Patent Publication Number: US-2003223375-A1

Title: Apparatus and method for shared line testing

Description:
FIELD OF THE INVENTION  
       [0001] The present invention relates to testing apparatus and methodologies for telephone networks.  
       BACKGROUND OF THE INVENTION  
       [0002] Various types of testing apparatus and methodologies for telephone networks are known. The following U.S. patents illustrate examples thereof U.S. Pat. Nos. 5,933,776; 4,942,603 and 3,937,908.  
       SUMMARY OF THE INVENTION  
       [0003] The present invention seeks to provide improved testing apparatus and methodologies for telephone networks.  
       [0004] There is thus provided in accordance with a preferred embodiment of the present invention a testing arrangement for use in a communications network carrying POTS and data traffic in an environment wherein a splitter is located between a data subassembly and a voice subassembly on one side and a subscriber on an opposite side. The testing arrangement includes test equipment switchably connected between the splitter and the subscriber.  
       [0005] There is also provided in accordance with a preferred embodiment of the present invention a testing method for use in a communications network carrying POTS and data traffic in an environment wherein a splitter is located between a data subassembly and a voice subassembly on one side and a subscriber on an opposite side. The testing method includes switchably connecting test equipment between the splitter and the subscriber.  
       [0006] Further in accordance with a preferred embodiment of the present invention the test equipment is located in relative propinquity to the splitter and to the data subassembly and the voice subassembly and relative remotely from the subscriber.  
       [0007] Still further in accordance with a preferred embodiment of the present invention the testing arrangement also includes at least one switch interconnecting the test equipment with the splitter and the subscriber. Preferably, at least part of the switch is integrated with the splitter in a single housing.  
       [0008] Additionally in accordance with a preferred embodiment of the present invention the switch includes at least one first switch, switchably interconnecting the test equipment with a subscriber line extending from the splitter to the subscriber and at least one second switch switchably interconnecting the test equipment with the splitter.  
       [0009] Moreover in accordance with a preferred embodiment of the present invention the at least one second switch includes a pair of second switches and the splitter includes first and second frequency band filters. Preferably, each of the pair of second switches switchably interconnects one of the first and second frequency band filters to the test equipment.  
       [0010] Further in accordance with a preferred embodiment of the present invention the switch includes a high-impedance switch assembly for low interference switching between the test equipment and the subscriber line, thereby minimizing interference with live communications thereon.  
       [0011] Still further in accordance with a preferred embodiment of the present invention the test equipment includes a plurality of frequency band filters which are switchably interconnected in series between at least one test head and at least one of the subscriber lines and the splitter, thereby providing switchable testing of at least one of the subscriber lines and the splitter at a plurality of frequency bands.  
       [0012] Preferably, the switch interconnects the test equipment with the splitter and the subscriber. Additionally or alternatively at least part of the switch is integrated with the splitter in a single housing.  
       [0013] Additionally in accordance with a preferred embodiment of the present invention the switch includes at least one first switch, switchably interconnecting the test equipment with a subscriber line extending from the splitter to the subscriber and at least one second switch switchably interconnecting the test equipment with the splitter.  
       [0014] Further in accordance with a preferred embodiment of the present invention the test equipment includes a plurality of frequency band filters which are switchably interconnected in series between at least one test head and at least one of the subscriber lines and the splitter, thereby providing switchable testing of at least one of the subscriber line and the splitter at a plurality of frequency bands.  
       [0015] Still further in accordance with a preferred embodiment of the present invention the test equipment is located in relative propinquity to the splitter and to the data subassembly and the voice subassembly and relatively remotely from the subscriber.  
       [0016] There is provided in accordance with yet another preferred embodiment of the present invention a switching assembly useful in a testing arrangement for use in a communications network carrying POTS and data traffic in an environment wherein a splitter is located between a data subassembly and a voice subassembly on one side and a subscriber on an opposite side. The testing arrangement includes test equipment switchably connected between the splitter and the subscriber. The switching assembly includes at least one switch interconnecting the test equipment with the splitter and the subscriber.  
