WO1993009612A1 - Systeme d'alarme et de test comportant un circuit de couplage ameliore pour une ligne principale complementaire numerique - Google Patents

Systeme d'alarme et de test comportant un circuit de couplage ameliore pour une ligne principale complementaire numerique Download PDF

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Publication number
WO1993009612A1
WO1993009612A1 PCT/US1991/008045 US9108045W WO9309612A1 WO 1993009612 A1 WO1993009612 A1 WO 1993009612A1 US 9108045 W US9108045 W US 9108045W WO 9309612 A1 WO9309612 A1 WO 9309612A1
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WO
WIPO (PCT)
Prior art keywords
test
recited
line
remote terminal
line card
Prior art date
Application number
PCT/US1991/008045
Other languages
English (en)
Inventor
David C. Bliven
Anthony Vranicar
Philip B. Vail
Gerald L. Shimirak
Julian S. Mullaney
Jan J. Erreygers
Original Assignee
Raychem Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Raychem Corporation filed Critical Raychem Corporation
Priority to PCT/US1991/008045 priority Critical patent/WO1993009612A1/fr
Publication of WO1993009612A1 publication Critical patent/WO1993009612A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M3/00—Automatic or semi-automatic exchanges
    • H04M3/22—Arrangements for supervision, monitoring or testing
    • H04M3/26—Arrangements for supervision, monitoring or testing with means for applying test signals or for measuring
    • H04M3/28—Automatic routine testing ; Fault testing; Installation testing; Test methods, test equipment or test arrangements therefor
    • H04M3/30—Automatic routine testing ; Fault testing; Installation testing; Test methods, test equipment or test arrangements therefor for subscriber's lines, for the local loop
    • H04M3/302—Automatic routine testing ; Fault testing; Installation testing; Test methods, test equipment or test arrangements therefor for subscriber's lines, for the local loop using modulation techniques for copper pairs
    • H04M3/303—Automatic routine testing ; Fault testing; Installation testing; Test methods, test equipment or test arrangements therefor for subscriber's lines, for the local loop using modulation techniques for copper pairs and using PCM multiplexers, e.g. pair gain systems
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R13/00—Details of coupling devices of the kinds covered by groups H01R12/70 or H01R24/00 - H01R33/00
    • H01R13/46—Bases; Cases
    • H01R13/52—Dustproof, splashproof, drip-proof, waterproof, or flameproof cases
    • H01R13/5216—Dustproof, splashproof, drip-proof, waterproof, or flameproof cases characterised by the sealing material, e.g. gels or resins
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B3/00—Line transmission systems
    • H04B3/02—Details
    • H04B3/03—Hybrid circuits
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B3/00—Line transmission systems
    • H04B3/02—Details
    • H04B3/46—Monitoring; Testing
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q1/00—Details of selecting apparatus or arrangements
    • H04Q1/02—Constructional details
    • H04Q1/028—Subscriber network interface devices
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q1/00—Details of selecting apparatus or arrangements
    • H04Q1/02—Constructional details
    • H04Q1/03—Power distribution arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q1/00—Details of selecting apparatus or arrangements
    • H04Q1/18—Electrical details
    • H04Q1/20—Testing circuits or apparatus; Circuits or apparatus for detecting, indicating, or signalling faults or troubles
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R13/00—Details of coupling devices of the kinds covered by groups H01R12/70 or H01R24/00 - H01R33/00
    • H01R13/46—Bases; Cases
    • H01R13/52—Dustproof, splashproof, drip-proof, waterproof, or flameproof cases
    • H01R13/5213—Covers

Definitions

  • circuit shown in Fig. 2 largely eliminates feedback signals into the receiver, it still attenuates incoming signals by about 1/2, due to the voltage divider. It is desirable to retain the signal cancellation properties of the circuit shown in Fig. 2 while also achieving an improved incoming signal.
  • the system includes a remote terminal emulator at the central office facilities, the remote terminal emulator emulating output of the remote terminal with a predefined data pattern; and means for comparing a response of the line card to the emulated output so as to detect failures in the line card.
  • the test system may also include a voice frequency emulator, the voice frequency emulator
  • the test system includes testing of the
  • test access port is also disclosed, especially for use in conjunction with the remote
  • test access port in one embodiment.
  • the test access port includes, for example, a male plug and female RJ11 socket.
  • Such connectors include tip and ring connections on, for example, the third and fourth terminals of the socket and plug.
  • a male, dummy plug is provided for installation in the female test socket when the socket is not being used for attachment of test equipment.
  • the male plug shorts or shunts the tip connection of the female RJ11 to, for example, the first terminal of the female RJ11 socket.
  • the male dummy plug also shorts the ring connection of the female RJ11 socket to, for example, the sixth terminal of the RJ11 socket.
  • the first and sixth terminals of the female socket are then connected electrically via, for example, a terminal block, to the wires leading into a home, office, or other subscriber location.
  • the arrangement allows access to the female test socket for maintenance operations while allowing the system to be more effectively sealed from environmental contaminants during normal operations.
  • the female plug a region
  • Fig. 1 shows a generic 2-to-4 wire transmission system
  • Fig. 4 is an overall block diagram of a remote terminal (RT) according to one embodiment of the
  • Fig. 5 shows a schematic of a 2-to-4 wire hybrid coupling circuit according to one embodiment of the invention
  • Fig. 6 shows a schematic of the 2-to-4 wire hybrid coupling circuit according to another embodiment of the invention.
  • Fig. 10 illustrates the RT emulator in greater detail
  • Fig. 11 illustrates the voice frequency
  • Fig. 12 illustrates the LC emulator in greater detail
  • Fig. 14 illustrates the alarm status interface in greater detail
  • Figs. 15a to 15m are flow charts illustrating the LC/RT microprocessor code
  • Figs. 16a and 16b are overall block diagrams illustrating the master control software architecture
  • Fig. 19 is an isometric view of the RT housing with open access doors
  • Fig. 20 is a detailed fron view of one embodiment of the customer and telephone company
  • Fig. 21 is a mechanical illustration of the test access port at the RT or other subscriber equipment.
  • MTS Telephone Services
  • the system uses ISDN 2B1Q line format to transport the signal, is line powered, and includes various self-test capabilities.
