with the connectivity of the link, the issue may not be discovered until the permanent link is activated as part of a working channel. This can cause delay and added expense as the problem is tracked down and repaired.

U.S. Pat. No. 6,590,374, issued Jul. 8, 2003 to Har-Lev describes a terminator unit for use in wiring networks for naming outlets and for verifying the normality of the wiring. The terminator includes a connector with a plurality of contacts and a set of resistors. The resistors of the first set are connected between a common point and a selected contact, such that a particular binary code is determined according to the particular combination of resistors connected to the contacts.

Periodic probing or polling of all ports on the network is performed in order to list, or catalog, all of the connected end-user devices order to develop an inventory of the same. Assembling this inventory requires “pinging” every connection port on the network and gathering data from the connected end-user devices. This network intensive process is typically performed not more than once per month in order to limit disruption to the network. Accordingly, a system that is capable of providing up-to-date information whenever an end-user device is connected to the network without more frequent system-wide polling is desirable.

SUMMARY OF THE INVENTION

Accordingly, it is a general object of the present invention to provide an improved system for monitoring a network having multiple work area outlets to which are connected various end-user devices, the system facilitating the inventorying of the network and monitoring the end-user devices.

Another object is to provide a termination unit for use in a system that monitors a wired computing network having a plurality of end-user devices, the termination unit including a cap portion that is configured to matingly engage a termination face of a work area outlet that is connected to the computing network, the cap portion including at least one electronic element supported thereby having a specific measured value by which a change in the impedance of the system can be measured and forming a parallel system circuit with the network cable, and the cap portion further including at least a pair of terminals that contact opposing terminals of the work area outlet so as to complete the parallel circuit when the cap portion is mated with the network jack.

Yet another object is to provide a termination cap for use in a wired computing network having a plurality of work area outlets, wherein the termination cap includes an insulative housing, a substrate supporting a resistive element disposed in a resistance circuit thereon and at least two terminals extending therefrom for mating with corresponding opposing mating terminals of a termination face of the work area outlet, the termination unit including a plurality of engagement members projecting therefrom in opposition to slots formed on the termination face of the work area outlet, the terminals of the termination cap being aligned with the engagement members so as to be shielded thereby and the terminals being aligned with two selected terminals of the work area outlet so as to connect the resistance circuit to the work area outlet in parallel.

A still further object is to provide a termination cap for use with a data or computer network having a system for monitoring the presence of end-user devices connected to the network, the termination cap including a sensing element, or circuit, that connects with selected terminals of two distinct differential signal wire pairs of a work area outlet, the sensing element having a preselected sensing value that affects the impedance of the system, such that when the termination cap is connected to the work area outlet, there is a first sensing value in the network cable leading to the work area outlet, which is different than infinity and is different than the sensing value of the end-user device, and which may be read remotely at the work area outlet by a scanner to thereby determine whether or not an end-user device is connected to the work area outlet, thereby providing the monitoring system with a means for determining when an end-user device has been attached to the network at a specific location on the network.

Yet another object is to provide a method for monitoring the work area outlets of a data communication network for connectivity by providing a series of work area outlets interconnected as a network, and connecting network cables to the work area outlets and providing a termination unit for each work area outlet that terminates two of the wires of the each network cable, with a resistance circuit of a given value, arranged in parallel with the work area outlet, and then monitoring the work area outlet for a change in impedance which results when a device is connected to or removed from the work area outlet.

These objects and advantages are accomplished by way of the structure of the termination cap. The jacks used in the systems of the inventions utilize insulation displacement terminals that are disposed along a rear, or terminating face of the jack. A termination unit, or cap is provided that mates with the rear insulation displacement terminals of the jacks used in the work area outlet. The termination cap preferably includes a resistive element supported on a substrate which defines resistance circuit. Two conductive terminals are supported by the termination unit and are located in the termination unit so as to intersect or make contact with two of the insulation displacement terminals on the jack terminating face. The terminals are arranged so that they will contact terminals terminated to two distinct differential signal wires pairs, and not contact any terminals which are terminated to a differential signal wire pair. As such, the connection is made between pairs and not within pairs. In this manner, the termination unit of the present invention utilizes the existing wiring of a network and does not require a ninth wire or a proximity switch within the work area outlet as do some monitoring systems.

