FR2818477A1 - ISOLATOR DEVICE FOR ADSL LINE - Google Patents

Abstract

The invention concerns an isolator device for an ADSL transparent to the line, that is the voice band and the broadband services are not affected by its insertion. Said device comprises isolating means (IS), ADSL filtering means (LPF, HPF) arranged on the telephone exchange side (AC) and means for controlling (P) said isolating means (IS) to connect or disconnect the line filtering means in accordance respectively with a first operating mode which corresponds to normal operating conditions of the line, that is digital and analog transmission of signals or a second operating mode of the line which corresponds to test measurements.

Description

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L'invention concerne un dispositif isolateur pour ligne ADSL et plus généralement xDSL (de l'acronyme Digital Subscriber Line). L'invention s'applique aux liaisons analogiques comprenant des équipements pour assurer outre les services bande étroite (téléphonie analogique ou numérique), des services large-bande basés sur les technologies xDSL. ISOLATOR DEVICE FOR ADSL LINE.

The invention relates to an insulator device for ADSL line and more generally xDSL (of the acronym Digital Subscriber Line). The invention is applicable to analogue links comprising equipment for providing bandwidth services (analog or digital telephony) in addition to broadband services based on xDSL technologies.

 Broadband service means any service transmitted in a spectral band above narrowband services (ie telephony or ISDN) in practice at frequencies above 10 KHz. Typically these are the services delivered by the xDSL network.

 In general xDSL is used to denote broadband services comprising all the technological families such as SDSL, ADSL, ADSL-lite.

 In the following we will talk about ADSL services to simplify, of course, that the invention applies to all the services mentioned above.

In general, a telephone company uses in its central measurement robots for requirements related to the supervision of its lines, when a fault is found on the line. A robot uses two types of measurements to enable localization, these measures are as follows:
The so-called open measure, which allows a frank localization and is based on the

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calcul de la capacité effective de la ligne : Effective-
Les mesures de défauts d'isolement et de boucle . pour réaliser ces dernières, le robot effectue des mesures d'isolement et de résistance de boucle R.

calculation of the effective capacity of the line: Effective-
Measurements of insulation and loop faults. to achieve these, the robot performs measurements of isolation and loop resistance R.

 Defect localization measurements by echometry.

Subsequently, two modes of operation are considered:
1. mode of transmission: the robot is unused and the filtering means are connected, the line is in normal situation and allows the transmission of analog and digital signals.

 2. Measurement mode: the robot performs one or more measurements on the considered line. In this case, it will be seen that according to the invention, the filtering means are disconnected.

 It is recalled that the deployment of ADSL technology involves the implementation of band splitter filters (or also called Splitter) side of the telephone center and the user to multiplex and separate the so-called analog signals from those related to broadband services (ADSL). These splitter generally comprise a low-pass filter referenced LPF in the following, and a Y-shaped structure as shown in FIG. 1. A high-pass filter referenced HPF is generally positioned directly

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sur la carte électronique permettant d'assurer les services ADSL.

on the electronic card to ensure ADSL services.

 In the current state of knowledge, centrally located ADSL filters available on the market are not transparent to the test measurement tools used to date.

 On the other hand, even if they were transparent to these signals, the presence of the high-pass filter positioned in the ATU-C, ADSL card of the exchange would disturb the value of the measurements made and consequently their interpretation would be erroneous.

 The development of ADSL technology has the consequence of making it impossible on the lines concerned, any subsequent maintenance procedures or location of defects as implemented by the current test robots.

 The invention relates to a device that makes compatible the implementation of ADSL or XDSL filters on the central side and the use of current measurement robots.

 This solution makes it possible, in particular when the measurement mode is activated for a line considered for testing purposes, not to have to modify the current testing tools to make them compatible with the ADSL filters.

 The device developed by the applicant allows the filters to be completely transparent to these tools, that is to say, on the one hand transparent to the transmitted signals and on the other hand not modifying the measured values.