  • the ISDN 2B1Q line format supports two 64 kbps voice channels and a single 16 kbps data channel, as well as additional signalling overhead over a single twisted pair.
  • the data channel is partially used for system overhead functions and to support maintenance and alarm capabilities of the system.
  • the system includes a digital subscriber line (DSL) 100, connected at the subscriber end to a Remote Terminal (RT) 102, and at the central office end 112 to a Line Card (LC) 104.
  • DSL digital subscriber line
  • RT Remote Terminal
  • LC Line Card
  • the remote terminal supports the connection of up to two analog POTS lines 106a and 106b connected to subscriber equipment 108, and two auxiliary lines 107a, 107b for continuity lines (used in, for example, burglar alarms).
  • Each of several line cards 104 are connected to the exchange 109 in the central office by two analog subscriber lines 110a, 110b.
  • Each line card also has two additional auxiliary ports 113a, 113b.
  • the shelf controller communicates with the line cards via a single serial line through a backplane with a 4.8 kbps asynchronous RS-232, also referred to as the shelf bus (SB) 116.
  • the shelf controller serves to monitor and communicate with the line cards.
  • Up to, for example, 30 shelf controllers communicate with one master controller (MC) 118, over an RS-485, synchronous serial line running at, for example, 48 kbps, also referred to as the frame bus 120.
  • the purpose of the master controller is to allow local or remote control and alarm and test functions for the line sets.
  • the master controller can be controlled from a front panel 411 or a central office interface (OS/NE) 414, via an X.25 connection.
  • the master controller also has an additional synchronous serial port RS-232 known as the craft interface 413 for maintenance purposes and has various central office alarms 416.
  • Fig. 4 is a block diagram of a remote terminal (RT) 102 according to one embodiment of the invention.
  • the RT would be placed in, for example, a home, office or other subscriber facility for transmission and/or reception of voice or data signals over the single twisted pair line 100.
  • a plurality of phones or other subscriber equipment would utilize analog signals
  • a conventional two-wire DSL 100 which may be the type commonly leading into households, offices, or the like provides input/output to the RT.
  • the signals transmitted over the DSL could either be a telephonic voice or data signal from the LC.
  • the DSL signal representing in digital form a voice or data signal, enters a two-wire to four-wire line transformer 202 for isolation and for impedance matching via a maintenance termination unit 406.
  • the voice or data signal entering the line transformer 202 is an 80 ksymbols/sec (i.e., kbaud/sec) signal having one of four voltage levels (2B1Q). While the invention is illustrated herein with regard to the preferred
  • the signal from the line 2w/4w transformer 202 enters an ISDN Echo Cancellation-Quaternary (IECQ) chip 204 via line 203.
  • the 80 ksymbols/sec 2B1Q ANSI line protocol signal contains 160 kbits/sec of information and the IECQ chip 204 converts the 80 ksymbols/sec signal into a 160 kbits/sec binary signal.
  • the 160 kbits includes 16 kbits of control information and 144 kbits of user data.
  • the ICC operates on a clock signal (CLK) at, for example, about 520 kHz and a frame control signal (FSC) at, for example, about 8 kHz.
  • CLK clock signal
  • FSC frame control signal
  • the ICC chip 206 Over a one-wire serial bus 213, the ICC chip 206 sends 8 bits of data on one channel, 8 bits of data on the other channel, 8 bits of control, and 8 bits of signal data to Codec Filter (SICOFI) 210, and then repeats, permitting substantially simultaneous
  • SICOFI 210 converts the binary bits for each channel into analog voice or data signals in which frequency and amplitude are modulated.
  • the analog signals are then transmitted over lines 209 to Subscriber Line Interface Circuits (SLIC's) 212a and 212b.
  • SLIC's 212a and 212b are four-wire to two-wire converters and control the power available for utilization by the subscriber's phone or other communication device by superimposing the analog AC signal on DC such as 48 or 24 v. DC.
  • Conventional analog information is provided to subscriber phones from the SLIC's over lines 214a and 214b.
  • Outgoing signals from the subscriber are processed in a similar but reverse method from incoming signals.
  • analog signals enter SLIC's 212a and 212b for two-wire to four-wire conversion via lines 215.
  • Signals from SLIC's 212a and 212b enter SICOFI 210 via lines 209 for analog-to-binary 8-bit word conversion.
  • These 8-bit words are, thereafter, converted in ICC 206 into a binary stream containing 160 kbits/sec of user information (144 kbits of user data plus 16 kbits of line control) for input to IECQ 204 via line 205.
  • IECQ 204 converts the 160 kbits/sec signal to an 80 ksymbols/sec quaternary signal for transmission to telephone company equipment over the twisted pair 100.
  • Fig. 5 shows a preferred embodiment of the 2-to 4-wire conversion circuit 202. As compared with the circuit shown in Fig. 2, 2 additional "wings" or coils have been added to the primary side of transformer T 1 and the connections of R D1 and R F1 have been somewhat
  • R F1 remains coupled to the central "original" winding and R D1 s is now coupled to the ends of the new, additional coils of T 1 .
  • R F1 is again set to match the load impedance Z L so as to provide proper source impedance.
  • R F2 and Z R are chosen so that the sum of 2R F2 + Z R is between 5 and 10 times the sum of 2R F1 + Z L .
  • Z R is set so that V Ref will be 1.2 to 1.5 times larger than V prime .
  • v Feedback X ⁇ V Prime given that X is the ratio between V Feedback and V prime .
  • Y as previously defined, equals V Ref /V prime .
  • V Rec V Feedback .
  • V Rec V Prime X ⁇ Y/(X+Y)
  • V Rec (V Prime /2) 2X ⁇ Y/(X+Y).
  • V Feedback /V pri ⁇ ne 3 and V Ref /V pri ⁇ ne equals 1.5.
  • the signal strength of the received signals is increased by 6 db as compared with the strength of received signals in the circuit shown in
  • Microprocessor 60 Intel 80C51, 87C51 or 80C49
  • the shelf control 114 is comprised of a microprocessor such as those listed in the table
  • Figs. 8a and 8b illustrate test and alarm equipment for the digital added main line system in conjunction with abbreviated versions of the master control (MC), RT, and LC.
  • Test and alarm services are provided to both the central office line card 104 and the remote terminal 102 by master test and alarm system 118.
