Patent Publication Number: US-2004057188-A1

Title: System and method for providing telephone service restrictions

Description:
BACKGROUND OF THE INVENTION  
       [0001] As a result of regulatory changes in the telecommunications industry, incumbent local exchange carriers or “ILECs” (i.e., the traditional phone companies that often provide most or all telephone service in certain geographic areas) have opened up their telephone networks to competitive local exchange carriers (CLECs). CLECs have been given the right to “purchase” various elements of the ILECs network in order to provide telecommunications services to subscribers. The pricing of these elements can be complex and awkward to administer.  
       [0002] For example, the CLEC may purchase a “local loop” (the telephone line connecting the subscriber to the ILEC&#39;s central office) in order to offer either traditional voice telephone service or more advanced (higher speed) and more costly data services, such as DSL, ISDN, etc. The cost of the element will typically be based on the type of service that the CLEC intends to offer, with a local loop for traditional voice telephone service priced much lower than more advanced services.  
       [0003] One problem that has arisen in this environment is that a CLEC will purchase a local loop for one class of service, but later begins offering a more advanced service over that local loop. This not only deprives the incumbent phone company of revenue that it might otherwise be entitled to, but also leads to problems in the network. The more advanced services often operate at higher frequencies and use higher-powered signals, and can cause problems with other adjacent lines if the adjacent lines have not been conditioned to accommodate the higher-powered signals.  
       BRIEF SUMMARY OF THE INVENTION  
       [0004] Embodiments of the present invention are directed to a system and method for providing fault protection and service restrictions. In accordance with one embodiment of the invention, a telecommunications network is provided. The telecommunications network includes a central office and subscriber equipment. The network also includes a plurality of telecommunications lines interconnecting the central office and the subscriber equipment. The network further includes a plurality of connection devices or protectors, each protector associated with one of the telecommunications lines and, in one disclosed embodiment, for protecting the network against hazardous or undesirable signals present on the associated telecommunications lines. The network also includes a service regulating or restricting module (a filter in one embodiment) associated and integral with at least one protector, for regulating the class of service provided over the telecommunications line associated with the protector.  
       [0005] In another embodiment of the present invention, there is provided a device for protecting and regulating service over a local loop. This device includes a protector housing and a protective circuit for protecting the network against hazardous signals present on the associated telecommunications line. The device further includes electrical pins which extend from the protector housing and are used for connection to a telecommunications line at a distribution panel. In accordance with the present invention, the protector device also includes a service regulating or restricting circuit. The service regulating circuit regulates the class of service provided over the telecommunications line. This circuit can be readily designed to pass or block signals depending on the class of service.  
       [0006] In still another embodiment of the present invention, there is provided a method for regulating service over a local loop. The method involves providing a protector device for connecting to a telecommunications line and for protecting the line against hazardous signals which may pass through the line. The method also involves providing, with the protector device, a service restricting or regulating circuit for blocking certain classes of service. For example, if the CLEC has purchased the local loop for use with ADSL, the service regulating module would prevent any higher frequency signals (such as for use with VDSL) from passing through on the line.  
       [0007] Further features of the present invention, as well as the structure and operation of various embodiments of the present invention, are described in detail below with respect to the accompanying drawings. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0008] In the Figures, similar components and/or features may have the same or similar reference number or label. Further, various components of the same type may be distinguished by following the reference label with a second label that distinguishes among the similar components. If only the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label.  
     [0009]FIG. 1 is a simplified block diagram illustrating a telecommunications network, including central office equipment, a distribution panel, and outside telephone equipment, in accordance with the present invention.  
     [0010]FIG. 2 is a partial perspective view of a protector device and a distribution panel in accordance with the present invention.  
     [0011]FIG. 3 is a schematic diagram of the protector device illustrated in FIG. 2.  
     [0012]FIG. 4 is a schematic diagram of the filter circuit within the protector device of FIG. 3. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     [0013] There are numerous configurations for implementing the present invention. One such configuration is seen in FIG. 1 where, according to an embodiment of the present invention, a telecommunications network  100  includes central office equipment  102 , a distribution panel  104 , and outside telephone (subscriber) equipment  106 . As illustrated, the central office equipment  102 , the distribution panel  104 , and the outside telephone equipment  106  are interconnected by a plurality of telecommunications lines  108 ,  110 . Central office equipment  102  is conventional and mostly comprises switches, cable distribution frames, batteries, etc. Central office equipment  102  is usually located at the telephone company (ILEC) central office. Outside telephone equipment  106  is also conventional and mostly comprises subscriber devices (e.g., telephones), loops, lines, and converters, etc. Outside telephone equipment  106  may be located at a distance from the central office, such as at a subscriber&#39;s house or business.  