The terminals of the termination unit have a depth sufficient to make contact with the terminals, but not large enough to cause the insulation displacement terminals to spread apart and possibly destroy the integrity of the connection with the wires of the network cable. The terminals lead to circuitry on a substrate supported by the termination unit which includes a electronic element, having a preselected measured value that when connected to the network, will change the impedance of the cable and/or work area outlet. The electronic element will typically be chosen from the group consisting of resistors, capacitors, inductors and combinations of the same. Typically, the electronic element is chosen as a resistive element. The value of this resistive element is chosen such that it is greater than the impedance of an Ethernet end-user device, which is about 150 ohms, and it is less than the resistance of an open circuit, namely infinity. The terminals make contact with the wires of two distinct differential signal pairs so that a parallel path resistance circuit is provided, so that when the work area outlet has no end-user device connected to it, the system will read the resistance of the termination unit, and when an end-user device is connected to the work area outlet, the system will read the resistance of the end-user device.

Although in the preferred embodiment, resistive elements are used and the sensing value used is the resistance value of the system, other electronic elements that affect the impedance of the system, such as capacitors, inductors, a combination of the two or all three may be used to provide similar results. All such elements will affect the impedance of the system, including the network cables and will complete parallel circuit paths when the termination cap is terminated, thereby changing the value of the sensing element to a distinct, measurable value for indicating another condition of the network. When incorporated into a termination cap, the termination cap becomes connected to various connection points of the network, the connectivity and status of which may now be measured. These connection points are chosen by the network designer where there is interest in confirming the presence of a network cable or patch cord.

These and other objects, features and advantages of the present invention will be clearly understood through a consideration of the following detailed description.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description is intended to convey the operation of exemplary embodiments of the invention to those skilled in the art. It will be appreciated that this description is intended to aid the reader, not to limit the invention. As such, references to a feature or aspect of the invention are intended to describe a feature or aspect of an embodiment of the invention, not to imply that every embodiment of the invention must have the described.

Turning to the drawings and referring first toFIG. 1, a typical computing, or data transmission, network100is illustrated to show the environment in which the patch panel assemblies of the present invention are used. An example of such a data network is a corporate electronic computing network with multiple users and network and end-user devices connected thereto by which network users can access, exchange and store data. As used herein, the term “end-user device” refers to a physical item that is connected to a work area outlet and which can be operated by any user of the network and may include, without limitations, a personal computer, telephone, printer, facsimile machine, monitor or other devices, while the term “network device” refers to a physical device that is accessed but not necessarily operated by a user of the network and may include, a scanner, server, switch, patch panel and the like. The network preferably includes a scanner102, which is used to monitor the network devices that are connected to the network104and which are connected via a series of patch panels106.

The scanners102monitor the network devices which are connected to the network. In one embodiment, the scanner102communicates with the patch panels106using a serial data connection. Each patch panel106is further connected to multiple network devices or the work area outlets107by way of a switch109. By connecting ports between the patch panels106with a patch cord, various network devices can communicate with each other. Switches109can probe all of the work area outlets on the network in order to catalog end-user devices connected thereto and in doing so, perform an inventory of all such devices connected to the network. A server105is connected to the switch109which is connected to the patch panels106and it may instruct the switches109to probe the connection ports of the patch panels106.

The patch panel106may be mounted in a rack with other such panels within a dedicated wiring room, such as a wiring closet. These panels106have a plurality of individual ports into which cables may be mated to connect the parts on various panels together. The rear of each port has a cable terminated to it, which leads to a work area outlet107to which an end-user device108may be connected. The cable may be of an Ethernet standard, containing eight conductive wires that are arranged as twisted pairs, i.e. four pairs of differential signal wires. The switches109, patch panels106, work area outlets107and end-user devices (collectively,108) cooperate to form the portion of the network104which the scanner102monitors.