  • the system is compatible with metallic line testers such as the MLT, 4TEL and conventional pair gain test
  • PGTC controllers
  • the line card has a single button on the front panel for lamp test.
  • the line card 104 has a variety of LED's 407 to indicate the system states. In one embodiment they include the following:
  • - aux2 used to indicate status of auxiliary 2
  • the shelf controller has two buttons for input by a user, i.e., alarm cutoff (used to silence alarm); and lamp test (used to test lamps). Depressing both buttons simultaneously clears any outstanding alarms.
  • test - Query status of a channel including test status, block error counts
  • the front panel includes an alphanumeric display element and a keypad 415, with keys for 0-9, up cursor, down cursor, left cursor, right cursor, alarm cutoff, test, status, special function, enter, and escape (level up).
  • the operator is able to perform the following:
  • test and alarm system tests the functionality of the entire system as well as various subsets of the entire system and alerts a user or
  • craftsman of any problems This enables detection of not only a failure in the digital added main line, but also definition of the source of the failure. Definition of the location of any failure enables the dispatch of a craftsman specific to the problem at hand. For example, if the problem is in the twisted pair between the COT and the RT, a line repairman may be dispatched, while a craftsman skilled in the repair of electronic components may be dispatched if the problem is located in the COT or the RT.
  • the DAML Master Control monitors and controls all other DAML subsystems including SC and LC subsystems. By polling all active SC's, abnormal conditions can be detected by the MC and reported to a Central Office Alarm System (COAS).
  • COAS Central Office Alarm System
  • PGTC and MLT test requests are detected and test procedures are initiated by the MC on the selected subscriber line. The tests are performed by the MC test and a DAML
  • a Remote Maintenance Terminal can, in preferred embodiments, be
  • RMT remote maintenance terminals
  • test and alarm hardware is illustrated in conjunction with the LC 104, the RT 102, and master control 118 in Fig. 8a.
  • the RT is provided with a maintenance
  • MTU 406 may be, for example, two voltage-sensitive switches which close when the voltage reaches a given level (manufactured by, for example, Tycor).
  • RT test termination equipment 412 is provided, including, for example, absorbent and reflective loads.
  • Data concentrator/shelf control 114 is provided for management of message
  • test microprocessor(s) communicate with phone company
  • Line 414 may, for example, provide an indication of a failure of a channel to the telephone company directly.
  • a digital- to-analog converter (DAC) 427 serves to convert various analog signals to digital (and the reverse) to service microprocessor(s) 402, voltage source current monitor 418 and VF board 422.
  • test lines are connectable via the SC to various portions of the MC. They are test input (IN), test output (OUT), and test DSL (DSL).
  • the VI board is connectable to all three, while the RT emulator is connectable to OUT and IN, the VF board is connectable to IN, the LC emulator is connectable to DSL, and the PGTC interface is connectable to all three.
  • Fig. 8b illustrates aspects of the MC in greater detail.
  • the MC in one embodiment, is mounted in a rack-mount chassis with an industry standard STD-Bus. According to one specific implementation of the
  • Intel 8088 CPU and modeled against the IBM PC/XT. Its peripheral devices are mapped according to the IBM PC I/O map except for two additional timer/counters (Timer 1 and Timer 2).
  • the actual CPU on board in one embodiment is an NEC V20 or Intel 8088 operating at e.g., 8 MHz. Its maximum on-board memory is 512 kbytes of combined ROM and RAM.
  • Board 436 is configured as a master processor in the STD-Bus.
  • the STD-Bus allows for a multi-processor environment with one master and many slave processors.
  • the particular devices discussed above are merely illustrative of those which could be utilized in conjunction with the invention and strike a balance of cost and operating performance. Naturally a wide array of more or less sophisticated devices could be utilized without departing from the scope of the
  • this SBX adapter is furnished with a
  • Zendex communication module based on the Zilog 8530 communication controller 439 which offers the HDLC synchronous formats.
  • board 436 In the MC, board 436, hereafter referred to as the MC Application Processor, is used to handle all application tasks such as status monitoring, alarm handling, test request handling, and LC coefficient supervision. In addition, it handles low throughput RS232C communications to the MC Front Panel and the Craft terminal. Board 438, hereafter referred to as the MC Communications Processor, is used to handle the communication requirements of the Frame communication (MC to SC), the OS/NE, and the E2A.
  • Relay K1 applies the selected voltage to the line labeled Test DSL in Fig. 8a (DSL)
  • relay K3 applies the selected voltage to the line labeled Test Out (Out) in Fig. 8a
  • relay K3 applies the selected voltage to the line labeled Test In (In) in Fig. 8a.
  • the RT emulator 420 is used to generate signals similar to that which would be produced by the RT.
  • the RT emulator is used for testing of the LC, for testing of the LC emulator, and the like, using signals from the voice frequency board.
  • a test signal is injected by the VF board to the LC while the RT emulator is commanded to connect absorbent and reflective loads.
  • the resultant reflected signals from the line under test are then evaluated to identify any failures in operation of the LC.
  • test system By enabling selection of connecting the RT to either the Test DSL or Test Output lines, it is possible for the test system to perform a self test.
  • Self test of the MC is accomplished by connecting the RT emulator to the Test DSL line while the LC emulator is similarly connected. Accordingly, tests of the test system may be performed in the same manner as tests of the actual LC and RT.
  • the RT emulator requires no separate power supply such as with the actual RT since it is located at the CO.
  • the RT offers a load equivalent to the real RT with load circuit 616.
  • load 616 offers selection between one of several loads such as 5 and 33 mA to simulate real loads in the RT power supply for testing of the power feed and/or current limiters in the LC.
  • absorbent and reflective loads may be emulated by the SICOFI under control of the MC.
  • VF Voice Frequency/OSC Monitor
  • OSC/monitor 422 produces, for example, a simulated voice signal which is transmitted to the RT. From an evaluation of the amount of the reflected signal returned to the LC by absorbent loads 428 and reflective loads 431 in the RT it is possible to determine the overall function of the system.
  • absorbent load it is intended to mean herein, for example, a 600 ohm load.
  • Fig. 11 illustrates the voice frequency OSC/monitor in greater detail.
  • the address decoder 702 and the data buffer 704 of the VF board are connected to the STD bus 502. Depending upon the data obtained from the bus, the board operates relays K1, K2, and K3 via latches and drivers 708.