     [0014] The distribution panel  104  (also known as a distribution frame), is a panel which connects central office lines  108  to outside lines  110 . The central office lines  108  and outside lines  110  are connected to each other at the distribution panel using jumper wires and protector devices. While the distribution panel  104  is usually located at the central office, it should be appreciated that the distribution panel  104  may be located elsewhere in the network. The network described thus far is conventional and well known in the art.  
     [0015] Referring now to FIG. 2, there is shown a protector device  202  for use with the distribution panel  104  (only a portion of which is seen in FIG. 2). As illustrated, the protector device  202  includes a protector housing  204  and a plurality of electrical pins  206  which extend from the protector housing  204  and are used to make electrical connections at the distribution panel  104 , typically connecting one (a twisted pair) of the lines  108  to an associated one (twisted pair) of the lines  110 , at the distribution panel. While the number of pins  206  may vary (depending on the configuration of the panel  104 ), in the illustrated embodiment, there are five pins, two for connection to the central office lines  108  (tip and ring), two for connection to the outside lines  110  (tip and ring) and a grounding pin. Electrical pins  206  are inserted into connector sockets  208  at the distribution panel  104  in order for the protector device  202  to interconnect the lines at the distribution panel  104  and thereby pass signals between the central office equipment  102  and the subscriber equipment  106 .  
     [0016] While not shown in FIG. 2, it will be appreciated by those skilled in the art that at a typical distribution panel there may be hundreds (or more) of protector devices  204 , each having its pins  206  inserted at the distribution panel for connecting one of the associated central office lines to one of the outside lines at the panel.  
     [0017] The protector device  202  (also known as a protector block), is used to protect connected equipment (particularly costly equipment at the general office), from excessive voltage and/or excessive current. These hazardous or undesirable voltages and currents (usually originating outside the central office) are shunted to ground. For example, protector device  202  minimizes danger in areas which endure many lightning storms, as well as other sources of electrocution or excessive current.  
     [0018] Also in some cases, where there are circumstances when no protection is needed, the protector device  202  may merely provide electrical interconnection (of lines  108 ,  110 ) at the distribution panel, without protection circuitry for shunting hazardous signals to ground.  
     [0019] Referring now to FIG. 3, there is shown, in accordance with one embodiment of the present invention, the electrical components within the protector device  202  for protecting the network against hazardous signals present on the associated telecommunications lines  108 ,  110 . The electrical components within the protector device  202  comprise a protective circuit  302  having two gas tubes  304 , two metallic shunts  306 , and a filter circuit  308 .  
     [0020] Gas tubes  304  within the protective circuit  302  are surge suppression devices which clamp a surge voltage to a limited value. Gas tubes  304  are usually made up of two electrodes which are close together so that high voltages between the electrodes simply arc through air or other gas within the tube and are thereby shunted to ground. Metallic shunts  306  are conductors which melt (to complete an electrical path) at a predetermined excessive level of current and thereby shunt that current to ground.  
     [0021] The gas tubes  304  serve to shunt undesirable signals, usually of smaller magnitude and shorter duration. They do so repeatedly whenever such signals appear on the lines  108 ,  110 . The metallic shunts  306 , on the other hand, protect against larger and potentially more damaging signals, and once their conductive elements melt and conduct to ground, the protector device will no longer be operable to pass telephone signals between the central office and the subscriber (all signals are thereafter shunted to ground and the protector device  204  must be replaced in order for the telecommunications lines to pass telephone signals.)  
     [0022] It should be appreciated from the foregoing that the protector device  204  serves two purposes: (1) electrical connection of each central office line  108  to its associated outside line  110 , and (2) protection of the network by shunting to ground any undesirable signals/currents/voltages passing through the lines  108 ,  110  at the distribution panel.  
     [0023] The protector device  204  as thus far described is conventional. For example, a protector device as described above is sold by Corning Cable Systems, formerly Siecor Corporation, Hickory, N.C., as gas tube protector modules (6A and 7A). Such protector devices are also described in various patents, such as U.S. Pat. No. 5,909,349.  
