Telephone wiring interconnect apparatus and method

Details Telephone wiring interconnect apparatus and method Telephone wiring interconnect apparatus and method

2001-02-02

2003-04-01

Field, Lynn (Department: 2839)

Electrical connectors

Having circuit interrupting provision effected by mating or...

Reexamination Certificate

active

06540534

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to telephone wiring interconnect apparatus and method, and more particularly, to an interconnect apparatus of the type commonly used in a network interface device (NID), such as a protected terminal device (PID) or line module. The apparatus is used to interconnect wiring from a telephone service provider with subscriber wiring. Specifically, the present invention relates to an improved telephone interconnect apparatus that can withstand overcurrent and overvoltage conditions.
2. Description of the Related Art
Telephone service is provided by a telephone company (“Telco”) to a number of different subscribers. Each subscriber may purchase as many separate telephone lines as desired and equip his or her home or business with various telephone equipment. Subscribers are responsible for proper operation of the telephone equipment and the Telco is responsible for proper operation of the telephone network up to the interface between the Telco wiring and the subscriber wiring. Therefore, it is desirable to provide a telephone network interface device (NID) to serve as demarcation point between the Telco wiring and the subscriber wiring.
FIG. 1
illustrates a typical prior art NID
10
. The NID
10
may be mounted to an exterior wall of a house or commercial building
2
. The Telco wiring
4
enters the NID and terminates in a locked inner enclosure
12
, which is shown in the open position for purposes of clarity. The Telco wiring
4
may come in bundle, of, for example, twisted pair wires. The bundle of twisted pair wires can-be split and each pair terminated into a connector block within the inner enclosure
12
.
The inner enclosure
12
is preferably locked to prevent unauthorized access by the subscriber or vandals. Typically, each subscriber telephone line is serviced by one set of twisted pair wires, commonly referred to as the “tip” and “ring” wires. Each of the twisted pair wires is electrically connected to an interconnect apparatus, such as a protected terminal device (PTD) or line module
100
, located adjacent the inner enclosure
12
. In other words, the tip and ring wires from one twisted pair are inserted into one end of the interconnect apparatus
100
and electrically coupled to a pair of conductors within the apparatus. The interconnect apparatus
100
is typically a modular device that can be mounted in the NID and easily replaced if rendered inoperable.
Referring to
FIGS. 2A
to
2
E, a prior art line module
100
is shown in greater detail. The line module
100
has a housing
102
and a cover
104
that can pivot between a closed position, as shown in
FIG. 2A
, and an open position, as shown in FIG.
2
B. The housing
102
of the line module
100
has a pair of insertion channels
124
that allow that Telco wires
4
to be electrically coupled with a pair of contacts
122
(
FIG. 2E
) located in an integrated jack
112
. As shown, the jack
122
is a conventional RJ-11 jack. The cover
104
may be connected to the line module
100
by a hinge
120
(
FIG. 2C
) so that the cover
104
can be rotated away from the housing
102
of the line module
100
to permit access to the jack
112
. As mentioned, the jack
112
has a pair of contacts
122
that are electrically coupled to the tip and ring wires. Likewise, plug
110
attached to the cover
104
has a complementary pair of conductors
114
that make contact with the jack contacts
122
when the plug
110
is engaged in the jack
112
. The subscriber wires
6
are connected to a pair of terminals
118
provided on a portion of the line module
100
known as the bridge
108
. The plug conductors
114
are also electrically coupled to the terminals
118
. Thus, when the cover
104
is closed, an electrical circuit is completed between the Telco wires
4
and the subscriber wires
6
. When the cover
104
is opened, the subscriber wires
6
are disconnected from the Telco wires
4
. However, a test plug (not shown) can be plugged into the jack
112
to determine if the Telco wires
4
up to the line module
100
are conducting properly. As shown in
FIGS. 2C and 2D
, the bridge
108
is removable, and thus, replaceable if rendered inoperable. However, line module
100
may also be provided with a non-removable bridge.
The spacing and size of the plug conductors
114
and the jack conductors
122
are sources of failure when the line module
100
is subjected to overvoltage and overcurrent conditions. For example, a lightning strike on a telephone line may cause a voltage spike that will result in an electric arc between the tip and ring contacts of either the jack or the plug. In other words, the tip and ring wires are at different voltages. An overvoltage event magnifies the difference and may cause an electrical arc to jump between the closely spaced contacts. The contacts in RJ-11 plugs and sockets are relatively small gauge, typically 24 AWG or 25 AWG. An overcurrent event may result in the plug and jack conductors in contact with each other welding together. In either event, the line module
100
is rendered inoperable.
U.S. Pat. No. 5,153,910 discloses an example of a protected terminal device (PTD) for a NID used to connect Telco wiring with subscriber wiring. When the cover of the PTD is closed, an actuator presses a set of conductors into contact with a complementary set of thin lead contacts. The lead contacts in turn are connected to the Telco wiring. The subscriber wiring is connected through two terminal screws to the set of conductors. Thus, an electrical signal path is created from the subscriber wiring, through the terminal screws and conductors, and into lead contacts. While this simple design allows for easy connection of the subscriber and Telco wiring, it does not address the causes of the arcing or welding failure modes. Specifically, arcing may occur between the lead contacts because they are closely spaced. Furthermore, the small gauge lead contacts may become welded to the conductors.
It is thus apparent a particular need exists for an improved interconnect apparatus that can withstand overcurrent conditions and overvoltage conditions.
It is further apparent that a particular need exists for an improved interconnect apparatus including a test plug that remains functional when a cover is removed from the bridge and the electrical circuit between the Telco wires and the subscriber wires is broken.
It is further apparent that a particular need exists for an improved interconnect apparatus that can withstand overvoltage and overcurrent conditions regardless of whether the bridge is fixed or removable.
BRIEF SUMMARY OF THE INVENTION
The present invention relates to an improved interconnect apparatus, such as a protected terminal device (PTD) or line module, that can withstand overcurrent and overvoltage event, such as a lightening strike. The interconnect apparatus may, for example, be mounted within a conventional network interface device (NID). The interconnect apparatus uses large gauge by-pass conductors for signal transmission from the Telco to the subscriber rather than small gauge contacts. However, the jack located in the housing of the interconnect apparatus retains standard sized contacts that will interface with conventional test plugs.
In one embodiment, the improved interconnect apparatus includes a housing having a removable bridge and cover assembly. The bridge includes terminals for connection to the subscriber wires. The housing includes a jack having a first set of by-pass conductors and a first set of contacts. The first set of by-pass conductors include one conductor for the tip wire and one conductor for the ring wire. The first set of by-pass conductors oppose a second set of by-pass conductors located on a plug. The plug can be attached to the cover. When the plug is engaged with the jack, the first set of by-pass conductors electrically couple with the second set of by-pass conductors to complete an electrical circuit between the Telco wires and the subscriber wires. The plug, however,

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