Customer Bridge Module

1. Field of the Invention

The present invention relates to telephone network interface apparatus and to modular devices for interconnecting telephone company ("telco ") wiring and subscriber telephone wiring. In particular, the invention relates to a customer bridge module having a plug-actuated switchable socket for connecting the telephone company and subscriber wiring and for providing a point of demarcation between the telephone company and the subscriber wiring such that an operating telephone can be plugged into the socket to determine whether a fault exists in the telco equipment or the subscriber premises. In addition, the customer bridge module may contain overcurrent protection, a half-ringer, a maintenance termination unit or a radio frequency interference (RFI) filter or a combination thereof.

2. Discussion of Related Art

Telephone subscribers may purchase and install their own telephone equipment and related appliances. Those subscribers are responsible for the proper operation of their equipment and the telephone company is responsible for service only up to the juncture between the telco wiring and the subscriber wiring. Thus, it is desirable to provide a telephone network interface apparatus which allows connection and disconnection of subscriber wiring from telco wiring so that the subscriber can readily isolate problems to the telco or subscriber equipment.

Modular devices are now available for use in telephone network interface apparatus that permit connecting and disconnecting the subscriber and telco wiring. Typical in the art are the modular devices shown in U.S. Pat. No. 4,979,209 issued to Thomas J. Collins et al. on Dec. 18, 1990, U.S. Pat. No. 5,153,910 issued to N. Peter Mickelson et al. on Oct. 6, 1992, U.S. Pat. No. 5,291,553 issued to Thomas J. Smith on Mar. 1, 1994, U.S. Pat. No. 5,297,199 issued to Thomas G. Graham et al. on Mar. 22, 1994 and U.S. Pat. No. 5,450,469 issued to Oliver Pamart et al on Sep. 12, 1995. There remains, however, a need in the art for easily installable modular devices having low cost and maintenance and increased functionality and reliability.

The Pamart et al patent discloses a socket with a switch which receives a special test plug to disconnect the telephone company and subscriber wires. The Collins et al., Mickelson et al. and Graham et al. patents disclose modular devices having an RJ-11 plug connected to the subscriber wiring and an RJ-11 socket connected to the telco wiring to form a series electrical connection between the telco and subscriber wiring. When the plug is removed from the socket, the subscriber wires are disconnected from the telco wires and the subscriber may plug an operating telephone into the socket to determine whether a fault exists with the telco or subscriber equipment. The Mickelson et al. patent discloses a protective element and a test circuit as permanent parts of the modular device. The Collins et al. and Graham et al. patents disclose an internal space in the modular device for a telephone circuit. The Collins et al. patent further discloses overvoltage protection devices separate from the modular devices. The Collins et al., Mickelson et al. and Graham et al. patents disclose connecting the subscriber wires and the telco wires using screws and/or nuts.

The Smith patent discloses a modular device with a special, normally conducting RJ-11 socket to connect the telco and subscriber wiring. This special socket is also disclosed in U.S. Pat. No. 5,030,123 issued to C. Kevin Silver on Jul. 9, 1991. When a telephone is plugged into the socket, the subscriber lines are disconnected from the telco lines and the telephone is connected to the telco lines through the contacts in the socket. As an alternative embodiment, the Smith patent discloses a conventional RJ-11 socket and a conductive cap member to complete the circuit between the telco and subscriber wiring. When the cap member is removed from the socket, the subscriber wires are disconnected from the telco wires and a telephone can be plugged into the socket to determine the location of the fault. The Smith patent further discloses an overvoltage protection device and a specific terminating impedance for the telco wires as a permanent part of the modular device. Finally, the Smith patent discloses connecting the subscriber wires to terminals using screws and connecting the telco wires to terminals using nuts.