     [0024] In accordance with one embodiment of the present invention, the protector device  202  includes filter circuit  308 . With filter circuit  308 , the protector device  202  not only protects the network against hazardous or undesirable signals, but also restricts or blocks unpermitted frequencies present on the associated telecommunications lines  108 ,  110 . The filter circuit  308  thus regulates the class of service provided over telecommunications lines  108 ,  110 , and is illustrated in more detail in FIG. 4.  
     [0025] Referring now to FIG. 4, the filter circuit  308  includes inductors  402  and capacitors  404 . Filter circuit  308  can be readily designed to pass or block frequencies depending on the class of service authorized to pass through the telecommunications lines to or from the subscriber. For purposes of illustration, the following Table 1 shows possible configurations (component values) of the filter circuit  308  for each of three possible classes of telecommunications service. It should be appreciated that various other filter configurations are possible for other classes of service (e.g., ISDN, SDSL, HDSL) using different values of capacitors and inductors, all within the scope of the present invention.  
               TABLE 1                          Filter configurations - permitted service                         POTS   ADSL   VDSL       Plain Old (traditional)   Asymmetric Digital   Very high data rate Digital       Telephone Service   Subscriber Line   Subscriber Line               C = 0.001 μF   C = 0.0008 μF   C = 0.012 μF       L = 0.20 mH   L = 0.10 mH   L = 0.06 mH                  
 
     [0026] As an example, using Table 1 and in conjunction with Table 2 below, if a CLEC has purchased a local loop for use with POTS only, the protector device  202  of the present invention can be designed—by configuring the filter circuit  308  in accordance with Table 1—to block signal frequencies above 4 KHZ. However, as a further example, if the CLEC has purchased a local loop for use with VDSL, the filter circuit can be easily configured to block only signal frequencies above 12000 kHz. Therefore, the ILEC that has sold the local loop to the CLEC would be able to regulate the usage over the local loop.  
     [0027] For purposes of illustration, the following Table 2 shows the various signal frequencies for several representative classes of service available over telecommunications lines  108 ,  110 . It should be appreciated that there are other levels of signal frequencies (for other classes of service) for which the filter circuit  308  could be designed.  
               TABLE 2                          Spectrum Management Classes                             Service Type   Frequency in kHz           POTS   up to ˜4           ADSL   between ˜25 and ˜1104           VDSL   between ˜25 and ˜12000                      
 
     [0028] Depending on the class of service “purchased” by a CLEC, the filter circuit  308  can be configured to pass and block a variety of signal frequencies. For example, if the CLEC has purchased a local loop for the purposes of using it to access POTS, which has a frequency of about 4 kHz, and ADSL, which has a frequency of between 25 kHz and 1104 kHz, the filter is configured to pass signal frequencies between 0 kHz and 1104 kHz and to block signal frequencies that are not in that range. Therefore, if the CLEC tried to circumvent the ILEC and attempted to use the local loop for a faster digital service such as VDSL, which has a frequency of between 25 kHz and 12000 kHz, the filter circuit  308  would block signal frequencies higher than 1104 kHz. Likewise if the CLEC purchased the local loop for the sole purpose of POTS, but later attempted to use the local loop as a digital subscriber line, the filter circuit  308  would block any unauthorized signal frequency above 4 kHz.  
     [0029] It can be seen from the foregoing that protector device  202  is used to connect and protect portions of a telecommunications network, such as central office lines  108 , outside lines  110  and equipment connected thereto, from excessive voltage and/or excessive current. Protector device  202  also has the functionality (filter circuit  308 ) to block unauthorized signal frequencies from the telecommunications lines  108 ,  110 .  
     [0030] While a detailed description of presently preferred embodiments of the invention have been given above, various alternatives, modifications, and equivalents will be apparent to those skilled in the art without varying from the spirit of the invention. It should be understood that various forms of network interconnection other than lines  108 ,  110  (twisted pairs) could be used to connect the central office to the outside equipment within the scope of the invention, such as wireless connections, coaxial cables, etc. It should also be appreciated that other forms of connectivity other than electrical pins  206  may be used to connect the protector device  202  to the distribution panel  104 . These other forms might include as an example (and in lieu of pins  206 ), connections such as surface contacts present on the protector device  202  with corresponding surface contacts on the distribution panel  104 , wherein the protector device  202  is clamped or otherwise held onto the distribution panel  104  (so that corresponding surface contacts are brought into electrical connection). Therefore, the above description should not be taken as limiting the scope of the invention, which is defined by the appended claims.