Alarm and test system for a digital added main line

• US 5,111,497 A
• Filed: 09/17/1990
• Issued: 05/05/1992
• Est. Priority Date: 09/17/1990
• Status: Expired due to Term

• Current Assignee: Tyco Electronics Corporation (TE Connectivity Limited)
• Original Assignee: Raychem Corporation (TE Connectivity Limited)
• Inventors: Shimirak, Gerald L., Vranicar, Anthony, Mullaney, Julian S., Bliven, David C., Vail, Philip B.
• Primary Examiner(s): SCHREYER, STAFFORD
• Application Number:
  US07/584,325
• Time in Patent Office: 596 Days
• Field of Search: 379/27, 379/29, 379/442, 379/451, 379/453, 379/457, 370/14, 361/356, 361/391, 361/390, 361/393, 361/419
• US Class Current: 379/27.01
• CPC Class Codes: H01R 13/443 Dummy plugs
• CPC Class Codes: H01R 13/5216 characterised by the sealing material, e.g. gels or resins
• CPC Class Codes: H01R 2201/16 for telephony
• CPC Class Codes: H01R 24/62 Sliding engagements with one side only, e.g. modular jack coupling devices
• CPC Class Codes: H02G 15/117 for multiconductor cables
• CPC Class Codes: H04M 1/24 Arrangements for testing
• CPC Class Codes: H04M 3/245 for ISDN systems
• CPC Class Codes: H04M 3/303 and using PCM multiplexers, e.g. pair gain systems
• CPC Class Codes: H04Q 1/028 Subscriber network interface devices
• CPC Class Codes: H04Q 1/03 Power distribution arrangements
• CPC Class Codes: H04Q 1/20 Testing circuits or apparatus; Circuits or apparatus for detecting, indicating, or signalling faults or troubles
• CPC Class Codes: H04Q 2213/13003 Constructional details of switching devices
• CPC Class Codes: H04Q 2213/13034 A/D conversion, code compression/expansion
• CPC Class Codes: H04Q 2213/13096 Digital apparatus individually associated with a subscriber line, digital line circuits
• CPC Class Codes: H04Q 2213/1316 Service observation, testing
• CPC Class Codes: H04Q 2213/13162 Fault indication and localisation
• CPC Class Codes: H04Q 2213/13179 Fax, still picture
• CPC Class Codes: H04Q 2213/1319 Amplifier, attenuation circuit, echo suppressor
• CPC Class Codes: H04Q 2213/13194 Four wire connection, transmission
• CPC Class Codes: H04Q 2213/13199 Modem, modulation
• CPC Class Codes: H04Q 2213/13335 : Simulation, emulation

Abstract

A test system directed to apparatus for transmitting and receiving multiple telephone transmission signals over a single twisted pair. The system converts an analog signal from a local switching station to an 80 ksymbols/sec signal for transmission over a twisted pair by a line card. A remote terminal converts the 80 ksymbols/sec signal back into a conventional analog signal for use in conventional telephone, facsimile or other related equipment. The test equipment separately tests the entire system, the line card portion of the system, the remote terminal portion of the system, and the twisted pair.

Claims

1. A test system for a digital main line system, said digital main line system including a line card for conversion of analog signals to digital signals and a remote terminal for conversion of said digital signals to analog signals for use in subscriber telephonic equipment, said digital main line system adapted to transmit multiple telephonic signals in digital form from said line card to said remote terminal location over a single twisted pair, comprising:

a) a remote terminal emulator at central office facilities for performing a line card test, said remote terminal emulator emulating output of said remote terminal with a predefined output pattern; and

b) means for comparing a response of said line card to emulated output of said remote terminal emulator so as to detect failures in said line card.

2. The test system as recited in claim 1 further comprising a voltage source and current meter attachable to said twisted pair for performing a twisted pair test, said voltage source and current meter adapted to detect failures in said twisted pair.

3. The test system as recited in claims 1 or 2 further comprising:

a) a line card emulator for performing a remote terminal test, said line card emulator emulating output of said line card for transmission over said twisted pair; and

b) means for applying and detecting terminations at said remote terminal, so as to detect failures in said remote terminal.