The prior art also discloses that telco and subscriber wires may be terminated using insulation displacement contacts. U.S. Pat. No. 5,153,911 issued to Thomas J. Smith on Oct. 6, 1992 discloses a weatherproof telephone terminal apparatus which employs a bolt which is turned to drive two mating parts together to force wires into slots in the insulation displacement contacts. U.S. Pat. No. 4,988,311 issued to Charles Tanzola on Jan. 9, 1991 shows a similar termination method. U.S. Pat. No. 5,273,449 issued to John S. Mattis et al. on Dec. 28, 1993 shows a method for attaching telephone "drop wires" to a plug in which wires are inserted into the plug and a cover is snapped shut, driving the wires into slots in the insulation displacement contacts. The Mattis et al. patent also discloses using a reenterable gel material in connection with the insulation displacement contacts. The Pamart et al patent discloses lever actuated wire termination devices which employ insulation displacement contacts.

U.S. Pat. No. 5,235,638 issued to Paul C. Dondero on Aug. 10, 1993 discloses a telephone network interface apparatus having separate telco and subscriber compartments. The subscriber compartment contains sets of modular devices while the telco compartment has sockets for receiving plug-in overvoltage protection modules and plug-in electronics modules which form side-by-side protector and electronics fields. U.S. Pat. No. 5,025,345 issued to Robert J. Marks on Jun. 18, 1991 discloses an overvoltage protection module with an integral 5-pin plug for use in a protection field. U.S. Pat. No. 5,175,662 issued to George A. DeBalko et al. on Dec. 29, 1992 discloses a module with an integral 5-pin plug which includes both overvoltage protection and a maintenance termination unit. U.S. Pat. No. 5,260,994 issued to Lou Suffi on Nov. 9, 1993 discloses a modular maintenance termination unit with a 5-pin plug which contains, as part of the module, a telephone socket and a telephone plug.

Finally, U.S. Pat. No. 1,303,383 issued to Ralph W. Osborne on May 13, 1919 and U.S. Pat. No. 4,433,212 issued to Donald W. Moses et al. on Feb. 21, 1984 disclose the use of inductances in series with telco lines.

The present invention overcomes many of the disadvantages of the prior art network interface devices as exemplified by the various patents already discussed.

In prior art customer bridge modules, the telephone company and subscriber wires were connected together through the contacts in RJ-11 plugs and sockets. The contacts in RJ-11 plugs and sockets are relatively small gauge, typically 24 AWG or 25 AWG. Such small gauge contacts have limited current carrying capacity. The present invention eliminates the use of such small gauge contacts from the series connection between the telephone company and subscriber wires, thereby increasing the reliability of the network interface device. The present invention does so by connecting the telephone company and subscriber wires through a plug-actuated switch located on the customer bridge module. The switch contacts which connect the telephone company and subscriber wires are at least about 20 AWG and preferably at least about 18 AWG equivalent, i.e., they have the current carrying capacity of a 20 AWG or 18 AWG wire made of the same material. The contacts which mate with the plug are only connected to the telephone company lines when the plug is inserted in the socket and, therefore, may be smaller gauge such as 24 AWG or 25 AWG. Thus, while the present invention increases the reliability of the customer bridge module, it still provides a point of demarcation between the telephone company and subscriber equipment so that a subscriber can determine whether a fault exists in the telephone company or subscriber equipment.

The customer bridge module of the present invention may contain one or more electrical circuits connected between the telephone company lines and the plug actuated switchable socket. These circuits may include overcurrent protection, a half-ringer, a maintenance termination unit and an RFI filter. Combinations of these circuits can also be incorporated into the customer bridge module.

The foregoing and other advantages of the present invention will become apparent from the following description of the preferred embodiment which are intended to illustrate but not limit the invention.

FIG. 1 is a top view of a telephone network interface apparatus with the subscriber cover in a closed position.

FIG. 2 is a top view of the telephone network interface apparatus of FIG. 1 with the subscriber cover in an open position such that the subscriber compartment and the subscriber portions of the modular devices are visible.

FIG. 3 is a side view of the telephone network interface apparatus of FIG. 1 with the subscriber cover in the open position such that the subscriber compartment and the subscriber portions of the modular devices are visible.

FIG. 4 is a top view of the telephone network interface apparatus of FIG. 1 with the subscriber and telco covers both in open positions such that the subscriber and telco compartments and the subscriber and telco portions of the modular devices are visible.

