FR2536228A1 - MANUAL CHANNEL TESTING DEVICE OF A FIBERGLASS SUBSCRIBER OPTICAL LINE WITH WAVELENGTH BIDIRECTIONAL MULTIPLEX - Google Patents

Abstract

MANUAL TEST DEVICE OF AN OPTICAL FIBERGLASS SUBSCRIBE LINE. IN THE PLACE OF TRANSMISSION, A KEY 2 PRODUCES THE OPTICAL TRANSMISSION OF INFORMATION CONSTITUTED BY SYNCHRONIZATION WORDS, USING A LOCKING CIRCUIT WHICH ALLOWS THE CONTROL OF LASER TRANSMITTER 1 ONLY DURING A PERIOD WITHOUT OPERATION. AT THE REMOTE END OF THE CHANNEL, THE SYNCHRONIZATION WORDS ARE DETECTED, THEN THE LOGICAL SIGNAL "DSE" IS DELIVERED AND IF NECESSARY INDICATED BY A LIGHT-DRIVE LED. A WAITING CIRCUIT 9 ALLOWS THE "DSE" SIGNAL TO BE TRANSPORTED TO ANOTHER WAVELENGTH, ON A RESERVED TRACK OF A MULTI-TRACK SYSTEM, TO THE POINT WHERE THE TEST HAS BEEN LAUNCHED.

Description

253622 Z

  The present invention relates to a device for manually testing the channels of a fiberglass subscriber optical line with bidirectional multiplex by wavelength, in which the line

  subscriber includes the series coupling of an HF transmitter (conver-

  parallel-series weaver), an electro-optical converter

  (laser transmitter), an opto-electric converter and a receiver

  HF transmitter (serial-parallel converter).

  The use of wavelength multiplex fiberglass transmission channels in the subscriber's connection area imposes more and more complex measurement and testing techniques to determine the precise function of the various channels of the subscriber. transmission. Maintenance personnel must be able to obtain a "good-bad" indication with simple means, simply giving them an insight into the functionality of the optical transmission channel and

  wavelengths transmitted by the latter.

  The subject of the invention is a device which makes it possible, with simple means, to obtain an overview of the functionality of the transmission channels allocated to the various wavelengths on a single cable.

  optical subscriber line operating in wavelength multiplexing.

  According to an essential characteristic of the invention, via a key and a locking circuit, which

  does not allow the control of the laser transmitter (electrical converter

  that during a period without operation, the laser transmitter is connected and a permanent SYNC information, delivered by a device of the transmitter HF (serial-parallel converter), is

  transmitted, detected at the far end of the subscriber channel after

  opto-electric version in the HF receiver (serial converter-

  parallel), then sent as a "DSE" logic signal and

  transmitted backwards on a lane of a multi-channel system.

  The testing of the functionality of each transmission channel assigned to an optical wavelength is performed during the duration of pressing a corresponding key (on the transmitter), then

  ends with the release of said key.

  Other features and advantages of the invention will be

  better understood using the detailed description below and

  annexed drawings in which: FIG. 1 shows the connection devices of a laser transmitter; Figure 2 shows the devices at the far end of the transmission channel for injecting the DSE signal into the multipath system; and FIG. 3 shows the complete devices at the beginning and at the

end of the transmission channel.

  In FIG. 1, the logic signals derived from the operating state of the laser transmitter 1 (criterion: threshold current of the laser) and the function of the key 2 are combined in the latter by a known RS latch and not shown. The result of the combination produces the logic signal "test" The circuit

  producing the logic signal "test" includes an output OR,

  putting the simulation of the 2 key function from other sources.

  The function of key 2 is inactive as long as the transmitter

  laser 1 is in use, that is, the threshold current is flowing.

  The triggering of the channel crank test is indicated to the personnel by a light-emitting diode (not shown) on

the laser transmitter 1 to try.

  A cable is used in a known manner, as shown in FIG.

  1, between the RF transmitter 7 and the corresponding electro-optical converter

  (laser transmitter 1) for transmission of data and bit frequencies (4 and 5) Line 6 is used for the transmission of the signal

  logic "test" backwards and causes two functions with -

  self-maintaining the HF transmitter 7 during the operation of the key a) connection of the HF transmitter 7 via the input e / a,

  b) delivery of a permanent SYNC triggered by the DS input.

  (The data output is inhibited as long as permanent SYNC is delivered.) The transmission of a permanent SYNC means that the complete time multiplex frame, generated in the HF transmitter 7, is occupied.

  by a synchronization word at each time slot.