4. The test system as recited in claims 1 or 2 further comprising means for performing a channel test, said means for performing a channel test comprising:

a) a voice frequency emulator, said voice frequency emulator connected to said line card for conversion to a digital signal for transmission over said twisted pair to said remote terminal; and

b) means for evaluating a returned reflected signal so as to evaluate the function of the line card, the twisted pair and the remote terminal.

5. The test system as recited in claim 3 further comprising logic means in said test system for determining a location of a failure in said line card, said twisted pair, and said remote terminal.

6. The test system as recited in claim 4 further comprising logic means in said test system for determining a location of a failure in said line card, said twisted pair, and said remote terminal.

7. The test system as recited in claim 2 further comprising a pair gain test controller interface to said test system, said interface adapted to receive test request information from a PGTC, test selected portions of said digital added main line system, and output a resistive signature to said PGTC.

8. The test system as recited in claim 1 further comprising means for serially connecting a plurality of line cards at said central office facilities to said remote terminal emulator so as to detect failures in said plurality of line cards.

9. The test system as recited in claim 2 further comprising means for serially connecting a plurality of twisted pairs to said voltage source current meters so as to detect failures in said plurality of twisted pairs.

10. The test system as recited in claim 3 further comprising means for serially connecting a plurality of remote terminals to said line card emulator so as to detect failures in said plurality of remote terminals.

11. The test system as recited in claim 1 wherein said response of said line card indicates a failure in said line card when an analog to digital conversion portion of said line card is inoperative.

12. The test system as recited in claim 3 wherein said terminations are indicative of a failure in said remote terminal when an analog to digital conversion portion of said remote terminal is inoperative.

13. The test system as recited in claim 1 further comprising an operating system interface for communicating indications of failures in said line card to a telephone company operating system.

14. The test system as recited in claim 5 wherein said logic means comprises first and second microprocessors, said first microprocessor programmed to act as an input/output control device and said second microprocessor programmed to manage tests of at least said line card.

15. The test system as recited in claim 5 wherein said means for determining a location is programmed to:

a) perform said channel test, said channel test testing the functionality of all of said remote terminal, twisted pair, and line card;

b) if said channel test is not successful, perform said line card test using said remote terminal emulator, and perform said twisted pair test using said voltage source current meter; and

c) if said twisted pair test is successful, perform said remote terminal test using said line card emulator.

16. The test system as recited in claim 15 wherein said means for detecting a location is further programmed to test whether one or more lines of said digital added main line system are in use before performing said channel test.

17. The test system as recited in claim 4 wherein said test system is programmed to perform said channel test by the steps of:

a) selecting a line;

b) disconnecting the selected line from a telephone exchange;

c) performing a test request message test;

d) performing an absorbent test of the selected line;

e) performing an on-hook test of the selected line;

f) performing a ring test of the selected line; and

g) performing a reflective test of the selected line.

18. The test system as recited in claim 3 wherein said test system is programmed to perform said remote terminal test by the steps of:

a) connecting said line card emulator to a selected line;

b) connecting a remote terminal on said selected line to an absorbent load;

c) connecting a voice frequency generator to said line card emulator; and

d) reading a reflected voltage on said selected line and comparing the reflected voltage to a reference voltage so as to determine if said remote terminal is functioning.

19. The test system as recited in claim 18 wherein said test system is further programmed to:

a) perform an on-hook test of said remote terminal;

b) perform a ring request of said remote terminal; and

c) perform a reflective test of said remote terminal.

20. The test system as recited in claim 5 wherein said test system further comprises:

a) means for applying a first voltage to a tip wire of said twisted pair;

b) means for measuring a current to said tip wire;

c) means for applying said first voltage to a ring wire of said twisted pair;

d) means for measuring a current to said ring wire;

e) means for ground said ring wire and applying said first voltage to said ring wire; and

f) means for grounding said tip wire and applying said first voltage to said ring wire; and

g) means for applying a second voltage to said tip wire, said ring wire grounded, said second voltage activating a maintenance termination unit in said remote terminal.