  • Function generator 710 is a waveform generator capable of generating a constant 20 Hz signal or
  • the specific output of the function generator is selected by way of relay K3.
  • the 20 Hz output is selected, it is passed through driver 712 and, thereafter, to the test input line for the ring test function of the MC.
  • the sweep function is selected, the signal passes through driver 714, transformer 716, and, thereafter, to either the Test Input line or the LC Emulator, depending upon the selection of either the K1 or K2 relays.
  • Loop current detector 718 is used for detection of loop current and is used to detect a condition in which the LC has seized because the phone is off the hook. For evaluation of returned signals, the reflected voltage is passed through a filter 720, RMS converter 722 and, thereafter, to the DAC on the MC.
  • the LC emulator 424 produces a test signal or signals which emulate the actual LC from the voice frequency OSC/monitor 422, and transmits the signal to the actual RT or RT emulator. At least one of these test signals is in the voice frequency bandwidth. The system then measures the reflective signals at various terminations for a
  • FIG. 12 illustrates the LC emulator in greater detail.
  • Fig. 13 illustrates the PGTC interface 426 and the drop emulator 432 herein in greater detail.
  • the PGTC is connected to the standard bus and inputs an address-to-address decoder 902 and data decoder 904, respectively.
  • the data input to the data transceiver are transmitted to PIA 906 such as a model no. 8255 made by Intel.
  • PIA 8255 drives relay drivers 910 and 912 which control the interface with relays.
  • the tip and ring of the DC test pair are connected to the DSL and the line card is connected to the RT emulator.
  • the test system can do a metallic test of the real pair and the PGTC does a channel test of the line card connected to the RT emulator.
  • the MC connects the DC test pair to the DSL by closing the appropriate relay and connects the line card to the RT emulator by disconnecting the line card from the DSL and connecting the RT emulator to the TEST OUTPUT line.
  • the MC When these connections are made the MC will ground the appropriate SLEEVE lead to signal that the necessary connections are made.
  • the PGTC Upon receipt of the SLEEVE signal the PGTC sends a LOCK signal and removes the PROCEED signal to the carrier system, indicating that all connections have been completed.
  • the loop testing system removes the positive voltage from the tip of the test trunk the PGTC completes the connection of the test trunk from the MC to the DC test pair (otherwise referred to as a "golden pair"). Removal of the LOCK signal indicates to the MC that testing has been
  • the MC When an MLT test is detected by the LC, the MC will connect to the test pair of the MLT system. There are then two options:
  • transceiver input address and data information from the
  • Operational software for the RT microprocessor 208 has been developed for use with, e.g., an Intel 80C51 microprocessor, although it will be apparent that the invention could be applied to a wide variety of such processors.
  • Operational software has been developed for use in the microprocessor 360 in the line card. This code has been used in the Intel 80C51. Again, however, a wide variety of microprocessors could be used herein without departing from the scope of the invention.
  • the system first initializes the various pieces of hardware and software at step 1105. The system then begins a main loop 1106 through which the system repeatedly cycles until the system is disconnected from power.
  • the interrupt service clock initiates a section of code 1117 which performs routine operations needed during operation of the LC.
  • Fig. 15g illustrates the process 1114 for transmitting outgoing messages in the main loop.
  • the system determines if a message needs to be sent and, if not exits back to the main loop. If a message needs to be transmitted at step 1140 the system sets up for transmitting the message and at step 1141 tests to see if a test response is due. If so, the system adds the data and returns to the main loop. If not, the system tests at step 1142 to determine if a model
  • the RT SICOFI coefficients are set up within the main loop at step 1154. Maintenance messages are then processed at step 1155 and a test request (if present) is processed at step 1156. Watch dog timers are set at step 1157 and the system then idles until an interrupt is received at step 1158.
  • the software preferably includes application modules interacting with lower-level hardware drivers architectured in a structured manner.
  • the glue preferably includes application modules interacting with lower-level hardware drivers architectured in a structured manner.
  • Subservient modules to the self-test supervisor include a CPU board verifier 1255, a power supply verifier 1257, and a test subsystem verifier 1259.
  • the CPU board verifier is a normal PC board test. A test of the power supply is conducted in the power supply verifier.
  • the System Manager continues the cold start procedure. Part of this procedure may be prompting the system operator to enter configuration data via the system console. For example, PGTC selected test procedure.
  • SC's which respond to the STATUS REQUEST are analyzed to determine the status of their LC's. The information for all active LC's and SC's is recorded.
  • RT Emulator Handler Line Set Handler, LC Test Handler, and RT Test Handler.
  • Each test module is given the START TEST command. Upon test completion, the corresponding modules respond with a message further qualifying the test outcome, whether passed or failed, and a test report.
  • the Coefficient Supervisor 1212 handles the support to special line coefficients, coefficient
  • Coefficient Manager will verify if there are special coefficients for the specified LC which may require loading.
  • a message is sent to the remote LC unit via the corresponding SC.
  • the Coefficient Manager will compare the loaded coefficients with the one sent. If both transmitted and received versions match, the loading is considered successfull. Otherwise, the process is started again.
  • the Coefficient Supervisor will retry coefficient loading several times. If after this time it is still unsuccessfull, a warning message is sent to the system console indicating the problem condition.
  • the MC Communication Processor (MCCP) software includes communication link control modules which
  • ISR Service Routines
  • a Router module which provides the network layer functions interfaces with all communication drivers and is capable of routing message packets from channel to channel.
  • the routing is dependent on a routing table which matches destination module name with channel number. Thereby, messages need only be coded with a destination and the Router module would identify and route the message to the proper channel. At the end of the routed channel where the destination module is expected to reside.
  • Fig. 17b illustrates the select shelf step 1204 in greater detail.
  • the system broadcasts a message to all shelves to disconnect from the test bus.
  • the system connects the selected shelf to the test bus by transmitting an appropriate message to the SC.
  • the system then performs a channel test; this checks the performance of both voice channels.
  • the channel test includes the steps of selecting the line, issuing a test request, performing an absorbent test, performing an on-hook test, testing the ringer, performing a reflective test, and deselecting the line.
  • Fig. 17c illustrates the channel test 1206 in greater detail.
  • the system checks whether the DSL of the selected line set is up (i.e., if the IECQ's are linking). If the DSL is not up the system waits for a short time and trys again for a selected number of times.