FIG. 5 is a side view of the telephone network interface apparatus with the subscriber and telco covers both in open positions such that the subscriber and telco compartments and the subscriber and telco portions of the modular devices are visible.

FIG. 6 is a side view of an embodiment of the modular device showing a replaceable protection/electronics unit.

FIG. 7 is a front view of an embodiment of the modular device.

FIG. 8 is a rear view of an embodiment of the modular device.

FIG. 9 is top view of an embodiment of the modular device.

FIG. 10 is a perspective view of an embodiment of the modular device.

FIG. 11 is a schematic diagram of the modular device and the replaceable protection/electronics unit.

FIG. 12 is a side view of an embodiment of the modular device in a partial cross-section.

FIG. 13 is another side view of an embodiment of the modular device in partial cross-section.

FIG. 14 is a cross-sectional view of the switchable RJ-11 type socket.

FIG. 15 is another cross-sectional view of the switchable RJ-11 type socket.

FIG. 16 is a cross-sectional view of the switchable RJ-11 type socket with an RJ-11 plug inserted therein.

FIG. 17 is a perspective view of one set of contacts in the switchable RJ-11 type socket showing the connection of the telco and customer contacts.

FIG. 18 is a perspective view of one set of contacts in the RJ-11 type switchable socket showing the connection of the telco and test contacts.

FIGS. 19 is a perspective view of a rocker arm wire termination mechanism.

FIG. 20 is a side view of the rocker arm termination mechanism showing the rocker arm termination mechanism in the open position.

FIG. 21 is a side view of the rocker arm termination mechanism showing the rocker arm termination mechanism in the closed position.

FIG. 22 is a front view of the rocker arm termination mechanism.

FIG. 23 is a front view of a portion of the modular device showing hardware for mounting the rocker arm termination mechanism.

FIG. 24 is a top view of a portion of the modular device showing hardware for mounting the rocker arm termination mechanism.

FIG. 25 is two perspective views of a cam actuated wire termination mechanism.

FIG. 26 is a side view of a lever for use in the cam actuated wire termination mechanism.

FIG. 27 is a front view of a main body portion for use in the cam actuated wire termination mechanism.

FIG. 28 is a cross-sectional view of the main body portion for use in the cam actuated wire termination mechanism.

FIG. 29 is a side view of a portion of the modular device showing mounting hardware for the cam actuated wire termination mechanism.

FIG. 30 is a front view of a portion of the modular device showing mounting hardware for a cam actuated wire termination mechanism.

FIGS. 31, 32, 33 and 34 are side views of the cam actuated wire termination mechanism.

FIG. 35 is a top view of an individual security cover for the modular device.

FIG. 36 is a side view of the individual security cover for the modular device.

FIG. 37 is a front view of the individual security cover for the modular device.

FIG. 38 is a top view of another embodiment of the telephone network interface apparatus with the subscriber cover in an open position such that the subscriber compartment and the subscriber portions of the modular devices are visible.

FIG. 39 is a top view of another embodiment of the telephone network interface apparatus with the subscriber and telco covers both in open positions such that the subscriber and telco compartments and the subscriber and telco portions of the modular devices are visible.

FIG. 40 is a side view of another embodiment of the telephone network interface apparatus with the subscriber and telco covers both in open positions such that the subscriber and telco compartments and the subscriber and telco portions of the modular devices are visible.

FIG. 41 is a perspective view of another embodiment of the modular device.

FIG. 42 is a perspective view of another embodiment of the modular device.

FIG. 43 is a partially exploded perspective view of a customer bridge module.

FIG. 44 is a schematic drawing of a customer bridge module with overcurrent protection.

FIG. 45 is a schematic drawing of a customer bridge module with overcurrent protection and a half-ringer.

FIG. 46 is a schematic drawing of a customer bridge module with overcurrent protection and a maintenance termination unit.

FIG. 47 is a schematic drawing of a customer bridge module with overcurrent protection and an RFI filter.