FIG. 2is a diagram of one embodiment of a computing network including a patch panel, patch cords, network devices and end-user devices. Three patch panels112,114and116are shown arranged in a rack and are connected to network devices such as an ancillary server, or driver,118that is connected to the main server105of the network. The second patch panel114connects to another network device in the form of a public telephone system exchange (“PBX”)120, while a third patch panel112connects to the work area outlets and the various end-user devices, such as personal computers (“PCs”)122, a laptop computer124connected to a work area outlet located in a meeting room or similar environment, a VoIP (“Voice Over Internet Protocol”) phone126, a fax machine128and a printer130. One PC123connects to the third patch panel112through a modem132. In this exemplary embodiment, all of these devices cooperatively communicate using the IEEE 802.3 standard, commonly referred to as the Ethernet standard.

The VoIP phone126must connect to the PBX120in order to make and receive calls. Therefore, in this example, the VoIP phone126is wired to port1on the patch panel112. A patch cord134connects port1on the third patch panel112to port2on the second patch panel114. In this example, all ports on the second patch panel114are wired to the PBX120. Therefore, the VoIP phone126connects through the patch cord134to the PBX120. Likewise, the fax machine128and modem132connect to the PBX120through similar patch cords. The fax machine is wired to port5on the patch panel112and connects to the PBX120through patch cord136. Similarly, the modem132connects to the PBX through the patch cord138. The PCs122, laptop124and printer130are each wired to the patch panel112. Other patch cords140connect the respective ports for each device of the third patch panel112to the first patch panel116. Thus each of the PCs122, laptop124and printer130can communicate with the server118. In one embodiment, a switch (not shown) allows each of the end-user and network devices to communicate with each other.

In one embodiment, the system has the ability to perform the monitoring of all the devices connected to the network. For example, the master server105may monitor the issuance of addresses, such as dynamic host configuration protocol (“DHCP”) and internet protocol (IP) addresses. In some network environments, network devices obtain an IP address from a DHCP server when they connect to the network. In such an environment, the server105can monitor the issuance of IP addresses and poll newly connected devices using, for example, the simple network management protocol (“SNMP”). SNMP is used to monitor network attached devices.

U.S. Pat. No. 6,590,374, issued to Har-Lev describes one implementation for a terminator unit for use in networks for naming work area outlets and for verifying the normality of the wiring. The terminator unit of the '374 patent requires a pair of resistors be provided for each wire of a network work area outlet, and these resistor pairs are arranged so as to define a unique identifier code to the work area outlet for system monitoring purposes. As such, the structure of such a terminator unit is complex and requires extensive labor to compile the assignment of identifier codes by arranging the resistors in order to develop a binary code number to be used as the identifier. As such, the use of such a structure is complicated and requires a large amount of labor to install. The present invention provides an advantage over the terminator unit of the '374 patent, which is less expensive and does not require excessive labor for its implementation.

In the systems of the invention, an improved termination system such as that illustrated inFIGS. 3-4is used to enable the system to monitor the network at the work area outlet level and determine connectivity of the network cable to the work area outlet and other components of the network, as well as the connectivity of network devices to the work area outlets.FIGS. 3-4illustrate an RJ-45-style jack142including a termination unit144, which is used for connecting various network components together, including network devices to work area outlets. The jack142is used to provide a work area outlet at a specific location where a device may be installed by a connection thereto on an intended permanent basis or a transitory basis, such as in a meeting room, office or cubicle.

The jack142has a housing142athat is typically located within a wall plate in an office or room, and multiple work area outlets using multiple jacks may be located in a single room or office. The jack includes an internal socket145for accepting a device cable and the RJ-45 jack can accept any plug that is intermateable with an Ethernet outlet, meaning it has eight terminals arranged to provide four differential signal pairs. Other multi-paired wire jacks, such as RJ-11 jacks may be used. Individual terminals146in the jack mate with corresponding terminals in the network cable (not shown). The jack142may also include a shutter148that closes the opening of the jack. InFIGS. 3A-3B, the shutter148may be biased by a spring149and rotatably mounted within the jack142such that inserting a plug into the jack142rotates, or pivots, the shutter148downwardly toward the rear of the bottom of the jack opening145. When the plug is removed from the jack142, the shutter148springs into place at the front of the jack opening145. In this manner, the shutter148prevents dirt from entering the jack142and provides a means of determining whether the plug is fully inserted in to the jack142. If the plug is not fully inserted, the spring-loaded shutter148will eject the plug. As noted below, the shutter may be utilized to provide a parallel sensing circuit.