 With this device, the interpretation of the measurements therefore remains similar, that the line is equipped with a

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filtre ADSL (placé côté terminal) ou non. Seule exception, la mesure des résistances de boucle impose que la ligne soit terminée par une résistance non nulle. Le résultat de la mesure doit donc tenir compte de sa valeur.

ADSL filter (placed on the terminal side) or not. The only exception is the measurement of loop resistances, which requires the line to be terminated by a non-zero resistance. The result of the measurement must therefore take into account its value.

 The invention relates more particularly to an insulator device for ADSL line transparent line, that is to say that the voice band and the broadband services are not affected by its insertion; this device comprises isolation means, ADSL filtering means arranged on the central telephone side and control means of said isolation means for connecting or disconnecting the filtering means of the line respectively according to a first or a second operating mode of the line.

des moyens de commande de connexion ou déconnexion des filtres, activés par ces moyens de détection. According to another characteristic of the invention, the control means comprise: two output terminals connected respectively to the wires of the line upstream of the filtering means, means for detecting the first and second operating mode of the line and,

connection control means or disconnection filters, activated by these detection means.

 According to another characteristic of the invention, the detection means of the operating mode comprise a circuit for charging and discharging a capacitor from the supply voltage of the line, said circuit being intended to supply a control voltage.

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aux moyens d'isolation ; le dispositif ne consommant que pendant le deuxième mode opératoire de la ligne c'est à dire pendant les mesures de test (charge et décharge du condensateur).

insulation means; the device consuming only during the second operating mode of the line, ie during the test measurements (charge and discharge of the capacitor).

 According to a preferred embodiment, the charge and discharge circuit of a capacitor comprises said capacitor connected in series with at least one relay and a first and second transistor for supplying said control voltage.

 The capacitor charging and discharging circuit further includes respective bias circuits for the first and second transistors.

 According to another characteristic of the invention, the isolation means comprise a plurality of contacts placed on the line wires for connecting or disconnecting the filters while ensuring the continuity of said line.

 The first and second transistors are connected so as to allow, according to their on-state or blocked, to open and close the contacts placed on the line.

 According to a preferred embodiment, the connection means, disconnection of the ADSL filtering means comprise a diode bridge for biasing said means to make them independent of the polarization of the line.

 According to one embodiment, the ADSL filtering means comprise at least one low-pass filter and at least one high-pass filter connected to the wires of the line.

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According to the invention, the device is connected to the central telephone side, upstream of a test robot, the first operating mode corresponds to the normal operation of the line so as to ensure the analog and digital transmission, the second mode of operation is a mode corresponding to test measurements made on the line by the robot; the device disconnecting the filtering means of the line and thus making them transparent to the test robot, ie, on the one hand transparent to the signals emitted by the robot and, on the other hand, not modifying the measured values.

Other features and advantages of the invention will appear on reading the description given below and with reference to the appended drawings in which: FIG. 1 represents the block diagram of an ADSL filtering system placed on a side ADSL line telephone center ;
FIG. 2 represents the diagram of the isolation device according to the invention; - Figure 3 shows the detailed diagram of the embodiment of the device according to the invention;
Figs. 4A and 48 show the block diagram of charging and discharging capacity
Cr.

 The device according to the invention allows, according to the operating mode of an ADSL line, to isolate the ADSL filters while ensuring the continuity of the line.

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The device makes it possible, when the test robot is activated, to control the isolation of the LPF / HPF filters.

As can be seen in FIG. 2, the device comprises: an LPF / HPF isolation circuit IS: this circuit completely isolates the two filters so that the subscriber line regains its original characteristics.

a control circuit P which makes it possible to control the LPF / HPF isolator during measurements made by the test robot while being entirely transparent with respect to the latter.

The device according to the invention has the following advantages:
Total transparency to the tests and to the subscriber line. The voice band and the broadband services are not affected by the insertion of the device.

 In addition, the device consumes only when it is put into service to perform test measurements.