Referring to the figures, and in particular FIGS. 1-5, there is shown a telephone network interface apparatus 10. The telephone network interface apparatus 10 includes a subscriber cover 12, a telephone company cover 14, a base 16 and modular devices 18 and 20. The subscriber cover 12 and telco cover 14 are attached by hinges 22 to the base 16 of the telephone network interface apparatus 10.

The subscriber cover 12 is secured in a closed position by conventional fastener 24 as shown in FIG. 1. Upon removing fastener 24, the subscriber cover can be rotated to an open position. When the subscriber cover 12 is open, as shown in FIG. 2, the subscriber compartment and the subscriber portions of modular devices 18 and 20 are visible.

The telco cover 14 is secured in a closed position by fastener 26. When the subscriber cover 12 is in the open position, fastener 26 can be removed and the telco cover can be rotated to an open position. Fastener 26 is not easily removed by a subscriber because it requires a special tool. When the subscriber and telco covers are both in the open position, as shown in FIG. 4, the subscriber and telco compartments and the subscriber and telco portions of the modular devices 18 and 20 are visible.

As shown in FIGS. 1, 2 and 4, the telephone network interface apparatus 10 has openings 28 for subscriber and telco wiring. The openings 28 may be provided with grommets 30 and covered with downwardly extending protective cover members 32 for covering the subscriber and telco wiring. As would be understood by a person skilled in the art, the telephone network interface apparatus may be provided with other means for weatherproofing, for example, sealed electrical connections and/or gels. Also, the telephone network interface apparatus 10 has mounting brackets 34 formed integrally with the base 16.

The telephone network interface apparatus 10 includes removably mounted modular devices 18 and 20. Modular devices 18 may be used to connect telco and subscriber wiring in the form of coaxial cable or fiber optic cable while modular devices 20 may be used to connect conventional insulated telco and subscriber wiring. The modular devices 20 are commonly referred to as customer bridge modules or subscriber bridge modules.

When the telephone network interface apparatus is used to connect coaxial cable or fiber optic cable, it is highly desirable to employ bend radius control. A bend radius control guide 36 is shown molded into the base 16 of the telephone network interface apparatus 10 to ensure that the bend radius of the cable is not less than about 1.5 inches. Other types of bend radius control devices such as brackets or clamps could also be employed. As shown in FIG. 4, coaxial cable or fiber optic cable may be directly connected at the telephone network interface apparatus using a "bulkhead-type" connection 19 or may be connected through modular device 18.

The telephone network interface apparatus shown in FIGS. 1, 2 and 4 is designed to contain up to six modular devices. As would be understood by a person of ordinary skill in the art, the telephone network interface apparatus may be designed to contain more or less than the six modular devices shown.

The general structure of a modular device 20 for connecting conventional insulated telco and subscriber wiring may be understood by reference to FIGS. 3-10 and by particular reference to FIGS. 5, 6 and 10. Device 20 includes a housing 38, a replaceable protection and/or electronics unit 40, a pair of rocker arm termination mechanisms 42 and a cam actuated termination mechanism 44. The housing 38 is generally rectangular and includes an opening 46 for receiving the replaceable protection and/or electronics unit 40. The pair of rocker arm termination mechanisms 42 and the cam actuated termination mechanism 44 are mounted on opposite ends of modular device 20. Termination mechanism 44, protection/electronics unit 40, and termination mechanism 42 are electrically connected through an electrically conductive path. (not shown) within device 20.

As shown schematically in FIG. 11, the protection/ electronics unit 40 may include an overvoltage protection device in the form of a gas tube 48, a maintenance termination unit 50 and a ringer simulator (half ringer) 52. It may also include a transient protection in the form of series inductances 54 and 56. The inductances should be sufficiently large to limit transients while, at the same time, not so large as to seriously limit the bandwidth of the communication link. Therefore, the inductances may be in the range of 50 to 200 microhenries and preferably in the range of 50 to 150 microhenries and more preferably in the range of 50 to 100 microhenries. As would be understood by a person of ordinary skill in the art, the content of the removable unit 40 is not limited and can accommodate additional electronic components. The removable protection/electronics unit 40 has five electrical contacts, as shown schematically in FIG. 11 and as shown in part in FIGS. 5, 6, 12 and 13. Contacts 57 and 59 are connected to the telco wires 58 and 60, contacts 61 and 63 are connected to the subscriber wires 62 and 64 and contact 65 is connected to ground 66.