       [0017] There is also provided in accordance with a further preferred embodiment of the present invention a switching methodology useful in a testing arrangement for use in a communications network carrying POTS and data traffic in an environment wherein a splitter is located between a data subassembly and a voice subassembly on one side and a subscriber on an opposite side. The methodology includes switchably connecting test equipment between the splitter and the subscriber, including employing at least one switch for interconnecting the test equipment with the splitter and the subscriber.  
       [0018] Further in accordance with a preferred embodiment of the present invention at least part of the switch is integrated with the splitter in a single housing.  
       [0019] Still further in accordance with a preferred embodiment of the present invention the switch includes at least one first switch, switchably interconnecting the test equipment with a subscriber line extending from the splitter to the subscriber and at least one second switch switchably interconnecting the test equipment with the splitter.  
       [0020] Additionally in accordance with a preferred embodiment of the present invention at least one second switch includes a pair of second switches and the splitter includes first and second frequency band filters. Preferably, each of the pair of second switches switchably interconnects one of the first and second frequency band filters to the test equipment.  
       [0021] Further in accordance with a preferred embodiment of the present invention the switch includes a high-impedance switch assembly for low interference switching between the test equipment and the subscriber line, thereby minimizing interference with live communications thereon.  
       [0022] Still further in accordance with a preferred embodiment of the present invention the test equipment is located in relative propinquity to the splitter and to the data subassembly and the voice subassembly and relatively remotely from the subscriber.  
       [0023] There is further provided in accordance with yet another preferred embodiment of the present invention a switching matrix assembly useful with a switching assembly forming part of a testing arrangement for use in a communications network carrying POTS and data traffic in an environment wherein a splitter is located between a data subassembly and a voice subassembly on one side and a subscriber on an opposite side. The testing arrangement includes test equipment switchably connected between the splitter and the subscriber. The switching assembly includes at least one switch interconnecting the test equipment with the splitter and the subscriber. The switching matrix assembly also includes a plurality of frequency band filters which are switchably interconnected in series between the test equipment and at least one of the subscriber line and the splitter, thereby providing switchable testing of at least one of the subscriber line and the splitter at a plurality of frequency bands.  
       [0024] There is provided in accordance with another preferred embodiment of the present invention a splitter useful in a communications network carrying POTS and data traffic in an environment wherein a splitter is located between a data subassembly and a voice subassembly on one side and a subscriber on an opposite side and includes a testing arrangement. The testing arrangement includes test equipment switchably connected between the splitter and the subscriber, the splitter including at least one switch integrated with the splitter in a single housing.  
       [0025] Further in accordance with a preferred embodiment of the present invention the switch includes first and second switches arranged in series with respective high and low pass filters.  
       [0026] Still further in accordance with a preferred embodiment of the present invention the switch includes a high-impedance switch assembly for low interference switching between the test equipment and the subscriber line, thereby minimizing interference with live communications thereon.  
       [0027] Preferably the switch includes a high-impedance switch assembly for low interference switching between the test equipment and the subscriber line, thereby minimizing interference with live communications thereon.  
       [0028] There is further provided in accordance with another preferred embodiment of the present invention a switching matrix methodology useful with a switching methodology employed in a testing arrangement for use in a communications network carrying POTS and data traffic in an environment wherein a splitter is located between a data subassembly and a voice subassembly on one side and a subscriber on an opposite side. The testing arrangement includes test equipment switchably connected between the splitter and the subscriber. The switching methodology includes employing at least one switch interconnecting the test equipment with the splitter and the subscriber. The switching matrix methodology includes switchably interconnecting a plurality of frequency band filters in series between the test equipment and at least one of the subscriber line and the splitter, thereby provide switchable testing of at least one of the subscriber line and the splitter at a plurality of frequency bands.  