21. A method of testing a digital added main line, said digital added main line comprising a line card for conversion of multiple analog signals at a local exchange to digital signals for transmission over a single twisted pair to a subscriber location, and a remote terminal for conversion of said digital signals to analog signals for use by subscriber equipment, said method comprising the steps of:

a) emulating an analog signal at an input to said line card;

b) converting said emulated analog signal to a digital signal for transmission over said twisted pair to said remote terminal;

c) converting said digital signal at said remote terminal to an analog signal and retransmitting a reflected signal to said line card; and

d) comparing said reflected signal to a reference standard, a deviation from said standard indicating a failure in at least one of said line card, said remote terminal, and said twisted pair.

22. The method as recited in claim 21 further comprising the step of testing said line card, said step of testing said line card comprising the steps of:

a) connecting a remote terminal emulator to an output of said line card, said remote terminal emulator emulating a response of a functional remote terminal to digital signals from said line card;

b) emulating an analog signal at an input to said line card;

c) converting said emulated analog signal to a digital signal for transmission to said remote terminal emulator;

d) converting said digital signal at said remote terminal emulator to an analog signal and retransmitting a reflected signal to said line card; and

e) comparing said reflected signal to a reference standard, a deviation from said standard indicating a failure in said line card.

23. The method as recited in claim 21 further comprising the step of testing said twisted pair, said step of testing said twisted pair further comprising the steps of:

a) applying a first voltage to a tip wire of said twisted pair, said first voltage not activating a maintenance termination unit in said remote terminal;

b) measuring a current to said tip wire;

c) applying said first voltage to said tip wire with said ring wire grounded; and

d) measuring a current to said tip wire.

24. The test system as recited in claim 21 further comprising the step of testing said remote terminal, said step of testing said remote terminal further comprising the steps of:

a) connecting a line card emulator to said twisted pair, said line card emulator emulating output of a functioning line card;

b) connecting an absorbent load at an output of said remote terminal;

c) transmitting a signal to said remote terminal and reading a reflected voltage from said line card;

d) disconnecting said absorbent load at said remote terminal;

e) connecting a reflective termination to an output of said remote terminal; and

f) reading a reflected voltage from said line card.

25. A method of testing a digital added main line, said digital added main line comprising a line card for conversion of multiple analog signals at a local exchange to digital signals for transmission over a single twisted pair to a subscriber location, and a remote terminal for conversion of said digital signals to analog signals for use by subscriber equipment, said method comprising the steps of:

a) performing a channel test of said digital added main line, said channel test testing all of said line card, said remote terminal, and said twisted pair;

b) performing a test of said line card using emulated remote terminal output;

c) performing a test of said twisted pair; and

d) performing a test of said remote terminal using emulated line card output.

31. The enclosure as recited in claim 25 wherein said components case is secure to said at least one of said components, said components removed from said socket upon removal of said case.

26. A method of testing a digital added main line, said digital added main line comprising a line card for conversion of multiple analog signals at a local exchange to digital signals for transmission over a single twisted pair to a subscriber location, and a remote terminal for conversion of said digital signals to analog signals for use by subscriber equipment, said method comprising the steps of:

a) performing a channel test of said digital added main line, said channel test testing all of said line card, said remote terminal, and said twisted pair, said channel test comprising the steps of;

i) connecting a reflective load to an output of said remote terminal;

ii) emulating an analog signal to an input of said line card; and

iii) comparing a reflected signal at said line card to a reference value;

b) performing a test of said line card using emulated remote terminal signals, said test of said line card comprising the steps of;

i) connecting a remote terminal emulator to an output of said line card;

ii) connecting a remote terminal emulator to an output of said remote terminal emulator;

iii) emulating an analog signal to an input of said line card;

iv) comparing a reflected signal at said line card to a reference value;

c) performing a test of said twisted pair, said test of a twisted pair comprising the steps of;

i) applying a first voltage to a first wire of said twisted pair;

ii) measuring a current to said first wire;

iii) applying said first voltage to said first wire with a second wire grounded; and

iv) measuring a current to said first wire;

d) performing a test of said remote terminal using emulated line card output, said test of said remote terminal comprising the steps of;

i) emulating output of a line card to an input of said remote terminal; and

ii) comparing a reflected voltage from said remote terminal to a reference standard.