 The LPF / HPF isolator circuit IS comprises, as will be seen later, several work / rest contacts operated by a relay. These allow, during measurements of the test robot exclusively, to completely isolate the LPF and HPF filters while ensuring the continuity of the line.

 The HPF filter being isolated, it is assumed that the ADSL transmission is momentarily interrupted during measurements for a period of approximately a few tens of seconds (typically 25s). It is

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à noter que les mesures de test perturbent le système ADSL au point de désynchroniser les modems.

note that the test measurements disrupt the ADSL system to the point of desynchronizing the modems.

 The circuit P providing the control function controls the relay whose work / rest contacts constitute the LPF / HPF isolator. It includes a number of components and is fully transparent during the activation of the RT robot.

 The energy required to perform this operation is obtained from the discharge of a tank capacity, which is charged when the line is connected to the switch (53V) or to the measuring robot. Indeed, before the measurements are performed, the latter delivers a DC voltage of approximately 48V between two series of tests.

 When an insulation fault on a wire or between wires (loop test) is present on the line, the robot performs measurements of echometry, loop current and capacitance from the central office.

 As has been said on an ADSL link, the presence of low-pass filters LPF and high-pass HPF AC central side does not allow to perform certain tests (location of defects and capacity measurements).

 The proposed device thus makes it possible to circumvent this problem.

 The principle of the device, located on the central side, is to isolate the low pass and high pass filters from working / rest contacts whose relays are activated only when the test robot performs measurements.

 For information and in a general way, customer-side equipment (telephone, modem, filters ...)

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sont susceptibles de modifier les paramètres intrinsèques de la ligne (ligne seule), mais ne remettent nullement en cause la validité des outils de supervision de la ligne (robot de test).

are likely to modify the intrinsic parameters of the line (line only), but do not call into question the validity of the line supervision tools (test robot).

dépend soit du terminal raccordé, soit du module RC (20kQ//2. 2pif). Dans cette configuration, le robot détecte la présence d'un terminal. On a subscriber line that does not have ADSL equipment, we find ourselves in a similar situation to the extent that the value of the capacity

depends on either the connected terminal or the RC module (20kQ // 2, 2pif). In this configuration, the robot detects the presence of a terminal.

We will now explain in more detail the operation of the device DI with reference to the detailed diagram of Figure 3 and Figures 4A and 4B.

 In the proposed embodiment, the values of the components are given as an indication. Optimizations and adjustments remain of course possible without calling into question the principle of the invention described.

 The charging and discharging times are also given as an indication.

The IS isolator circuit of the LPF / HPF filters disconnects or reconnects the filters in the line as follows:
When the test robot is activated, that is to say during the execution of the measurements, the contacts repos 2, reIn and rel22 open and thus allow the disconnection of the low-pass and high-pass filters. At the same time, the contacts work rel23 and rel24 (derivation at points AB and CD) close and

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assurent de ce fait la transparence totale de la ligne.

thus ensure total transparency of the line.

In the absence of test measurements, the line presents the characteristics of an ADSL connection on the local network; ie the maintenance of voice band services (ringing, Class services ...) and broadband services
The control circuit P detects the change in the operating mode of the line.

This circuit P controls Reli and Rely relays, the power supply of these relies on the principle of a charge / discharge through the capacity Cr called tank capacity.

This operation is carried out in two phases: - a charging phase of the reservoir capacity Cr (FIG. 4A):
This phase is performed when the line is connected to the AC central office or the RT test robot (before the measurements are performed). The capacitance Cr then charges at a voltage Valin (typically 41V) via the transistor T1, the resistor R4 and the resistors of the coils Reli and Rel2; the transistor Tz being blocked with respect to the remote supply of the line (53V at the open output), the observed voltage drop (12V in this arrangement) is due to the voltage Vgs of the field effect transistor Tu. The load time of the device is approximately lmnl5s, which gives approximately a load time constant of the set Tcte Tps load = 13s.