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0029] The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which:  
     [0030]FIGS. 1A and 1B are each a simplified block diagram illustration of a testing arrangement operative in a communications network carrying POTS and data traffic and which is constructed and operative in accordance with a preferred embodiment of the present invention;  
     [0031]FIGS. 2A, 2B,  2 C,  2 D and  2 E are each an illustration of the testing arrangement of FIG. 1A in a specific switched mode of operation for providing a specific testing functionality; and  
     [0032]FIGS. 3A, 3B,  3 C,  3 D,  3 E,  3 F,  3 G,  3 H,  3 I,  3 J,  3 K,  3 L,  3 M,  3 N and  3 O are each an illustration of the testing arrangement of FIG. 1B in a specific switched mode of operation for providing a specific testing functionality.  
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
     [0033] Reference is now made to FIG. 1A, which is a simplified block diagram illustration of a testing arrangement operative in a communications network carrying POTS and data traffic and which is constructed and operative in accordance with a preferred embodiment of the present invention. As seen in FIG. 1A, the testing arrangement resides in a Central Office environment comprising a plurality of splitters  10 , one for each subscriber line  12 , connected to each subscriber  14 , one or more voice switches  16 , each having a multiplicity of voice switch ports  18 , one for each subscriber  14 , and one or more modems  20 , each typically having a multiplicity of modem ports  22 , one for each subscriber  14 .  
     [0034] In the illustrated embodiment, each splitter  10  is coupled along a subscriber line  12  to subscriber premises  14 . The splitter  10  is additionally connected via a modem line  24  to a modem port  22  of a modem  20  and via a voice line  26  to a voice switch port  18  of a voice switch  16 . A similar arrangement may be provided in a Remote Terminal environment wherein the splitters and modems are located in a Remote Terminal along with a voice multiplexer.  
     [0035] Each splitter  10  preferably comprises a high pass filter  27 , which is connected in series along modem line  24 , and a low pass filter  29 , which is connected in series along voice line  26 . Splitters  10  may be conventional splitters, such as ‘ADSL POTS Splitter Rack-Mount Shelf’ commercially available from Corning Cable Systems, Inc. Hickory, N.C., U.S.A.  
     [0036] In the illustrated embodiment of FIG. 1A and in accordance with a preferred embodiment of the present invention, test equipment  30  is switchably connected between the splitter  10  and the subscriber  14 . As shown in FIG. 1A, the test equipment  30  is preferably connected to the subscriber line  12  at a connection junction  32  between switches  34  and  36 .  
     [0037] The test equipment  30  is preferably connected to junction  32  via a parallel switch structure, generally indicated by reference numeral  38 . Structure  38  preferably comprises a switch  40  arranged in parallel to a series combination of a switch  42  and a high impedance  44 . The high impedance  44 , which is typically in excess of 50 Kohms, may be provided by a single passive component or by any suitable impedance circuit.  
     [0038] In accordance with a preferred embodiment of the present invention, the test equipment  30  comprises a switching matrix  50  having a multiplicity of switching matrix subscriber ports  52 , typically equal in number to the number of active subscribers  14 . Each switching matrix port  52  is typically connected to a junction  32  of each subscriber line, via a switch structure  38 .  
     [0039] The switching matrix  50  also has one or more switching matrix test ports  54 , the number of which is typically substantially less than the number of switching matrix subscriber ports  52 . The switching matrix  50  is operative to multiplex the test ports  54  onto the subscriber ports  52 .  
     [0040] Connected to each switching matrix test port  54  there is preferably provided a test head  56 . The test head  56  may be a conventional test head, such as a Digitest centralized network test platform, commercially available from Tollgrade Communications, Inc., Cheswick, Pa., U.S.A., or alternatively, a model TS-200 access network analyzer, commercially available from Tektronix, Inc. of Beaverton, Oreg., U.S.A.  
     [0041] Reference is now made to FIG. 1B, which is a simplified block diagram illustration of a testing arrangement operative in a communications network carrying POTS and data traffic and which is constructed and operative in accordance with a preferred embodiment of the present invention. Similarly to the embodiment of FIG. 1A, the testing arrangement resides in a Central Office environment comprising a plurality of splitters  110 , one for each subscriber line  112 , connected to each subscriber  114 , one or more voice switches  116 , each having a multiplicity of voice switch ports  118 , one for each subscriber  114 , and one or more modems  120 , each typically having a multiplicity of modem ports  122 , one for each subscriber  114 .  