The termination unit144, as shown in the Drawings, takes the form of a cap that is generally U-shaped and includes a center slot150through which the network cable passes. The termination cap144preferably holds the cable to reduce stress on the connection between the cable and the network jack142. The network cable156connects to the jack142using insulation displacement technology (“IDT”) terminals152that are supported on a rear, terminating face149of the jack. The IDT terminals152pierce the insulation of the individual wires within the network cable in order to make an electrical connection between the jack terminals142and the network cable wires. Ribs154are disposed on the termination unit144that provide a means for the termination unit144to mate and engage the jack142. These ribs154are interconnected by cross pieces158that are received, at least partly, within slots162that are formed in the jack receptacle termination face160and which also house the IDC terminals. The termination unit144has a general U- or C-shaped configuration with a center slot150disposed therein.

FIG. 4illustrates a rear perspective of the work area outlet jack142including a network work area outlet cable156terminated to the jack and with a termination cap144in place, attached to the jack142. An electronic element is disposed within the termination cap144and it is preferably provided with leads so as to define a sensing circuit that makes contact with two of the wires in the network cable by way of the IDT terminals of the jack. This sensing circuit is disposed so that when the termination cap144is mated to the jack termination face, the sensing element becomes connected and a parallel circuit path is formed with wires of the network cable156. In terms of a specific sensing element, such as a resistor, the sensing resistor is connected by way of the termination cap144and now a parallel resistance, which is different than the resistance of open, unconnected outlet or a network device connected to the outlet can be read. The electronic sensing element may be a resistor, a capacitor, an inductor or pairs of any two or a combination of all three elements. All three elements will affect the system impedance at that location, as measured through the cable156and the sensing element in the termination cap144.

In the embodiment ofFIGS. 3A-3D, a resistor170is shown used as an electronic element with a measureable value to connect two terminals of the jack142together. The resistor170(FIGS. 3C-3D) may be mounted within the jack as opposed to the termination cap144, and specifically on the shutter148in a location such that when the shutter is in the closed position, the resistors make no contact with the terminals146in the jack142and the resistance measured by the system is that of an open (i.e., one to which no end-user device is connected) work area outlet, which provides a resistance value of infinity which indicates that no device is connected to the work area outlet. When an end-user device is connected to the work area outlet, the plug thereof is inserted into the jack142, as shown inFIG. 3D, the shutter148moves to the open position, and as the shutter slides back into the jack142, the resistor170is moved into contact with selected terminals146of the jack142, creating a new resistance value that can be sensed. This is shown diagrammatically inFIGS. 3C-3D, where the shutter148has a sliding movement as opposed to the rotating movement shown inFIGS. 3A-3B. As shown, the shutter moves between first and second operative positions where when the shutter is closed, the sensing circuit is not connected in parallel to the work area outlet and its associated network cable.

Alternate embodiments are contemplated, one of which is where one or more sensing elements, preferably resistors are mounted on the shutter148in a fashion such that when the shutter148is closed, the resistor(s) is connected to the work area outlet terminals and/or the network cable wires. When a connecting cable is inserted into the jack opening145, the shutter is displaced into an open position and the resistor(s) is moved out of contact with the terminals/wires, reducing the sensed resistance load on the work area outlet107. Different values may be measured by the system in this manner to indicate the status of the work area outlet107.

Therefore, in the particular embodiment ofFIGS. 3A-3D, a different resistive load is placed on the sensing circuit within the network cable when an end-user device is inserted into the jack142. Electronics to perform the sensing may be integrated into the patch panels106, scanner102, server105or into another dedicated or multifunction network device connected to the network104.