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d'alimentation) et le transistor T2 devient alors passant, Tl étant alors bloqué. La capacité Cr se décharge alors au travers des relais Reli et Rel2 montés en série (le temps de décharge du dispositif est d'environ de 19s, ce qui donne approximativement une constante de temps de décharge du montage acte tps charge = 8,2s). a discharge phase of the reservoir capacity Cr (FIG. 4B):
As soon as the test robot measures, the DC voltage drops to OV (no voltage

power supply) and the transistor T2 then becomes on, Tl then being blocked. The Cr capacitance then discharges through the series-connected Reli and Rel2 relays (the discharge time of the device is approximately 19s, which gives approximately a time constant of discharge of the assembly act tps charge = 8.2s) .

During the execution of the measurements (approx. Batches), the robot also sends DC voltages of 48v. The rest contact relll by opening the supply loop of the two transistors T1 and T2 (Vgg = 0) in order to avoid a new charge / discharge of the capacitor Cr. It also makes it possible to guarantee the insulation resistance of the line (RA / B) -
In the exemplary embodiment, the duration of the discharge time of the Cr capacitance is two times greater than the time required to perform the test measurements. It is possible to envisage other values for the components: relays Reli and Rel2 (resistances of the coils); Cr capacitor to increase or reduce the discharge time.

 We will now detail the role of the various components by specifying the values of the preferred example given.

 The zener diodes:

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Les diodes zéner DZ, et DZ2 (Vseuil = 12V) servent à fixer les tensions de grille-source Vgs des 2 transistors à effet de champ T1 et T2 (référence choisi à titre d'exemple BS 250 et 2N 4191).

The zener diodes DZ and DZ2 (V threshold = 12V) are used to set the gate-source voltages Vgs of the two field effect transistors T1 and T2 (reference chosen as example BS 250 and 2N 4191).

Resistances R1 to R3:
They constitute the polarization bridge of zener diodes DZ, and DZ2. They also have a high resistance value (> 1 M #). as a result, power consumption is almost zero.

Capacities C1 and C2 (lnF):
They play a filtering role with respect to ring trains.

The resistance Rq:
It serves to limit the ringing current. The value of this resistance must be between a minimum value and a maximum value (value of the assembly, R4 = 4.7 ka) because a rather high value of this resistance would increase too much the load time of the capacity Cr.

Relays Rell and Rel2:
As has been described in the operation of the device, it is they who ensure the isolation of the filters of the different work / rest contacts. The selected relays (TX2 telecom series) have a nominal voltage of 24V and also have a high coil resistance (4.2kΩ). This makes it possible to increase the discharge time of the capacitor Cr.

The input diode bridge D1 to Dq:
It serves to polarize the entire control circuit P circuit ensuring the isolation of the filters during the mode

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opératoire mesures de test sur la ligne. Ainsi, il n'est pas nécessaire de connaître les polarités de la ligne pour raccorder celle-ci.

Operative test measurements on the line. Thus, it is not necessary to know the polarities of the line to connect it.

 The device that has just been described makes it possible to keep the existing tools and robots used by the operators as they are.

 The measurements and their interpretation remain intact for the qualification of the subscriber lines. The device only consumes during test measurement tests.

 Reference can be made to the attached table which illustrates different measurement results made by a test robot in the various configurations mentioned: cases 1 to 8.

Cases 1,2 and 3 are given as an indication and can serve as a reference. The first two correspond to an analogue line without ADSL equipment and connected either to a terminal or to an RC tag (2. 2 pF in series with 22 kΩ). The third case is that of an analog line with an ADSL modem (ATU-R card + filter) only on the user side for comparison (not shown). The differences observed mainly relate to capacitance measurements between Ca / b // wires (C a / T + C b / T).

Case 4 is an open line reference in the absence of ADSL equipment. In this configuration, a fault is actually found and located by the test robot.