     [0042] In the illustrated embodiment, each splitter  110  is coupled along a subscriber line  112  to subscriber premises  114 . The splitter  110  is additionally connected via a modem line  124  to a modem port  122  of a modem  120  and via a voice line  126  to a voice switch port  118  of a voice switch  116 . A similar arrangement may be provided in a Remote Terminal environment wherein the splitters and modems are located in a Remote Terminal along with a voice multiplexer.  
     [0043] As distinct from the embodiment of FIG. 1A, in the embodiment of FIG. 1B, each splitter  110  preferably comprises a first high pass filter  127 , which is connected in series with a switch  128  along modem line  124 , and a first low pass filter  129 , which is connected in series with a switch  130  along voice line  126 .  
     [0044] In the illustrated embodiment of FIG. 1B and in accordance with a preferred embodiment of the present invention, test equipment  131  is switchably connected between the first high pass filter  127  and the first low pass filter  129  on one side and the subscriber  114  on an opposite side. As shown in FIG. 1B, the test equipment  131  is preferably connected to the subscriber line  112  at a connection junction  132  between the switch  134  and switches  128  and  130 .  
     [0045] The test equipment  131  is preferably connected to junction  132  via a parallel switch structure, generally indicated by reference numeral  138 . Structure  138  preferably comprises a switch  140  arranged in parallel to a series combination of a switch  142  and a high impedance  144 . The high impedance  144 , which is typically in excess of 50 Kohms, may be provided by a single passive component or by any suitable impedance circuit.  
     [0046] In accordance with a preferred embodiment of the present invention, the test equipment  131  comprises a first switching matrix  150  having a multiplicity of switching matrix subscriber ports  152 , typically equal in number to the number of active subscribers  114 . Each switching matrix port  152  is typically connected to a junction  132  of each subscriber line, via a switch structure  138 .  
     [0047] The first switching matrix  150  also has one or more switching matrix test ports  154 , the number of which is typically substantially less than the number of switching matrix subscriber ports  152 . The first switching matrix  150  is operative to multiplex the test ports  154  onto the subscriber ports  152 .  
     [0048] Connected to each switching matrix test port  154  there is preferably provided a parallel structure  156  of three testing paths  158 ,  160  and  162 . Testing path  158  includes a switch  164  and a second high pass filter  166 ; testing path  160  includes a switch  168  and testing path  162  includes a switch  170  and a second low pass filter  172 .  
     [0049] Each parallel structure  156  is connected to a second switching matrix  174 , having a multiplicity of subscriber-side switching matrix ports  175 , typically equal in number to the number of test ports  154  of the first switching matrix  150 . Each subscriber-side switching matrix port  175  is typically connected to a junction  178  of each parallel structure  156 .  
     [0050] Second switching matrix  174  is also provided with one or more test-side switching matrix ports  180 , each of which is connected to a test head  184 . The test head  184  may be a conventional test head, such as a Digitest centralized network test platform, commercially available from Tollgrade Communications, Inc., Cheswick, Pa., U.S.A., or alternatively, a model TS-200 access network analyzer, commercially available from Tektronix, Inc. of Beaverton, Oreg., U.S.A.  
     [0051] In an improved implementation, switching matrix  150  is actually broken into sub-segments, some of which are integrated into the splitter  110 .  
     [0052] Reference is now made to FIGS. 2A, 2B,  2 C,  2 D and  2 E, each being an illustration of the testing arrangement of FIG. 1A in a specific switched mode of operation for providing a specific testing functionality.  
     [0053] As seen in FIG. 2A, in a first mode of operation in testing a subscriber line designated by reference numeral  100 , switches  34  and  36  are closed and switches  40  and  42  are open. In this mode of operation, the communications network operates normally and no testing takes place.  
     [0054] As seen in FIG. 2B, in a second mode of operation in testing a subscriber line designated by reference numeral  100 , switches  34 ,  36  and  42  are closed and switch  40  is open. In this mode of operation, the test equipment  30  is connected through high impedance  44  to subscriber line  100 , enabling monitoring of the subscriber line  100  without interruption to normal operation of the communications network.  