The removable protection/electronics unit may also have a plug-actuated switchable RJ-11 type socket 68 that may be connected to a test phone 69 as shown schematically in FIG. 11 and as shown in FIGS. 9 and 10. As shown in FIGS. 14-18, the plug actuated switchable RJ-11 type socket 68 has a customer contact 78 connected to the subscriber wires, a telco contact 80 connected to the telco wires and a test contact 82 for connection to a plug. The test contact 82 does not lie in the same plane as the customer and telco contacts 78 and 80.

FIGS. 17 and 18 show the interaction of the customer, telco and test contacts. As would be understood by a person of ordinary skill in the art, FIGS. 17 and 18 show one set of customer, telco and test contacts. However, the switchable RJ-11 type socket actually has two sets of such contacts to accommodate the pair of telco and subscriber wires.

When the RJ-11 plug is not plugged into the switchable RJ-11 type socket 68, the telco contact 80, and thus the telco wires, are connected to the customer contact 78, and thus the subscriber wires, and the test contact 82 is out of the circuit. When the RJ-11 plug is inserted in socket 68 the customer contact 78, and thus the subscriber wires, are disconnected from the telco contact 80, and thus the telco wires, and the telco contact and telco wires are connected to the test contact 82 in socket 68 which mate with contacts in the RJ-11 test plug. Although shown as part of the replaceable protection/electronics module, the switchable RJ-11 type socket 68 could also be part of the module housing 38.

As shown schematically in FIG. 11, the module housing 38 has a pair of test points 70 and 72 connected to the telco wires and a pair of test points 74 and 76 connected to the subscriber wires.

Modular devices 20 as shown in FIGS. 3-5, 6 and 10 represent one embodiment of the invention. Devices 20 have one pair of rocker arm wire termination mechanisms 42 and a replaceable protection/electronics unit 40. As would be understood by a person of ordinary skill in the art, the modular device 20 could have two pairs of rocker arm wire termination mechanisms 42 and a replaceable protection/electronics unit 40 because some telephone companies use four wire arrangements. Two pair of rocker arm wire terminations 42 would permit connecting four pairs of subscriber wires to the modular device 20.

Referring now to FIGS. 12, 13 and 19-24, there is disclosed details of the rocker arm wire termination mechanism 42. Each rocker arm includes two legs 82 and 84 and a pivot 86 between legs 82 and 84. The pair of rocker arm terminations 42 are mounted to housing 38 of device 20 at the pivot 86 such that one leg 84 of each rocker arm faces to the front of the device and the other leg 82 of each rocker arm faces to the rear of the device. Leg 84 has two openings, 88, and a cavity 90 which is generally perpendicular to and communicates with openings 88. Openings 88 are adapted to receive subscriber wires 92. As would be understood by a person of ordinary skill in the art, some subscriber premises are wired so that each phone has separate wires connected directly to the modular device. Two openings 88 are provided on each rocker 42 to permit connecting two subscriber wires in such situations. Cavity 90 in leg 84 is adapted to receive an insulation displacement contact 92 mounted on housing 38. The modular device 20 housing 38 has projections 96. The pair of rocker arm terminations 42 are mounted on the projections 96 by pivot point 86 such that when the rocker arm is pivoted about point 86 the cavity 90 in each rocker arm is forced down over insulation displacement contact 92 which is mounted on device 20. Each insulation displacement contact 92 has a slot which is adapted to receive an insulated wire. Contact 92 is connected to an electrical conductor 94 within housing 38. The electrical conductor 94 is also connected to a test point 102.