  • the system then performs a test of line A.
  • the system initially selects the desired line at step 1320 by transmitting a message to the selected LC. This also disconnects the line card from the exchange.
  • a delay of, for example, 250 ms, may be allowed at step 1322 to allow for the LC to get the message and for confirmation to get back to the MC that the line is selected.
  • the confirmation of the LC is checked and the result is logged.
  • the system then proceeds to test the selected line.
  • the VSCM board Tip and Ring voltages are set to 0 volts.
  • a delay of, for example, 15 ms may be allowed for the lines to settle.
  • the system connects the VS board 418 to the input of the LC.
  • the system compares the reflected voltage with a reference value(s)) and, at step 1346, logs the result.
  • the absorbent load is disconnected from the RT test bus by transmitting a message to the LC. This creates the on-hook condition. The seize relays will open as the RT will see on-hook.
  • Fig. 17f illustrates the ring test portion of the channel test.
  • the system resets the VS board to 0 volts on Tip and Ring.
  • the 20 Hz output on the VF board is selected and a delay of, for example, 25 ms is allowed for settling of the system.
  • the VS board is connected to the test input line.
  • the 20 Hz input on the VS board is connected to the ring and the tip remains at zero volts.
  • the system checks the ring detect message from the RT and logs the result at step 1364.
  • the 20 Hz signal from the VF board to the VS board is then disconnected at step 1366.
  • the VF frequency board is reset to frequency sweep. After a delay of, e.g., 25 ms for settling of relays and output voltage, the VS board is disconnected from the test input line. After an
  • a reflective test is performed.
  • the reflective test is illustrated in Fig. 17g.
  • the RT Upon ringing the RT will connect the reflective short termination to the test bus. This connection will close the seize relays at the LC because the RT sees an off-hook state.
  • the VF board is connected to the test input line after a delay of 150 ms.
  • the system checks for the confirmation of reflective connection of the RT. The reflected voltage from the DAC input is tested at step 1374. After a delay of, e.g., 100 ms for settling of A/D, the system compares the reflected voltage with a reference value(s) at step 1376 and logs the result.
  • Fig. 17h illustrates the LC test procedure 1214 in greater detail. It is assumed below that the Shelf is already selected.
  • the system initializes the RT emulator with a low current load.
  • the system connects the DSL output of the selected LC to the TEST OUTPUT line by transmitting a message to the selected LC.
  • the system connects the RT Emulator to the TEST OUTPUT line.
  • the system then performs a DSL power feed test at step 1377.
  • the system performs a channel test, which has been described in greater detail in relation to Figs. 17c to 17g.
  • the system disconnects the DSL output of the selected LC from TEST OUTPUT by transmitting a message to the selected LC.
  • the system disconnects the RT-Emulator from the TEST OUTPUT line.
  • Fig. 17i illustrates the DSL test 1216 in greater detail.
  • the DSL of the selected LC is connected to TEST DSL by transmitting a message to the selected LC. This disconnects the DSL from the LC.
  • the DSL test is then performed at step 1396 and the system checks to see if the RT is connected at step 1373.
  • the system connects the tip line of the VSCM board to the TEST DSL and does not connect the ring line.
  • the VSCM then applies a low voltage to the tip line, with the ring open. This test is conducted with a sufficiently low voltage such that the MTU in the RT is not effected and the voltage-sensitive switches therein do not close.
  • the system measures the tip current and, at step 1357 the system compares with a reference value.
  • a similar sequence of steps is conducted for the ring line with the tip line open. A high current at either step is indicative of the line in question being grounded.
  • step 1361 the system connects both tip and ring to Test DSL and applies a low voltage to the tip line, with the ring to zero volts, and the current is measured at step 1363.
  • the system compares the measured current to a reference, and repeats at step 1367 with a low voltage at ring and tip at zero volts. A high current in either of these steps is indicative the tip and ground line shorted to each other.
  • a load resistor such as a 200 K resistor in series with the diode is supplied.
  • the diode is blocking.
  • step 1398 the system disconnects the DSL and, at step 1400, disconnects the VS board and logs the results.
  • Fig. 17j illustrates the RT test 1218 in greater detail.
  • the system connects the DSL of the selected LC to TEST DSL by transmitting a message to the selected LC.
  • the system connects the LC-Emulator to TEST DSL.
  • the system checks whether the DSL of the selected line set is up by checking whether the IECQ chips are linking. If the DSL is not up, the system waits for a period of time and trys again. If the DSL is still not up, the status is logged in the test status database for the specific SC/LC, time stamped, and the test is exited. These steps are necessary because the Line Set may be trying to link. Especially when the LC Emulator or RT Emulator are used, it will take some time before they are linking. If the DSL link is up, the system continues.
  • the system selects one of the lines for test.
  • the LC Emulator is set to the selected line.
  • the system reads the line status of the LC Emulator. It is not relevant to issue a test request for the LC Emulator.
  • the system connects the selected line of the RT and the absorbent load to the RT test bus by sending a message to the RT. The system then selects the frequency sweep on the VF board at step 1315.
  • the system connects the VF board to the LC Emulator. After a delay (e.g., 50 ms) the system checks the confirmation of the RT and logs the result at step 1319. The system then reads the reflected voltage from the DAC input. After another delay (100 ms) for settling of A/D the system compares the reflected voltage with a reference value(s) at step 1321 and the results are logged.
  • the absorbent load is disconnected from the RT test bus by sending a message to the RT.
  • Fig. 17l illustrates the on-hook test.
  • step 1327 the system reads the reflected voltage from the DAC input and, after a delay (100 ms) for settling of A/D, compares the reflected voltage with reference value(s) at step 1329. The results accordingly are logged and the VF board is disconnected from LC emulator at step 1331.
  • the system then performs a ring test, which is illustrated in Fig. 17m.
  • a ring request is sent to the RT at step 1333.
  • the system checks the ring detect message from the RT and logs the result at step 1335.
  • the system then performs a reflective test, as illustrated in Fig. 17n.
  • Upon ringing the RT will connect a reflective short termination to the test bus at step 1337.
  • the system connects the VF board to the LC Emulator.
  • a check at step 1341 confirms reflective connection of the RT.