     [0055] As seen in FIG. 2C, in a third mode of operation in testing a subscriber line designated by reference numeral  100 , switches  34  and  40  are closed and switches  36  and  42  are open. In this mode of operation, the test equipment  30  is connected directly to the subscriber line  100  and is disconnected from the splitter  10 . This enables testing the integrity of the subscriber line  100  and subscriber equipment.  
     [0056] As seen in FIG. 2D, in a fourth mode of operation in testing a subscriber line designated by reference numeral  100 , switches  36  and  40  are closed and switches  34  and  42  are open. In this mode of operation, the test equipment  30  is connected to the splitter  10  and disconnected from the subscriber  14 . This enables testing the integrity of the subscriber side of the splitter  10  as well as emulation of subscriber equipment.  
     [0057] As seen in FIG. 2E, in a fifth mode of operation in testing a subscriber line designated by reference numeral  100 , switches  34 ,  36  and  40  are closed and switch  42  is open. In this mode of operation, the test equipment  30  is connected to subscriber line  100 , enabling testing of the subscriber line  100  during operation of the communications network.  
     [0058] Reference is now made to FIGS. 3A, 3B,  3 C,  3 D,  3 E,  3 F,  3 G,  3 H,  3 I,  3 J,  3 K,  3 L,  3 M,  3 N and  3 O, which are each an illustration of the testing arrangement of FIG. 1B in a specific switched mode of operation for providing a specific testing functionality.  
     [0059] As seen in FIG. 3A, in a first mode of operation in testing a subscriber line designated by reference numeral  200 , switches  128 ,  130  and  134  are closed and switches  140  and  142  are open. In this mode of operation, the communications network operates normally and no testing takes place.  
     [0060] As seen in FIG. 3B, in a second mode of operation in monitoring a subscriber line designated by reference numeral  200  using a parallel structure  300 , switches  128 ,  130 ,  134 ,  142  and  168  are closed and switches  140 ,  164  and  170  are open. In this mode of operation, the test equipment  131  is connected through high impedance  144  to subscriber line  200 , enabling monitoring of the subscriber line  200  without interruption to normal operation of the communications network.  
     [0061] As seen in FIG. 3C, in a third mode of operation in testing a subscriber line designated by reference numeral  200  using a parallel structure  300 , switches  128 ,  130 ,  134 ,  140  and  168  are closed and switches  142 ,  164  and  170  are open. In this mode of operation, the test equipment  131  is connected to subscriber line  200 , enabling testing of the subscriber line  200  during operation of the communications network.  
     [0062] As seen in FIG. 3D, in a fourth mode of operation in testing a subscriber line designated by reference numeral  200  using a parallel structure  300 , switches  134 ,  140  and  168  are closed and switches  128 ,  130 ,  142 ,  164  and  170  are open. In this mode of operation, the test equipment  131  is connected to subscriber line  200 , enabling testing of the subscriber line  200  and subscriber equipment.  
     [0063] As seen in FIG. 3E, in a fifth mode of operation in testing a subscriber line designated by reference numeral  200  using a parallel structure  300 , switches  128 ,  140  and  168  are closed and switches  130 ,  134 ,  142 ,  164  and  170  are open. In this mode of operation, the test equipment  131  is connected to modem line  124 , enabling testing of the subscriber side of the first high pass filter  127  and operation of the modem  120 .  
     [0064] As seen in FIG. 3F, in a sixth mode of operation in testing a subscriber line designated by reference numeral  200  using a parallel structure  300 , switches  130 ,  140  and  168  are closed and switches  128 ,  134 ,  142 ,  164  and  170  are open. In this mode of operation, the test equipment  131  is connected to voice line  126 , enabling testing of the subscriber side of the first low pass filter  129  and operation of the voice switch  116 .  