In use, the rocker arm terminations 42 connect subscriber lines 92 to device 20 using a minimal amount of force and without the need for tools. Rocker arm termination 42a is shown in FIGS. 19 and 20 in an open, disconnected position. A peg 98 extends from projection 96. Rocker arm termination 42 is held in an open position by the peg 98. When subscriber wire 92 is inserted into opening 88 and pressure is applied to leg 84, peg 98 is released, the rocker arm 42 rotates, subscriber wire 92 is driven into the slot in insulation displacement contact 92 and contact 92 is forced into cavity 90. Rocker arm termination 42b in FIGS. 19 and 21 is shown in a closed, connected position such that the subscriber line 92 is connected to the modular device 20. Peg 98 engages a notch 100 to hold rocker arm termination 42 in the closed position. In this position, a telco employee can test the circuit without disturbing the subscriber line connection by touching test point 102 with an electrical test probe.

Referring now to FIGS. 12, 13 and 25-34, there is disclosed a cam actuated wire termination mechanism 44 which includes a lever 104, a pivot point 106, and a main body 108. The housing 38 is provided with projections 110. Lever 104 is mounted to housing 38 of device 20 at the projection 110 by pivot point 106. The lever 104 includes an arcurate-shaped slot 112 having two ends 114 and 116. The distance from slot 112 to pivot point 106 is less at the first end 114 of slot 112 than at the second end 116 of slot 112. The main body 108 of termination mechanism 44 includes a pin 118 which fits in slot 112 of lever 104. Rotating lever 104 causes main body 108 to translate up and down in a vertical direction.

The main body 108 also includes openings 120 and 122 and cavities 124 and 126 which are perpendicular to and communicate with openings 120 and 122. Openings 120 and 122 are adapted to receive wires 128 of different sizes. As would be understood by a person of ordinary skill in the art, telephone companies have traditionally used larger gauge wire but more recently have begun to use smaller gauge wire. Openings 120 and 122 are designed to accommodate both sizes of telco wiring. Cavities 124 and 126 are adapted to receive an insulation displacement contacts 128 and 130 which are mounted on housing 38 of device 20. When lever 104 is rotated counterclockwise, the main body 108 is driven downward and insulation displacement contacts 128 and 130 are driven into cavities 124 and 126 respectively.

In use, the cam actuated wire termination mechanism 44 connects telco wires to modular device 20 using a minimal amount of force and without the need for tools. As shown in FIGS. 25 and 31-34, termination mechanism 44a is in an open, disconnected position. Telco wires 128 are inserted into openings 120 and pressure is applied to lever 104 in the direction of force F. The force on lever 104 causes the lever 104 to rotate about the pivot point 106 which in turn causes pin 118 to ride in slot 112 from position 114 to position 116. Because the distance between the pivot point 106 and the slot 112 is less at the first end of the slot 114 than at the second end of the slot 116, the force causes the main body 108 downward and forces wires 128 into slots in insulation displacement contact 128. Termination mechanism 44b is in the closed, connected position such that the telco lines 128 are connected to the modular device 20.

The projection 110 upon which the cam actuated wire termination mechanism is mounted to modular device housing 33 is provided with a peg 132. In the closed position, peg 132 engages knob 135 to secure the lever 104. Test point 134 is provided so that the telco wire may be contacted by a test probe even when the cam actuated wire termination mechanism is in the closed position.

As shown in FIG. 5, modular device 20 is mounted to base 16 of the telephone network interface apparatus 10. Device 20 has a projection 140 (FIG. 12 and 13) that engages a corresponding notch on the base 16 to secure modular device 20 to the base 16. Base 16 has a buss 136 that runs the length of the telephone network interface apparatus 10 and that electrically connects ground terminal 66 on the replaceable protection/electronics units 40 of the devices 20 with a bolt 138 that is grounded.

