Protected Telephone Network Termination Module

This invention concerns telephone network interface devices. Such devices are shown in the following U.S. Pat. Nos.: 4,488,008; 4,560,839; 4,588,238; 4,624,514; 4,647,725; 4,723,919; 4,741,032; 4,742,541, 4,749,359; 4,800,588; 4,825,466; 4,945,559; 4,979,209. Such devices provide demarcation between the telephone company lines and the telephone subscriber's wiring. Such devices are generally compartmentalized so that the subscriber does not have access to the telephone company's portion of the device. The subscriber has access to a jack, typically an RJ-11C jack, and to terminals to which the subscriber's wiring can be connected. Such jack and terminals are often contained in a network interface module.

This invention is particularly concerned with network interface modules of the type that can be stacked in a side-by-side arrangement in, say, a substantially rectangular telephone network interface enclosure capable of handling a multiplicity of telephone lines. Examples of such enclosures are shown in U.S. Pat. Nos. 4,749,359 and 5,153,910. Examples thereof also are Sylvania CP-761 and CP-765 Network Interface Devices and Keptel SNI-4600 Telephone Network Interface. In such enclosures, the network interface module is generally located in the telephone subscriber's compartment while a protector unit for the module is located separately in the telephone company's compartment.

In this invention the protector unit is incorporated within the network interface module, herein called network termination module. Such an arrangement provides substantial space savings, which permits almost doubling the number of modules within an enclosure.

This invention discloses a network interface module, herein called network termination module, comprising a base structure having a means for grounding. Mounted on the base structure is an intermediate structure which contains a telephone jack and also a pair of line terminals for connection to telephone company wiring. A terminal strip is mounted above the intermediate structure, the terminal strip containing subscriber terminals for connection to a subscriber's wiring. Mounted above the terminal strip is an openable cover. The openable cover, when closed, establishes electrical connection between the line terminals and the subscriber terminals, and when opened, breaks said electrical connection. The line terminals are electrically connected to the telephone jack. There is a protector element disposed in the base structure which is electrically connected to the means for grounding.

FIG. 1 is an exploded perspective view of one example of a network termination module in accordance with this invention. FIG. 1a shows the module with its cover closed. FIG. 1b shows the module with its cover open.

FIG. 2 is a perspective bottom view of the part of the module that contains the subscriber terminals and the cover.

FIG. 3 is a perspective bottom view of the part of the module that contains the line terminals and the telephone jack.

FIG. 4 and FIG. 5 are perspective views of a telephone network enclosure containing the module of FIG. 1. In Fig. 4, the telephone company compartment of the enclosure is exposed, while in FIG. 5 it is covered.

One example of a network termination module 40 in accordance with this invention, as shown in the drawings, comprises a base structure 1 having a means for grounding 2 at one end thereof. Disposed within compartment 3 of base structure 1 is a telephone electronic circuit 4, for example, a maintenance termination unit or a half-ringer. Disposed within compartment 5 of base structure 1 is a protector element 6. Protector element 6 can be a bidirectional voltage sensitive switch, for example, a Surgector made by RCA Corporation or a Sidactor made by Teccor Electronics, Inc., as disclosed in U.S. Pat. patent application Ser. No. 07/705,215, the disclosure of which is incorporated herein by reference. Disposed on base structure 1 is an intermediate structure 7 on which are disposed a telephone jack 8 and a pair of line terminals 9. Line terminals 9 are recessed below the top of snap-on cover 10 in order to prevent accidental contact therewith. Telephone company wiring can be connected to line terminals 9 through wire entry ports 11. Bottom extensions 12 of line terminals 9 are connected to terminals 13 of protector element 6. Wires 14 serve to connect line terminals 9 to telephone electronic circuit 4, and wires 15 serve to connect line terminals 9 to telephone jack 8. Subscriber terminals 16 and openable cover 17 are supported on terminal strip 18. Subscriber terminals 16 are electrically connected to telephone plug 19 by means of wires 20 and cable 21. When openable cover 17 is closed, telephone plug 19 is inserted into telephone jack 8 which establishes electrical connection between line terminals 9 and subscriber terminals 16. The electrical connection is broken when openable cover 17 is opened.

