Telephonic communications – Subscriber line or transmission line interface – Network interface device
Reexamination Certificate
1997-10-06
2002-08-20
Isen, Forester W. (Department: 2654)
Telephonic communications
Subscriber line or transmission line interface
Network interface device
C379S093050, C370S327000
Reexamination Certificate
active
06438226
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a xDSL splitter block for mounting on a central office telecommunications main distribution frame with xDSL splitter circuits housed therein.
BACKGROUND OF THE INVENTION
ADSL (Asymmetric Digital Subscriber Line) is a modem technology that transmits multimedia and high speed data over existing twisted-pair telephones lines concurrently with Plain Old Telephone Service (POTS). VDSL is a higher speed variation of ADSL. The term xDSL will be used herein to generically refer to these different versions of transmitting additional signals over twisted pair concurrently with the POTS signal. The term “additional signals” will be used to refer to any signal other than POTS that is transmitted over the existing POTS lines. The term “combined signals” will be used to refer to both the additional signals and POTS signals combined over a line. An xDSL circuit connects an xDSL modem on each end of a twisted-pair telephone line, that is, at the “central office” (or node) and at the premises of the subscriber (or customer). The xDSL modem in the central office transmits and receives the additional signals through a “splitter” that combines the downstream (to the subscriber) additional signals onto the POTS fine or filters off the upstream (from the subscriber) POTS signals.
The terms “splitting” or “splitter” are used to refer to a circuit, for example, a low pass filter or low pass and high pass filter combination, that at least separates a POTS signal from a combined signal in the case of the example of a low pass filter and separates both the POTS and xDSL signals from the combined signal in the example of the low pass and high pass filter combination. In other words, the signal upstream from the splitter to the xDSL modem may or may not have the POTS signal filtered off since xDSL modems may incorporate high pass filters and may not be affected by or even see the POTS signals being transmitted with the xDSL signals. One reason for removing the POTS signal from the xDSL signal is to deny access to the POTS signal when the modem is controlled by someone other than the telephone company. Circuits have been developed which perform this splitting function and the structure and nature of the various splitter circuits form no part of the present invention other than the fact that they are at the intersection of three signal paths—the additional signals, POTS signals and the combined signals—and must be interconnected into an xDSL/POTS network in some manner.
Splitters are typically housed with the xDSL modems. However, there are problems with the splitter being located in the modem. For example, inefficient backtracking of wiring occurs. The POTS line cards and the main distribution frame where the cross-connect and protector functions are located are already in place in the central office. The network switches and equipment for the xDSL circuit are added somewhere in the central office and the POTS signal would have to be routed from somewhere in the existing POTS network to the xDSL modem to be combined with the addition signal and then back to the existing twisted-pair network. If the POTS signal is taken to the splitter in the modem and the modem needed to be repaired it could require interrupting the POTS service which is a life line service to the subscribers. Also, telephone companies may be required to provide access to their xDSL network to competitive carriers as part of regulatory changes. Having the splitter in the modem may make it inconvenient to provide such competitive access. Therefore a need exists for a means to better accommodate xDSL splitters in the central office to help avoid such backtracking, take the POTS signal out of the modem, and provide a better location for access to competitive carriers.
However, space in the existing central offices is often hard to find. Commonly the floor of central offices is already filled with existing main distribution frames. Therefore a need exists to be able to prevent such backtracking in a space saving manner taking into account existing hardware in the central office.
SUMMARY OF THE PRESENT INVENTION
The present invention eliminates POTS signal backtracking to the modem, preserves space, is usable with traditional wiring center organization practices and prevents POTS interruptions by providing a splitter assembly for mounting on the main distribution frame to connect the splitter circuit into the cross-connect field of the main distribution frame. In one aspect, the present invention provides a main distribution frame comprising a frame and a first array and a second array of terminal blocks mounted on the frame. The terminal blocks carry arrays of terminals with each terminal for termination of at least two wires for electrical connection thereof. A portion of the terminals of the terminal blocks of the first array are connected to a portion of the terminals of the terminal blocks of the second array by a plurality of first jumpers to create a cross-connect field. The assembly also comprises at least one splitter circuit located on the frame for combining/splitting xDSL signals and POTS signals carried over separate wire pairs onto/from a single wire pair. The circuit has a first pair of contacts for connection to a wire pair carrying the POTS signal, a second pair of contacts for connection to a wire pair carrying the xDSL signal, and a third pair of contacts for connection to a wire pair carrying the combined POTS and xDSL signals. At least one of these pairs of contacts is connected to a pair of the terminals of one of the terminal blocks.
Another aspect of the present invention provides a terminal block assembly for mounting to a main distribution frame comprising a terminal block having an array of terminals there through with each terminal for termination of two wires thereto for electrical connection thereof The assembly also comprises at least one splitter circuit for combining/splitting first and second signals onto/from a single telephone wire pair, the circuit having a first pair of contacts for carrying the first signals, a second pair of contacts for carrying the second signals, and a third pair of contacts for carrying the combined first and second signals. At least one of the pairs of contacts is connected to a pair of the terminals of the terminal block.
In a further aspect of the present invention, a splitter assembly is provided comprising a terminal block having an array of terminals therethrough with each terminal having a front end and a rear end. The array of terminals is divided into a POTS field with the front ends of the terminals for being connected to POTS lines from a central office, an xDSL field with the front ends of the terminals for being connected to xDSL lines, and a jumper field with the front ends of the terminals for being connected to jumpers. The assembly also comprises at least one xDSL splitter circuit having POTS contacts connected to the rear ends of the terminals in the POTS field, xDSL contacts connected to the rear ends of terminals in the xDSL field, and jumper contacts connected to the rear ends of the terminals in the jumper field.
The present invention eliminates POTS signal backtracking to the modem by taking the splitter out of the modem and moving it to the main distribution frame where POTS lines from the central office are cross-connected with the outside plant lines. The present invention also preserves space by being locatable on existing main distribution frames without violating clearance requirements. It is also usable with traditional wiring center organization practices and being usable with known main distribution frames and terminal blocks, craftspeople can use existing tools and procedures at a familiar location. The present invention prevents POTS interruptions that may be caused by having POTS signal taken to a modem that may need to be repaired or replaced.
REFERENCES:
patent: 3801873 (1974-04-01), Stumpf et al.
patent: 3904936 (1975-09-01), Hamrick, Jr. et al.
patent: 3947732 (1976-03-01), Cwir
Cwirzen Casimir
Guenther Andreas
Slotnick Barry G.
CCS Holdings, Inc.
Isen Forester W.
Storm Donald L.
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