To address environmental concerns, the removable protection/electronics units contacts 57, 59, 61, 63 and 65, the test points 70, 72, 74 and 76, the insulation displacement contacts 92, 128 and 120, the buss 136 may be encased in gels of the type disclosed in U.S. Pat. No. 5,273,449 issued to Raychem Corporation. In addition, the insulation displacement contacts 92, 128 and 130 of the rocker arm and cam activated terminations 42 and 44 are mounted to the housing 38 of the modular device 20 at pedestals 136 and 138. Pedestals 136 and 138 prevent water that may get through the gel from seeping into the housing 38.

As shown in FIG. 2, when the subscriber cover is open, subscribers can access the subscriber portion of the modular device 20. However, subscribers may choose to protect their telephone lines from persons seeking illicit access. The subscriber portion of the modular devices 20 are covered by individual subscriber security covers 142 which are secured by padlocks. Security covers 142 limit access to the subscriber portion of devices 20. When the padlock is removed as shown in FIGS. 3, 5, 6 and 10, the individual subscriber security covers hinge open at hinge 143 and the rocker arm terminations 42 are readily accessible.

Alternately, the security cover 142 can slide to expose the subscriber portion of the modular device 20. As shown in FIGS. 35-37, the telco cover can be provided with channels 144 and the security cover 142 with projections 146 that ride in channels 144 such that the security cover can slide back an d forth. Alternatively, as can be understood by reference to FIGS. 40-42, the individual security cover can wrap around the modular device and can be provided with projections that slid e in channels in the modular device (not shown). As shown in FIGS. 31, 32 and 34, when the telco cover 14 is closed, security covers 142 and the padlocks rest against the edge of the telco cover 14 and cannot slide. When the padlock is removed, the individual security 142 can slide in channels 144 to expose the subscriber portions of modular device 20. The cover 142 does not, however, slide so far as to give the subscriber access to the replaceable unit 40.

The individual subscriber security covers 142 do not prevent the telephone company from accessing the subscriber portions of devices 20. As can be understood from FIGS. 4 and 5, when the telco cover is open, the padlock no longer abuts the telco cover and can be removed so that the individual security cover 142 can b e hinged open. In the case of the sliding individual security covers 142 that ride in channels on the telco cover, the sliding individual security cover will open with the telco cover because the individual security cover stays in channels 144 when the telco cover is opened as can be understood from FIGS. 36 and 37. In the case of the sliding individual security covers 142 that ride in channels on the modular device, when the telco cover is open, the security cover no longer abuts the telco cover and can slide open as shown in FIG. 39.

An alternative embodiment of the modular device 20, may be understood by reference to FIGS. 38-42. Device 20 includes a switch 148 that electrically connects the telco wiring to a RJ-11 type socket 166 mounted on the base 16 of the telephone network interface apparatus 10.

Modular device 20a as shown in FIG. 40 represent one embodiment of this alternative embodiment of the invention. Device 20a have one pair of rocker arm wire termination mechanisms 42 and a replaceable protection/electronics unit 40. Modular device 20b as shown in FIG. 41 represents another embodiment of the alternative embodiment of the invention. Device 20b has two pairs of rocker arm wire termination mechanisms 42 and a replaceable protection/electronics unit 40. The two pair of rocker arm wire terminations 27 permit connecting four pairs of subscriber wires to device 20b. Modular device 20c as shown in FIG. 42 represents still another embodiment of the invention. Device 20c has two pairs of rocker arm terminations 42 and built-in protection and/or electronics (not shown). As would be understood by a person of ordinary skill in the art, another alternative embodiment of the invention could have one pair of rocker arm terminations 42 and built-in protection and/or electronics.

As shown in FIGS. 40-42, modular devices 20 are mounted to base 16 of the telephone network interface apparatus 10. Base 16 has busses 150, 152 and 154 and an upwardly extending inverted L-shaped member 156. Device 20 has notches 150, 160 and 162 having electrical contacts (not shown) to receive and make an electrical connection with the busses 150, 152, 154. Device 20 also has a notch 164 which receives the L-shaped member 156. The device 20 is secured to the base 16 by the interaction of the busses 150, 152 and 154 and the buss receiving notches 158, 160, 162, as well as the L-shaped projection 156 and notch 164.