Another embodiment of a termination unit connected in accordance with the principles of the present invention is illustrated inFIGS. 5-16, wherein a work area outlet200is shown as including a jack-style housing202that is mounted to a circuit board204. The housing202is insulative and has a jack opening with a structure that is typical of Ethernet jacks. The inner terminals146of the jack opening include a plurality of tail portions206, typically eight in number to match the eight wires used in the arrangement of four pairs of differential signal wires commonly used in Ethernet data transfer. The tail portions206extend through holes, or vias208disposed in the circuit board204.

The tail portions206are connected to terminals210supported by a termination element211that has a termination face212disposed thereon. This termination face212is seen to include a flat base portion214and a plurality of posts216projecting out from the base portion214. The posts are arranged in two rows of five posts each and are spaced apart from each other to define an intervening space218therebetween. The posts216are themselves spaced apart from each other within each row and separated by intervening slots220that extend generally perpendicular to the intervening space218. Each slot220contains an IDT in the form of a conductive plate-like terminal221that has a center slot222defined therein between two opposing tine portions223. The slot222is sized so that the tine portions223bite into and pierce the outer insulation of the wires to make electrical contact between the wire and the terminal221. The network cable156may extend at least partially through the intervening space218and its individual wires spread out to engage the IDC of the termination face and the network cable may be extend straight out from the rear of the jack through the center slot247of the termination unit240.

In this regard, the termination unit240is provided in the form of a cap241that engages the termination face212of the jack termination element211. More specifically, the cap241is formed from an insulative material that has a preferably flat base portion242that has a well, or recess243disposed therein and defined by a plurality of sidewalls244. A pair of clips245may be found along two opposing edges of the base portion242as part of the sidewalls thereof. The recess243receives a circuit substrate246which, as illustrated inFIG. 12, is preferably planer and the substrate246and the base portion242include a central slot247. Visual indicia, in the form of a label, or decal248may be provided on the exposed surface of the substrate246in order to assist the installer. As with the first embodiment of the invention, this embodiment also includes a center slot247.

As shown best inFIG. 14, the base portion242further includes a means for engaging the work area outlet termination face212. This engagement means250is shown as two arrays, or rows251a,251bof projecting members252, disposed on opposite sides of the central slot. Each such array, or row includes a pair of spaced-apart sidewalls253a,253bthat have a series of interconnecting walls254which extend transversely to the sidewalls253a,253bin a spacing that matches that of the slots220located between the posts216of the termination face212.

Each interconnecting wall254includes a central notch255disposed therein. These notches255, as well as the interconnection walls254, are aligned with the IDCs of the work area outlet termination face212so that the intervening walls254do not have significant contact with the IDCs that would tend to spread them apart and compromise the integrity of their connection with the cable wires. Two of the notches255a,255bare deeper than the other notches255and a pair of conductive terminals260are supported by the base portion242in this location so that they project outwardly from the base portion242. These terminals260are shown in the Figures as pogo-pin style terminals and are received within corresponding bores261they have a length (or height) large enough so that they extend past, i.e. (above) the bottom wall262of the notches255.

In this manner, contact in assured between the two terminals260(at their tips) and the IDT. Pogo-pin style terminals are desirable in that they have a cylindrical body portion280with a spring loaded tip281held within a bore of the body portion. The internal spring283(shown inFIGS. 12 to 16), urges the tips281outwardly but will yield and retract under external pressure. The spring keeps the tips in contact with the IDT tines portions223in the terminal slots222, but deflects so that the tips281do not excessively spread the tine portions223apart.

In this embodiment, the parallel sensing circuit is within the termination cap, rather than the work area outlet jack. The terminals260are connected to the substrate246and specifically to a circuit270or circuits containing at least one resistive element, such as a resistor271. In operation, the resistive element271is part of a resistance circuit270that extends between the wires of two distinct differential signal pairs. An Ethernet standard cable has four differential signal pairs of wires, or eight wires total. In the present invention, the terminals260are arranged to form a circuit that extends between two of the signal wire pairs, connecting to one wire of a first differential pair to one wire of a second differential pair, rather than between wires that make up a pair. One usable resistance value is 1M (million) ohm that may connect to wires Nos. 2 and 7 of the four differential signal wire pairs. This is illustrated schematically inFIG. 17A, where a network cable156containing four pairs of wires dedicated to differential signal transmission are contained. The wires are shown grouped together as adjacent pairs1-2,4-5,3-6and7-8. The termination unit resistance circuit is connected across two distinct differential signal wire pairs, shown as the two end pairs inFIG. 17Aand specifically between wires2and7thereof. These two wires were chosen because they are aligned adjacent to each other on the terminating face of the work area outlet.