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'Le cas 5 permet de constater qu'en l'absence du dispositif, les mesures de test sont complètement faussées : en particulier l'échométrie et les mesures de capacités. Le robot localise un défaut à 1 m (cela correspond en fait à la distance robot/filtre) et ne voit pas d'installation terminale.

Case 5 shows that in the absence of the device, the test measurements are completely distorted: in particular echometry and capacity measurements. The robot locates a fault at 1 m (this actually corresponds to the robot / filter distance) and does not see a terminal installation.

 * Case 6 makes it possible to demonstrate the interest of the device. We find the same measures as those corresponding to case 3 (no ATU-C).

 Case 7, device in the absence of ATU-C simply confirms its transparency with respect to the filter on the central side.

 * Case 8 also makes it possible to verify that the device does not alter the detection of the measured open output fault in case 4.

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<Tb>
<Tb>

Cases <SEP> 1 <SEP> 2 <SEP> 3 <SEP> 4 <SEP> 5 <SEP> 6 <SEP> 7 <SEP> 8
<tb> Config. <SEP> Without <SEP> Without <SEP> With <SEP> With <SEP> With
<tb> device <SEP> device <SEP> disposifis <SEP> device <SEP> device <SEP> device <SEP> device <SEP> device
<tb> Side <SEP> Unchanged <SEP> Unchanged <SEP> Unchanged <SEP> Unchanged <SEP> ATU-C <SEP> Device <SEP> Device <SEP> Device
<tb> Central <SEP> + <SEP> ATU-C <SEP> Without <SEP> ATU-C <SEP> + <SEP> ATU-C
<tb> Terminal <SEP> Module <SEP> RC <SEP> ATU-R <SEP> Output <SEP> ATU-R <SEP> ATU-R <SEP> ATU-R <SEP> Output
<tb> Side <SEP> (phone) <SEP> + <SEP> open <SEP> + <SEP> terminal <SEP> + <SEP> terminal <SEP> + <SEP> terminal <SEP> open
<tb> user <SEP> terminal
<tb> Default <SEP> m) <SEP> none <SEP> none <SEP> 1 <SEP> (4732m)
<tb> localized
<tb> Diagnosis <SEP> B. <SEP> A. <SEP> E * <SEP> B. <SEP> A. <SEP> E <SEP> B. <SEP> A. <SEP> E <SEP> Open <SEP> 2 <SEP> child <SEP> Open <SEP> 2 <SEP> child <SEP> BAE <SEP> BAE <SEP> open <SEP> 2 <SEP> child
<tb> Installation <SEP> Presence <SEP> Presence <SEP> Presence <SEP> PasdeNotPresence <SEP> Presence <SEP> Pas <SEP> d
<tb> n <SEP> Terminals <SEP> Tag <SEP> RC <SEP> Terminals <SEP> Setup <SEP> Setup <SEP> Terminals <SEP> Termination <SEP> Setup
<tb> terminal <SEP> on <SEP> on <SEP> terminal <SEP> terminal <SEP> on <SEP> terminal
<tb> R <SEP> a / b <SEP> 10 <SEP> M # <SEP> 10 <SEP> M # <SEP> 10 <SEP> M # <SEP> 10 <SEP> M # <SEP> 10 <SEP> M # <SEP> 10 <SEP> M # <SEP> 10 <SEP> M # <SEP> 10 <SEP> M #