The busses 150, 152 and 154 on base 16 run the length of the telephone network interface apparatus 10 and connect with a conventional RJ-11 telephone socket 166. Rocker arm termination 42, replaceable protection/electronics unit 40, switch 148 and cam actuated termination 44 are all electrically connected through an electrically conductive path (not shown) within housing 38 of device 20. Switch 148 is also electrically connected to busses 150, 152, 154. Switch 148 creates a point of demarcation between the subscriber wiring and the telco wiring by disconnecting the subscriber lines from the telco lines and by connecting the telco lines to the busses 150, 152 and 154, which are in turn connected to the socket 166. Thus, the subscriber may test his line by plugging his telephone into socket 166 and actuating switch 148 (which may be a "push-to-test" type switch) and determine if problems exist in his line or in the telco equipment.

FIG. 43 shows a customer bridge module 200 comprising a housing 202 and a printed circuit board 204 on which a variety of electrical components may be mounted. The printed circuit board is designed to be mounted within the housing. Connected to the printed circuit board are wires 206 and 208 which are adapted to be connected to the telephone company wires. Located on housing 202 are terminals 210 and 212 which are adapted to be connected to the subscriber wires. Also located on housing 202 is plugactuated switchable socket 214 which is preferably designed to receive a conventional RJ-11 or RJ-45 plug.

FIG. 44 shows a schematic diagram of a customer bridge module with overcurrent protection. The left hand side of the circuit is adapted to be connected to the telephone company wires and the right hand side of the circuit is designed to be connected to the subscriber wires. The overcurrent protection portion of the circuit comprises positive temperature coefficient resistors (PTCRs) 220 and 222 and inductors 224 and 226 connected in series with the respective PTCRs. The inductors limit the current flow caused by high frequency transients (spikes) with fast rise times. The PTCRs limit current flow caused by lower frequency signals. As the current flows through the PTCR, the resistance increases and the current flow is reduced.

The second part of the circuit in FIG. 44 involves the operation of plug-actuated switchable socket 214. The socket contains a pair of telco contacts, a pair of subscriber contacts and a pair of test contacts. As noted above, the telco and subscriber contacts are of a heavier gauge wire than the test contacts and, therefore, have a greater current carrying capacity than the test contacts. The telco contacts are connected to inductors 224 and 226, while the subscriber contacts are connected to terminals 210 and 212. In the absence of a plug in socket 214, the telco and subscriber contacts are connected. To test the phone lines a telephone having a plug 230 is plugged into socket 214. This disconnects the telco contacts from the subscriber contacts and connects the telco contacts to the test contacts in socket 214. The operation of plug-actuated switchable socket 214 is the same in FIGS. 45 through 47.

FIG. 45 is a schematic diagram of a customer bridge module with overcurrent protection and a conventional half-ringer (ringer simulation) circuit 232. The overcurrent protection is provided by PTCRs 220 and 222 and inductors 224 and 226. The half-ringer circuit is connected across the input of the overcurrent protection circuit.

FIG. 46 is a schematic diagram of a customer bridge module with overcurrent protection and a conventional maintenance termination unit 234. The overcurrent protection is provided by PTCRs 220 and 222 and inductors 224 and 226. The maintenance termination unit is connected across the input of the overcurrent protection circuit and is interrogated from the telephone company central office. Both switches in the maintenance termination unit open and close together under the control of the central office.

FIG. 47 is a schematic diagram of a customer bridge module with overcurrent protection and an RFI filter. The overcurrent protection is provided by PTCRs 220 and 222 and inductors 224a, 224b, 224c, 226a, 226b and 226c. The RFI filter is provided by inductors 224a, 224b, 224c, 226a, 226b and 226c in combination with capacitors 236a, 236b and 236c. The inductors and capacitors form a multi-pole low pass filter.

While the present invention has been described by reference to various preferred embodiments, it will be understood by persons skilled in the art that many modifications and variations may be made in those preferred embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that the invention not be limited to the disclosed preferred embodiments, but that it have the full scope permitted by the following claims.