  FIG. 2 represents, by way of example, the embodiment for the wavelengths λ 1 and λ 2. The permanent SYNC signals for the wavelength λ 1 are detected at the far end of the transmission channel X

  Optoelectronic conversion then comes into the converter 10.

  The latter transmits the information D transmitted in series and the bit frequency BT of accompaniment, produced using a PLL (phase lockel loop phase control loop), the converter

  series-parallel downstream (HF-11 receiver) with the correct identification

  respondent of the time frame and permanent SYNCs The signal

  "EHR" logic is the result of the identification of permanent SYNCs.

  The output of the circuit delivering the logic signal "DSE" comprises an OR operator, which makes it possible to join to a node 8 the signals "DSE" coming from several transmission channels which function

  at different wavelengths (X 29 X 3 for example).

  The logic signal "DSE" is transmitted to a waiting circuit 9, assigned to the wavelength channel X In the presence of the "DSE" signal, the output e / a of the standby circuit 9 connects the RF transmitter 7 In this state, the RF transmitter 7 produces a time multiplex frame, starting with a synchronization block. In this frame, the multiplexer FW-S 13 couples via the holding circuit.

  9 a multi channel MIC system in particular, with 30 channels in the case in question.

  dere (MIC 30) Standby circuit 9 stores the signal DSE "for the duration of the test in an 8 k bit / s channel of the system HIC 30, reserved for the transmission" DSE "The data flow D, The RF transmitter HF 7, which also contains the signal "DSE", is transmitted with the bit frequency BT to the electro-optical converter 1 (laser transmitter), but a key 2 assigned to the laser transmitter 1 also allows start a test ("croissant") directly on the converter

  electro-optical t (laser transmitter), as previously described.

  When the key triggers the test, the time frame transmitted on the wavelength channel A 4 is continuously filled by

synchronization words.

  As shown in FIG. 3, the information transmitted towards the rear is received by the electro-optical converter 1 Oa,

  then processed in the series-parallel converter 11 downstream.

  When the transmitted information contains the "DSE" signal in an 8 kbit / s channel of a PCM system 30, said "DSE" signal is detected

  by multiplexers FW-E 13 and f W-E 14, then indicated by LED 3 a.

  When the information is constituted by synchronization words, the signal "DSE" is detected directly in the serial-parallel converter 11 and can also be indicated.

by an LED.

  As shown further in FIG. 3, however, the "DSE" signal can be used again for injection into an 8 kbit / s channel of a PCM system 30, to be transmitted by the electro-optical converter 1 (FIG. laser transmitter) at the wavelength)

  The following components are involved in this case in the

  described in Figure 2: stand-by circuit 9, multi-

  plexeur 13 (format converter SW-513) and transmitter HF-S 7.

  The invention thus makes it easy to control the function

  essential parts of a transmission channel.

  At the place of emission, a key produces the emission of information

  consisting of synchronization words, via

  of a locking circuit which allows the control of

  the laser transmitter only during a period without operation.

  At the far end of the transmission channel, said information is detected, then delivered in the form of a logic signal "DSE", and where appropriate indicated by a LE Do A holding circuit 9 also allows to transmit again the signal "DSE" at another wavelength, on a lane

  reserved for a multi-channel system, to the point where the test was launched.

  Of course, various modifications may be made by those skilled in the art to the principle and to the devices which have just been described as non-limiting examples, without

depart from the scope of the invention.

Claims (4)

claims   1 Manual test device for the channels of an optical line   Fiberglass subscriber with directional multiplex   in which the subscriber line comprises the series coupling of a HF transmitter (parallel-serial converter), an electro-optical converter (laser transmitter), an opto-electric converter and an RF receiver (serial-parallel converter), said device being characterized in that by means of a key (2) and a locking circuit, which does not allow the control of the laser transmitter (1) (electro-optical converter) that during a period without operation, the laser transmitter (1) is connected and a SYNC information, issued by a device of the RF transmitter (7) (parallel serial converter), is transmitted, detected at the far end of the subscriber channel with opto-electrical conversion (by the converter (10)) in the HF receiver (11) (serial-parallel converter), then transmitted as a "DSE" logic signal and transmitted to the back on a lane of a multi-channel system.   2 Device according to claim 1, characterized in that the criterion of the operating state of the laser transmitter (1) is   constituted by its threshold current.   3 Device according to claims 1 and 2, characterized in that   light-emitting diodes (LEDs) signal the authorization of the "test" signal triggered by the key (2) and the presence of the logic signal "DSE".   4 Device according to claims 1 to 3, characterized in that   the RF receiver (11) is equipped with a word identification of permanent synchronization ("EHR").