Grounding terminal 22 of protector element 6 is connected to means for grounding 2 in order to provide for the grounding of a voltage or current surge appearing at either line terminal 9. Protector element 6 is encased in protector assembly 50 to which means for grounding 2 is attached.

Intermediate structure 7 can be secured to base structure 1 by ultrasonic welding. Terminal strip 18 can be removably attached to intermediate structure 7 by means of hinge means 23 on intermediate structure 7, into which fits extension 24 of terminal strip 18, and by means of releasable snap latch 25 fitting into an indent in intermediate structure 7. The removability of terminal strip 18 permits replacement of telephone plug 19 and subscriber terminals 16, if necessary, without the need of replacing the entire module.

Means for grounding 2 can also be a means for mounting. Network termination module 40 can be mounted in a telephone network enclosure 26 as shown in FIGS. 4 and 5. In one example, grounding clip 27, comprising part of means for grounding 2 of network interface module 40, would clip onto lug 28 of grounding strip 29. The resilience of grounding clip 27 would aid in its securing onto lug 28. In such an arrangement, tab 30 on base structure 1 would be inserted into recessed depression 31 of enclosure 26 before forcing grounding clip 27 down onto grounding lug 28., Having tab 30 and means for grounding 2 at opposite ends of network termination module 40 provides for secure mounting of the module in enclosure 26.

Network termination module 40 may have a shroud 32 surrounding grounding clip 27 for protection thereof. Shroud 32 may fit into notches 33 of grounding strip 29 in order to aid in securing the network interface module in enclosure 26.

Cover 17 has a hook 34 and alignment tabs 35 thereon so that rotation of a padlock (not shown) is prevented when the padlock hasp is placed under hook 34 and over alignment tabs 35. The purpose of such a padlock is to prevent unauthorized access to subscriber terminals 16 and jack 8 by padlocking cover 17 closed.

Cover 17 is secured in the closed position by means of snap action latch 36. Cover 17 can be opened by pressing snap action latch 36 in the direction of arrow 37. Arrow 37 may have a textured writing surface so that a telephone subscriber's telephone number may be written thereon.

Cover 17 has test access holes 38 small enough to prevent finger contact but through which telephone company probes may be inserted to verify telephone service while cover 17 remains closed.

In other embodiments, the protector element may be one or more gas tubes or carbon blocks disposed in base structure 1.

Telephone network interface enclosure 26 contains a telephone subscriber compartment 39 and a telephone company compartment 41. Grounding strip 29 is located in telephone company compartment 41. The major part of module 40 is located in telephone subscriber compartment 39. However line terminals 9 as well as means for grounding 2 are located in telephone company compartment 41. When telephone company cover 42 is closed, as shown in FIG. 5, it covers and prevents access to grounding strip 29 and means for grounding 2, as well as to line terminals 9. Telephone company cover 42 provides the demarcation between telephone subscriber compartment 39 and telephone company compartment 41.

Telephone company cover 42 has a slot 43 therein into which, when cover 42 is closed, fits hook 34 on openable cover 17. Thus when telephone company cover 42 is closed, a padlock (not shown) in place in hook 34 prevents opening of openable cover 17.

Grounding strip 29 is connected to grounding bolt 44 which would be connected to earth ground upon installation of enclosure 26. Telephone company wiring and grounding would be through grommet 45. Subscriber wiring would be through grommet 46.

In one embodiment, grounding strip 29 would be orthogonally mounted on back wall 47 of enclosure 26 by fitting into two upright slots 48 and would be secured by a nut 49 threaded onto bolt 44.

Telephone company cover 42 and subscriber cover 43 are hinged at the same side of enclosure 26. Subscriber cover 43, when closed, covers all of enclosure 26 including cover 42.