This connection creates the basis for a sensing circuit, described in this particular instance as the parallel resistance network structure shown inFIG. 17Balong the network cable that extends between a patch panel106and a work area outlet200. With the termination unit240in place upon a work area outlet, a sensing value equal to the constant resistance of 1M ohm is present via the sensing (resistance) circuit270of the termination unit240. This value indicates to a scanner of the system that a termination unit240is connected to the work area outlet200, and that there is neither a short circuit in the cable156terminated to the work area outlet200nor is there an end-user device, such as a PC122, connected to the work area outlet200. When an end-user is connected to the work area outlet200, the network device122now forms a second sensing circuit that is parallel to the sensing circuit (namely, the resistance circuit270) of the termination unit240, and that is connected in parallel across the differential pairs. Electrical signals will take the path of the lowest resistance and hence pass through the end-user device122giving a resistance reading to the scanner of the work area outlet of about 150 ohms. This change in resistance immediately indicates to the scanner that an end-user device has been plugged into a work area outlet200of the network100. Conversely, when the end-user device122is removed from a work area outlet200, the resistance read at the work area outlet200by the scanner immediately rises to a fixed value (1 M ohms), which is different (greater) than 150 ohms and (less) than the resistance of an open circuit, namely, infinity. In this manner, the three conditions of a work area outlet200may be read: about 150 ohms: end-user device connected, about 1M ohms: termination unit240in place but no end-user device present; and infinity ohms: no termination unit or end-user device present. Other resistance values are contemplated to be sensed for other conditions, such as a shorting of a break in the network cable156to that particular work area outlet108.

The termination unit240provides a sensing circuit that can be integrated into the work area outlet200such that the simple act of connecting or disconnecting an end-user device to the network work area outlet200forces a change in the impedance of the system that can be immediately measured. The termination units240may be easily installed at each existing work area outlet200of a network or new work area outlets when they are installed in a network. Their structure permits immediate connection to the network and the parallel resistance network that the unit240provides is a means by which the system connectivity may be monitored without relying upon numerous resistors or identifying codes. Accordingly, the network connectivity may be monitored remotely by reading the resistance at any given work area outlet to determine if an end-user device is or is not connected to the network at that particular work area outlet.

Capacitors may be used in place of the resistors described above and it will be appreciated that the manner in which they are used will effect a change in the status of the work area outlet that can be quickly detected by the scanner by way of a change in the impedance of the system connecting to that work area outlet. Likewise, inductors or any combination of elements that provide a change in the impedance of the system will also suffice. Termination caps may also be used at other connection points of the network in order to monitor the integrity and connectivity of the entire network. For example, a termination cap with a sensing element may be used at the connection of a network cable to a patch panel106, as well as at the scanner102, or even a switch109, in addition to the work area outlet107. The addition of these sensing elements to the sensing circuit will change the measureable system impedance which the scanner102can measure to determine connectivity and integrity of a particular cable or a particular cable connection. For example, the connection of two termination caps with sensing elements to the work area outlet107and the patch panel106will change the impedance of the system to a value different than the value obtained with only one termination cap with one sensing element attached to the work area outlet, as would the addition of a termination cap to a switch109. In such case the impedance of the network may be determined using the parallel and series circuit sensing values and measuring the same. As such, the termination caps provide a system designer with increased status information of the network, using the network components as connection, or end points, such as a break in the network cable between a switch109and a patch panel106or a patch panel106and the work area outlet107.

Still further as illustrated inFIG. 18, an electronic element, such as a resistor, capacitor, inductor or the like may be connected to one of the work area outlet terminals, and the element may have an electronic serial number associated therewith which can be read by the scanner as well as its particular value for identifying the work area outlet and the network device.