27. A test system for a digital main line system, said digital main line system including a line card for conversion of analog signals to digital signals and a remote terminal for conversion of said digital signals to analog signals for use in subscribed telephonic equipment, said digital main line system adapted to transmit multiple telephonic signals in digital form from said line card to said remote terminal over a single twisted pair, comprising:

a) a line card emulator at central office facilities for performing a remote terminal test, said line card emulator emulating output of said line card with a defined data pattern;

b) means for comparing a response of said remote terminal to emulated output of said line card emulator so as to detect failures in said remote terminal.

28. An enclosure for telecommunications equipment comprising:

a) a frame, said frame defining a limited access region and an accessible region, said limited access region comprising limited access telephone line connections, said accessible region comprising accessible telephone line connections;

b) a first cover over said limited access region, said cover permitting access to said limited access region upon release of an access restrictive fastener;

c) a second cover over said accessible region, said second cover permitting access to said accessible region upon release of a second fastener; and

d) a components case, said component case enclosing at least one electronics component for processing signals from and to said limited access telephone line connections and said accessible telephone line connections, said component attached to said accessible telephone line connections and said limited access telephone line connections with a socket and plug assembly.

29. The enclosure as recited in claim 28 wherein said components case is secured to said frame with at least one fastener in said limited access region.

30. The enclosure as recited in claim 28 wherein said at least one component for processing signals comprises a circuit board for conversion of digital signals from a twisted pair to analog signals for use in subscriber telephone equipment.

32. The enclosure as recited in claim 28 wherein said first and second covers comprise hinged doors.

33. The enclosure as recited in claim 32 wherein said components case comprises a skirt extending downward over said doors, said doors hinged to move downward away from said skirt upon release of said fasteners.

34. The enclosure as recited in claim 28 further comprising a seal for limiting ingress of environmental contaminants to said case.

35. The enclosure as recited in claim 28 wherein said components case further comprises an environmental sealing material over at least one opening thereof.

36. The enclosure as recited in claim 35 wherein said environmental sealing material comprises a hot melt.

37. The enclosure as recited in claim 36 wherein said hot melt is S1149.

38. The enclosure as recited in claim 28 further comprising a gel seal in said socket and plug assembly.

39. The enclosure as recited in claim 38 wherein said gel is selected from the group of urethanes, silicones, and styrene-ethylene-butylene-styrenes.

40. The enclosure as recited in claim 38 wherein said gel has a cone penetration value of between about 50 and 350×

10^-1 mm and an ultimate elongation of at least 50%.

41. The enclosure as recited in claim 40 wherein said gel has a cone penetration value of between about 100 to 300×

10^-1 mm.

42. The enclosure as recited in claim 40 wherein said gel has a cone penetration value of between about 100 to 250×

10^-1 mm.

43. The enclosure as recited in claim 40 wherein said gel has an ultimate elongation of at least 100%.

44. The enclosure as recited in claim 40 wherein said gel has an ultimate elongation of at least 200%.

45. The enclosure as recited in claim 28 further comprising a switch for detection of an open condition of said first cover.

46. An environmental enclosure for protection of electronic equipment used for analog to digital telephonic signals at a subscriber location, comprising:

a) a frame, said frame partially enclosing a telephone company twisted pair block and a user terminal block for connection of subscriber equipment;

b) a first hinged door for enclosing said twisted pair block, said hinged door securable to said frame with a fastener, said fastener limiting access of a subscriber to said twisted pair block;

c) a second hinged door for enclosing said block for connection of subscriber equipment, said first and said second hinged doors rotatable about an axis and slidable along said axis from a first position to a second position;

d) an electronics board case, said electronics board case electrically connectable to said block for connection of subscriber equipment and said twisted pair block with a socket and plug assembly on top of said frame, said electronics board case secured to said frame mechanically with at least one fastener accessible from a region enclosed by said first hinged door.