  • the system reads the reflected voltage from the DAC input and, after a delay (100 ms) for settling of A/D, compares the reflected voltage with reference value(s) at step 1345. The results are logged and the system disconnects the VF board from the LC Emulator at step 1347.
  • the system disconnects the reflective short termination from the RT test bus, and disconnects the selected line from the RT test bus by sending a return to normal message to the RT.
  • the RT test is then repeated for the other line at step 1351.
  • the system disconnects the DSL of the selected LC from the TEST DSL by transmitting a message to the selected LC and disconnects the LC-Emulator from the TEST DSL line. The status of the RT is then logged for the specific SC/LC and time stamped.
  • Fig. 17o illustrates the DSL power feed test 1377 in greater detail.
  • the system checks to make sure the selected DSL is up. If not, the system waits for a selected time at step 1381 and retries for a selected number of times. If the DSL is up, the system connects the voltage source board to the Test Output line at step 1383.
  • the system measures the tip and ring voltage, and at step 1387 compares to a reference value, and logs the result.
  • the system then connects a high current load in the RT emulator, and again measures the tip and ring voltages at step 1391.
  • the system compares the values with a reference value and logs the result.
  • the system disconnects the high load in the RT emulator and disconnects the RT emulator from the test output line.
  • the RT electronics will often be located in an unprotected environment at a user location. Access to various portions of the RT is desirably limited.
  • Figs. 18 and 19 illustrate an enclosure which will find particular application with the RT disclosed herein.
  • the enclosure includes an RT electronics case 1402, a telephone company equipment compartment 1404, and a customer line compartment 1406.
  • the three portions of the enclosure are mounted to, for example, a wall, pole, or any other convenient location via a mounting plate 1408.
  • the electronics case houses the PCB containing the various electronic components used in D/A and A/D conversion and generally illustrated in Fig. 4.
  • the telephone company equipment compartment contains one or more terminal blocks connected to a drop wire 1410 containing one or more DSL's.
  • compartment houses one or more customer blocks for connection of subscriber equipment lines 1412.
  • the electronics case is preferably a modular plug-in unit which lifts directly off of and away from the lower portions of the enclosure, as indicated by the arrow 1414.
  • a door over the customer line enclosure is hinged to drop down in the direction of arrow 1416 and then out in the direction of arrow 1418.
  • a door over the telephone company equipment enclosure 1404 is similarly hinged.
  • a skirt 1420 extends outward and downward from the electronics case and over the telephone company equipment compartment and the customer line compartment so as to prevent the influx of rainfall and the like in one embodiment.
  • the entire case is sized to fit over the doors, rendering the skirt unnecessary. Downward movement of the doors to the two compartments 1404 and 1406 allows overhang of the skirt 1420 while also allowing access to the two compartments without removal of the case 1402.
  • Fig. 19 illustrates the enclosure in greater detail with the case 1402 lifted from its base and with the two compartment doors open.
  • the case 1402 is shown partially cut away.
  • the case 1402 encloses PCB 1422 which contains the various components shown in Fig. 4 along with their interconnections.
  • Interconnections to the terminal blocks in the telephone company compartment 1404 and customer compartment 1406 are made via a multiple conductor plug 1424 and socket 1426 of the type well known to those of skill in the art.
  • the PCB is
  • the multiple conductor socket is at least partially filled with an environmental sealant.
  • sealants are available for this use, including, for example, hot melts, but preferably including epoxies and dielectric gels such as urethanes, silicones, and styrene-ethylene-butylene-styrenes, including those disclosed in U.S.
  • Preferred gels used in conjunction with the present invention include those having a cone penetration value of 50 to 350 ⁇ 10 -1 mm, preferably 100 to 300 ⁇ 10 -1 mm, and most preferably 100 to 250 ⁇ l0 -1 mm. Preferred gels also have an ultimate
  • the bottom portion of the case 1402 is sealed with a plate 1458, as shown in the cut-away portion of Fig. 19. Above the plate 1458, the case is further sealed with hot melt 1460.
  • the case is filled with between 1/64" and
  • Hot melt or mastic preferably having good adhesion to metal properties at low temperatures (e.g., 0oC) and not becoming brittle at low temperatures.
  • Hot melt suitable for this purpose is preferably type number S1149 made by Raychem Corporation.
  • the bottom of the case is sealed with hot melt although gels such as those described in the above incorporated patents may be used in some embodiements.
  • the door of the telephone company compartment 1428 is mounted to a frame 1430 with drop hinges 1432. Drop hinges allow the door to move both upward and downward, as well as allowing the door to swing open and shut.
  • the door 1438 includes a lip 1434 which extends under a customer equipment door 1436 when the doors are in the closed position. This prevents encroachment of water from rain, as well as other environmental encroachments.
  • Door 1428 is provided with a protected fastener 1438 which engages the frame 1430 at a mounting point 1440.
  • the protected fastener is designed to limit customer access to the telephone company compartment 1404.
  • customer compartment door 1436 is fastened to the frame 1430 with a conventional and readily utilized fastener 1444, such as a conventional screw, bolt, wing nut, friction fitting, or the like. Accordingly, a customer is provided ready access to compartment 1406, while only the telephone company has ready access to compartment 1404.
  • case 1402 is held to the frame 1430 by only the socket 1426, although in some embodiments one or more bolts or other fasteners 1446 extend through the frame and into the case. As shown, one of the bolts is connected to the frame in the
  • Terminal block 1448 serves as an interface between socket 1426 and a twisted pair wire entering the customer facility.
  • the terminal block 1448 is a Raychem DTerminatorTM, Protected DTerminatorTM, or the like.
  • Customer terminal block 1450 is mounted to frame 1430.
  • Customer terminal block 1450 preferably includes both screwed terminal connections 1452 and modular, plug-in connections 1454.
  • Customer terminal block 1450 serves as an interface between socket 1426 and wires leading to subscriber equipment in the customer's facility.
  • both of terminal blocks 1448 and 1450 are protected with terminal block caps filled with a gel such as the gels used in the socket 1426.
  • the modular plug in connections 1454 such as RJ11
  • connections include a male and female side.
  • the male and female portions are connected and telephone signals to the subscriber equipment are transmitted over two or more wire conductors therein.
  • the male side is disconnected and the test equipment, such as a phone used for testing, is plugged into the female side of the plug.