     [0065] As seen in FIG. 3G, in a seventh mode of operation in testing a subscriber line designated by reference numeral  200  using a parallel structure  300 , switches  128 ,  134 ,  140  and  168  are closed and switches  130 ,  142 ,  164  and  170  are open. In this mode of operation, the test equipment  131  is connected to subscriber line  200  and to the modem line  124 , enabling testing of the subscriber line when the voice switch  116  is disconnected from the communications network.  
     [0066] As seen in FIG. 3H, in a eighth mode of operation in testing a subscriber line designated by reference numeral  200  using a parallel structure  300 , switches  130 ,  134 ,  140  and  168  are closed and switches  128 ,  142 ,  164  and  170  are open. In this mode of operation, the test equipment  131  is connected to subscriber line  200  and to the voice line  126 , enabling testing of the subscriber line when the modem  120  is disconnected from the communications network.  
     [0067] As seen in FIG. 3I, in a ninth mode of operation in testing a subscriber line designated by reference numeral  200  using a parallel structure  300 , switches  128 ,  130 ,  140  and  168  are closed and switches  134 ,  142 ,  164  and  170  are open. In this mode of operation, the test equipment  131  is connected to voice line  126  and to the modem line  124 , enabling testing of central office equipment and connections when the subscriber line  200  is disconnected from the communications network.  
     [0068] As seen in FIG. 3J, in a tenth mode of operation in testing a subscriber line designated by reference numeral  200  using a parallel structure  300 , switches  128 ,  134 ,  140  and  170  are closed and switches  130 ,  142 ,  164  and  168  are open. In this mode of operation, the test equipment  131  is connected to the subscriber line  200  and to the modem line  124 , enabling testing of the subscriber line when the voice switch  116  is disconnected from the communications network without disrupting data communication along the subscriber line  200 .  
     [0069] As seen in FIG. 3K, in a eleventh mode of operation in testing a subscriber line designated by reference numeral  200  using a parallel structure  300 , switches  130 ,  134 ,  140  and  164  are closed and switches  128 ,  142 ,  168  and  170  are open. In this mode of operation, the test equipment  131  is connected to the subscriber line  200  and to the voice line  126 , enabling testing of the subscriber line when the modem  120  is disconnected from the communications network, without disrupting voice communication along the subscriber line  200 .  
     [0070] As seen in FIG. 3L, in a twelfth mode of operation in testing a subscriber line designated by reference numeral  200 , switches  130  and  134  are closed and switches  128 ,  140  and  142  are open. In this mode of operation, the modem  120  and the test equipment  131  are disconnected from the network, enabling isolation of faults in the modem line  124 .  
     [0071] As seen in FIG. 3M, in a thirteenth mode of operation in testing a subscriber line designated by reference numeral  200 , switches  128  and  134  are closed and switches  130 ,  140  and  142  are open. In this mode of operation, the voice switch  116  and the test equipment  131  are disconnected from the network, enabling isolation of faults in the voice line  126 .  
     [0072] As seen in FIG. 3N, in a fourteenth mode of operation in monitoring a subscriber line designated by reference numeral  200  using a parallel structure  300 , switches  130 ,  134 ,  142  and  168  are closed and switches  128 ,  140 ,  164  and  170  are open. In this mode of operation, the modem  120  is disconnected from the network and the test equipment  131  is connected through high impedance  144  to subscriber line  200 , enabling monitoring of the subscriber line  200  without interruption to normal operation of the voice communications network.  
     [0073] As seen in FIG. 3O, in a fifteenth mode of operation in monitoring a subscriber line designated by reference numeral  200  using a parallel structure  300 , switches  128 ,  134 ,  142  and  168  are closed and switches  130 ,  140 ,  164  and  170  are open. In this mode of operation, the voice switch  116  is disconnected from the network and the test equipment  131  is connected through high impedance  144  to subscriber line  200 , enabling monitoring of the subscriber line  200  without interruption to normal operation of the data communications network.  
     [0074] It is appreciated that other modes of operation may also be provided by the apparatus and methodology of the present invention.  
     [0075] It will be appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the present invention includes both combinations and subcombinations of the various features described hereinabove as well as variations and developments thereof which would occur to a person skilled in the art upon reading the foregoing description and which are not in the prior art.