47. Apparatus for connecting first and second telephone lines alternately to a subscriber location and to test equipment comprising:

a) a first connection means containing first, second, third, and fourth electrical conductors, said first and second electrical conductors providing telephone signals, said third and fourth conductors electrically connectable to subscriber equipment, said connection means connectable to said test equipment; and

b) a second connection means connectable with said first connection means, said connection means comprising a first shunt conductor for connecting said first and said third conductors, and a second shunt conductor for connecting said second and said fourth conductors.

48. Apparatus as recited in claim 47 wherein said first connection means is an RJ11 socket.

49. Apparatus as recited in claim 48 further comprising said test equipment, said test equipment further comprising a RJ11 plug.

50. Apparatus as recited in claim 47 wherein said second connection means is shaped in the form of an RJ11 plug.

51. Apparatus as recited in claim 50 wherein:

a) said first connection means is an RJ11 socket;

b) said first shunt conductor electrically connects first and third terminals in said RJ11 socket;

c) said second shunt conductor connects fourth and sixth terminals in said RJ11 socket.

52. Apparatus as recited in claim 47 wherein said second connection means contains no conductors extending out of a body of said second connection means.

53. Apparatus as recited in claim 47 further comprising sealing means for environmentally protecting said first connection means.

54. Apparatus as recited in claim 53 wherein said sealing means comprises a gel in at least one of said first connection means or said second connection means.

55. Apparatus as recited in claim 53 wherein said gel has a cone penetration value of 50 to 350×

10^-1 mm and an ultimate elongation of at least 50%.

56. Apparatus as recited in claim 53 wherein said gel has a cone penetration value of 100 to 300×

10^-1 mm and an ultimate elongation of at least 100%.

57. Apparatus as recited in claim 53 wherein said gel has a cone penetration value of 100 to 250×

10^-1 mm and an ultimate elongation of at least 200%.

58. Apparatus as recited in claim 54 wherein at least a portion of said gel is located in a trench around said first connection means.

59. Apparatus as recited in claim 54 wherein at least a portion of said gel is located in a trench around said second connection means.

60. Apparatus as recited in claim 54 wherein said second connection means is a plug, said trench formed by a cap around said plug.

61. Apparatus as recited in claim 60 wherein said plug is a male RJ11 compatible plug.

62. A service module for alternately connecting subscriber tip and ring lines and service means comprising:

a) an RJ11 socket;

b) a first electrical conductor connecting a first terminal of said female RJ11 to a tip line in a subscriber location;

c) a second electrical conductor connecting a second terminal of said female RJ11 to a ring line in a subscriber location;

d) a third electrical conductor connecting a third terminal of said female RJ11 to a means for providing tip signals from a telephone switch;

e) a forth electrical conductor connecting a fourth terminal of said female RJ11 to a means for providing ring signals from a telephone switch; and

f) an RJ11 plug insertable in said female RJ11 socket, said RJ11 plug comprising;

i) a first shunt conductor for connecting said first electrical conductor and said third electrical conductor; and

ii) a second shunt conductor for connecting said second electrical conductor and said fourth electrical conductor when said RJ11 plug is inserted in said RJ11 socket.

63. Apparatus as recited in claim 62 wherein said RJ11 plug contains no conductors extending out of a body thereof.

64. Apparatus as recited in claim 62 further comprising sealing means for environmentally protecting said RJ11 socket.

65. Apparatus as recited in claim 64 wherein said sealing means comprises in at least one of said RJ11 plug or socket.

66. Apparatus as recited in claim 65 wherein said gel has a cone penetration value of 50 to 350×

10^-1 mm and an ultimate elongation of at least 50%.

67. Apparatus as recited in claim 65 wherein said gel has a cone penetration value of 100 to 300×

10^-1 mm and an ultimate elongation of at least 100%.

68. Apparatus as recited in claim 65 wherein said gel has a cone penetration value of 100 to 250×

10^-1 mm and an ultimate elongation of at least 200%.

69. Apparatus as recited in claim 65 wherein at least a portion of said gel is located in a trench around said first connection means.

70. Apparatus as recited in claim 65 wherein at least a portion of said gel is located in a trench around said RJ11 plug.

71. Apparatus as recited in claim 65 wherein said trench is formed by a cap around said plug.