  • the male plug in the RT is reinserted into the female side, reestablishing a connection with the subscribers
  • the enclosure provides a customer ready access to portions of the RT which require customer service. At the same time, the enclosure provides reliable
  • the RT electronics are compartmentalized in the case 1402 such that when a failure of the RT electronics is
  • a switch 405 detects opening of the telephone company compartment and reports such conditions via the test system.
  • the customer compartment and/or the telephone compartment may be provided with additional environmental sealing using, for example, the gels mentioned in conjunction with the socket 1426.
  • a strip of environmental sealant (a section of which is illustrated by reference numeral 1462) is provided around the edges of the frame where the frame meets the doors 1428 and 1436.
  • a strip of environmental sealant is provided along the top perimeter of the frame where the frame will meet the case (as illustrated by the section of sealant 1464).
  • Sealant 1466 may optionally be provided in the case 1402 against the PCB 1422 to provide shock resistance and corrosion resistance for the components therein.
  • the enclosure In normal operation, the enclosure is utilized in the configuration shown in Fig. 18. If the subscriber needs access to the customer compartment, the fastener 1444 is disengaged, the door is dropped to the lower limits of the hinges, and the door is swung open. The subscriber removes terminal covers (if any) from the terminal block and performs any required operations to the customer compartment. Access to the telephone company compartment is restricted due to the fastener 1438. Similarly, removal of the case 1402 and attendant electronics is restricted because the subscriber cannot access the fastener 1446 in the compartment 1404.
  • the case is released from the frame 1430 by releasing the fasteners 1446.
  • the entire case including the enclosed electronics and gel sealant, is removed from the frame and replaced with a new case and electronics.
  • the case is sealed to the frame with a gasket or seal, and lifts away from the frame without the internal electronics.
  • the gels described in the above-incorporated patents are used for sealing and are placed in a trough which is engaged by the bottom of the case. The RT PCB or any particular component thereon is then appropriately replaced or serviced.
  • the frame is preferably self draining to weep holes or the like, preventing
  • the enclosure and its various components may be made from any one of a wide variety of materials.
  • Preferred among such materials are sheet metal, plastic, and the like.
  • Fig. 20 illustrates one embodiment of the bottom portion of the RT enclosure in greater detail.
  • the telephone company compartment encloses terminal block 1448.
  • the terminal block 1448 is preferably formed with an upper portion 1602 and a lower portion 1604.
  • the upper portion is shown in Fig. 20 with a cover thereon which encloses one or more of the above-described gels.
  • the lower portion 1604 provides a connection to the drop wires.
  • the telephone company compartment further includes a maintenance interface 1606 such as a five-pin plug, as well as indicator lights 403.
  • a maintenance interface 1606 such as a five-pin plug, as well as indicator lights 403.
  • terminal block 1452 is shown with a gel-filled cover 1608 thereon.
  • wires need not extend from the male side of the RJ11 connector, using the "dummy" male connector described below.
  • a grasping means such as a stiff plastic string 1610, is connected to the male side of the "dummy" RJ11 test connection, allowing it to be easily removed from the female side.
  • Fig. 21 illustrates the test port 1454 in greater detail according to one embodiment of the
  • the port includes a female, preferably RJ11, socket or jack 1702 and a male plug 1704.
  • the male plug is
  • the male dummy plug is removed and a conventional RJ11 connector is inserted into the female side 1702.
  • a RJ11 plug which contains six connectors such as 1706a, 1706b, 1706c, 1706d, 1706e, and 1706f.
  • the third contact 1706c is the ring wire which provides signals which ultimately are generated at the CO.
  • the fourth contact 1706d is the tip contact which provides signals which are ultimately generated at the CO.
  • the first contact 1706a is connected to the ring line which leads into the home, office, or other subscriber facility.
  • the sixth contact 1706f is
  • the male RJ11 plug 1704 is referred to herein as a "dummy" connection because it does not contain wires that extend from the male connection to subscriber equipment or elsewhere.
  • a first conductor 1710 such as a copper or aluminum strip or wire 1710 inside the male RJ11 electrically connects the first pin 1706a and the third pin 1706c of the female RJ11 when the male plug is inserted into the female plug.
  • a second conductor 1712 in the male RJ11 electrically connects the fourth pin 1706d and the sixth pin 1706f of the female RJ11 when the male plug is inserted.
  • the conductors 1712 and 1710 could take on any one of a number of forms such as wires, deposited metal, separate metal strips, or the like. Accordingly, when the dummy male RJ11 is inserted into the female RJ11, a tip connection and ring connection between the subscriber facility and the CO (via the RT in the
  • gels such as those described in the above incorporated patents are provided in one or more of the inside of the female RJ11 1701 , the inside portion of the male RJ11 1704, a trench 1714 around the perimeter of the female RJ11, and/or a trench formed by a cap 1716 around the male RJ11.
  • the gel is shown only in the trench 1714 and in the cap 1716.
  • the gel is provided only in the trench surrounding the female socket, while the cap around the male plug forms an edge lip which engages the gel in the female trench when the two are mated. In this most preferred
  • the user has minimal contact with gel in the test plug.
  • sealing means as taught in EPO Publication No. 0 213 874, 03/11/1987 ("Corrosion Protection Apparatus) may be utilized, which is
  • Figs. 22a and 22b illustrate the electrical connections made during test and normal operations modes, respectively, with the RJ11 arrangement herein.
  • a conventional RJ11 plug is used to connect test equipment to the tip and ring lines ultimately leading to the CO.
  • the tip and ring lines leading to the home or office are
  • the system described above provides multiple-line telephone services to a user over a single twisted pair without the need to provide a battery or other current source at the RT.
  • the system maintains the line power within the limits proscribed by TR-TSY-000057 standard All in a standby mode and AIII during active line use.
  • the RT microprocessor is operated at a relatively slow speed (e.g., 4 MHz or less) as compared to the LC processor, which may be operated at relatively higher speeds (e.g., 11 MHz or more) for power conservation at the RT, particularly during "idle" periods.
  • Table 3 illustrates the power usage of the various components in the system according to one
  • Table 3 illustrates that by use of the method/apparatus disclosed herein, in the standby mode the system is well within AII limits. Specifically, about 430 milliwatts may readily be provided in a typical system while remaining in AII limits, while only 373 milliwatts are needed during standby. Similarly, the 2302 milliwatts needed for

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Power Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Dispersion Chemistry (AREA)
  • Monitoring And Testing Of Exchanges (AREA)

Abstract

Système de test utilisé avec un dispositif servant à transmettre et à recevoir des signaux de transmission téléphoniques multiples par l'intermédiaire d'une seule paire téléphonique torsadée (100). Le système convertit un signal analogique provenant d'une station de commutation locale (112) en un signal de 80 Ksymboles/seconde pour le transmettre par l'intermédiaire d'une paire téléphonique au moyen d'une carte de ligne (104). Un terminal distant (102) reconvertit le signal de 80 Ksymboles/seconde en signal analogique classique s'utilisant dans un téléphone classique (108), un appareil de télécopie ou autre type d'équipement semblable. L'équipement de test séparément la totalité du système, la partie de carte de ligne dudit système, la partie de terminal distant du système, ainsi que la paire téléphonique torsadée. L'invention décrit également un circuit de couplage hybride amélioré (202) comportant de 2 à 4 fils. Le circuit amélioré possède 2 bobines supplémentaires latérales reliées au transformateur de sortie connu, lesdites bobines supplémentaires améliorant la force du signal reçu et annulant efficacement la réaction provenant de l'amplficateur de sortie.
PCT/US1991/008045 1991-10-30 1991-10-30 Systeme d'alarme et de test comportant un circuit de couplage ameliore pour une ligne principale complementaire numerique WO1993009612A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/US1991/008045 WO1993009612A1 (fr) 1991-10-30 1991-10-30 Systeme d'alarme et de test comportant un circuit de couplage ameliore pour une ligne principale complementaire numerique

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Application Number Priority Date Filing Date Title
PCT/US1991/008045 WO1993009612A1 (fr) 1991-10-30 1991-10-30 Systeme d'alarme et de test comportant un circuit de couplage ameliore pour une ligne principale complementaire numerique

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Cited By (8)

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WO1996029841A1 (fr) * 1995-03-20 1996-09-26 Raychem Corporation Multiplexeur enfichable
EP1073247A2 (fr) * 1999-07-30 2001-01-31 Lucent Technologies Inc. Procédé de préqualification de lignes d'abonnés pour services de données à haut débit
FR2798031A1 (fr) * 1999-08-30 2001-03-02 St Microelectronics Sa Transformateur asymetrique pour ligne telephonique
EP1370879A2 (fr) * 2001-02-15 2003-12-17 2Wire, Inc. Systeme et procede de localisation d'incidents pour extenseurs de boucle dsl
US6804349B1 (en) 1999-08-30 2004-10-12 Stmicroelectronics S.A. Hybrid transceiver circuit
EP1780928A1 (fr) * 1994-11-30 2007-05-02 Qualcomm, Incorporated Procédé et appareil pour tester un canal de communication numérique à des taux de données variables ou fixes
US7672450B2 (en) 2004-09-09 2010-03-02 Calix Networks, Inc. Network interface device enclosure
CN105264730A (zh) * 2013-06-10 2016-01-20 三菱电机株式会社 车辆间传输装置

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US4748651A (en) * 1987-06-12 1988-05-31 Keptel, Inc. Multiline transmission line test receptacle with provision for testing each line
US4924489A (en) * 1988-04-12 1990-05-08 British Telecommunications Public Limited Company Customer line tester
US4979209A (en) * 1987-12-30 1990-12-18 Keptel, Inc. Individual subscriber line module

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Publication number Priority date Publication date Assignee Title
US3689710A (en) * 1969-10-17 1972-09-05 Int Standard Electric Corp Two-wire to four-wire conversion circuit for a data switching center
US4595802A (en) * 1983-11-29 1986-06-17 Northern Telecom Limited Hybrid circuit
US4598396A (en) * 1984-04-03 1986-07-01 Itt Corporation Duplex transmission mechanism for digital telephones
US4748651A (en) * 1987-06-12 1988-05-31 Keptel, Inc. Multiline transmission line test receptacle with provision for testing each line
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Cited By (15)

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Publication number Priority date Publication date Assignee Title
EP1780928A1 (fr) * 1994-11-30 2007-05-02 Qualcomm, Incorporated Procédé et appareil pour tester un canal de communication numérique à des taux de données variables ou fixes
WO1996029841A1 (fr) * 1995-03-20 1996-09-26 Raychem Corporation Multiplexeur enfichable
US5917814A (en) * 1995-03-20 1999-06-29 Raychem Corporation SLC-96 plug-in multiplexer
EP1073247A3 (fr) * 1999-07-30 2001-02-28 Lucent Technologies Inc. Procédé de préqualification de lignes d'abonnés pour services de données à haut débit
EP1073247A2 (fr) * 1999-07-30 2001-01-31 Lucent Technologies Inc. Procédé de préqualification de lignes d'abonnés pour services de données à haut débit
KR100758832B1 (ko) * 1999-07-30 2007-09-19 루센트 테크놀러지스 인크 고속 데이터 서비스를 위한 가입자 회선들의 사전 자격부여 방법
FR2798031A1 (fr) * 1999-08-30 2001-03-02 St Microelectronics Sa Transformateur asymetrique pour ligne telephonique
EP1081873A1 (fr) * 1999-08-30 2001-03-07 STMicroelectronics SA Transformateur asymétrique pour ligne téléphonique
US6804349B1 (en) 1999-08-30 2004-10-12 Stmicroelectronics S.A. Hybrid transceiver circuit
EP1370879A2 (fr) * 2001-02-15 2003-12-17 2Wire, Inc. Systeme et procede de localisation d'incidents pour extenseurs de boucle dsl
EP1370879A4 (fr) * 2001-02-15 2006-04-26 2Wire Inc Systeme et procede de localisation d'incidents pour extenseurs de boucle dsl
US7672450B2 (en) 2004-09-09 2010-03-02 Calix Networks, Inc. Network interface device enclosure
CN105264730A (zh) * 2013-06-10 2016-01-20 三菱电机株式会社 车辆间传输装置
EP3010103A4 (fr) * 2013-06-10 2017-03-01 Mitsubishi Electric Corporation Dispositif de transmission entre véhicules
US9838057B2 (en) 2013-06-10 2017-12-05 Mitsubishi Electric Corporation Inter-vehicle communication device

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