<tb> R <SEP> a / T <SEP> 10 <SEP> M # <SEP> 10 <SEP> M # <SEP> 10 <SEP> M # <SEP> 10 <SEP> M # <SEP> 10 <SEP> M # <SEP> 10 <SEP> M # <SEP> 10 <SEP> M # <SEP> 10 <SEP> M #
<tb> R <SEP> b / T <SEP> 10 <SEP> M # <SEP> 10 <SEP> M # <SEP> 10 <SEP> M # <SEP> 10 <SEP> M # <SEP> 10 <SEP> M # <SEP> 10 <SEP> M # <SEP> 10 <SEP> M # <SEP> 10 <SEP> M #
<tb> R <SEP> a / bat <SEP> 10 <SEP> M # <SEP> 10 <SEP> M # <SEP> 10 <SEP> M # <SEP> 10 <SEP> M # <SEP> 10 <SEP> M # <SEP> 10 <SEP> M # <SEP> 10 <SEP> M # <SEP> 10 <SEP> M #
<tb> R <SEP> b / bat <SEP> 10 <SEP> M # <SEP> 10 <SEP> M # <SEP> 10 <SEP> M # <SEP> 10 <SEP> M # <SEP> 10 <SEP> M # <SEP> 10 <SEP> M # <SEP> 10 <SEP> M # <SEP> 10 <SEP> M #
<tb> C <SEP> a / T <SEP> 213 <SEP> nF <SEP> 213 <SEP> nF <SEP> 213 <SEP> nF <SEP> 213 <SEP> nF <SEP> 282 <SEP> n <SEP> 213 <SEP> nF <SEP> 213 <SEP> nF <SEP> 213 <SEP> nF
<tb> Cb / T <SEP> 213 <SEP> nF <SEP> 213 <SEP> nF <SEP> 213nF <SEP> 213nF <SEP> 264 <SEP> pF <SEP> 213 <SEP> nF <SEP> 213 <SEP> nF <SEP> 213 <SEP> nF
#### <SEP> nF <SEP> 766 <SEP> nF <SEP> 120 <SEP> n
<tb> C <SEP> pF <SEP> 872 <SEP> nF <SEP> 872 <SEP> nF <SEP> 227 <SEP> n
<tb> Length <SEP> 4.72 <SEP> km <SEP> 4. <SEP> 71 <SEP> km <SEP> 4.94 <SEP> km <SEP> 4.71 <SEP> km <SEP> 1 <SEP> m <SEP> 4. <SEP> 94 <SEP> km <SEP> 4.94 <SEP> km <SEP> 4.71 <SEP> km
<tb> echometric
<tb> Time <SEP> s <SEP> 54 <SEP> s <SEP> 56 <SEP> s <SEP> 54 <SEP> s <SEP> 0 <SEP> s <SEP> 56 <SEP> s <SEP > 56 s <SEP> 54 s
<tb> echometer <SEP>
<tb> Amplitude <SEP> 999 <SEP> 999 <SEP> 999 <SEP> 999 <SEP> 82 <SEP> 999 <SEP> 999 <SEP> 999
<tb> relative
<tb> Noise <SEP> -90.48 <SEP> -89. <SEP> 92 <SEP> dBm-91. <SEP> 48-90. <SEP> 22 <SEP> dBm <SEP> -90.45 <SEP> dBm <SEP> -91 <SEP> dBm <SEP> -91.16 <SEP> dBm <SEP> -89.94 <SEP> dBm
<tb> psopho-dBm <SEP> dBm
<tb> metric
<tb> potential <SEP> 0 <SEP> V <SEP> 0 <SEP> V <SEP> 0 <SEP> V <SEP> 0 <SEP> V <SEP> 0 <SEP> V <SEP> 0 <SEP > V <SEP> 0 <SEP> V <SEP> 0 <SEP> V
<tb> current <SEP> +/- <SEP> 1 <SEP> A <SEP> 0 <SEP> A <SEP> 0 +/- <SEP> 1 <SEP> A <SEP> 0 <SEP> A <SEP> 0 <SEP> A <SEP> +/- <SEP> 1A <SEP> +/- <SEP> 1A <SEP> 0 <SEP> A
<tb> * <SEP> B. <SEP> A. <SEP> E <SEP> (good <SEP> with <SEP> tests)
<Tb>

Claims (10)

 1. Isolator device for ADSL line transparent line that is to say that the voice band and broadband services are not affected by its insertion; this device comprises isolation means (IS), ADSL filtering means (LPF, HPF) arranged on the central telephone side (AC) and control means (P) of said isolation means (IS) for connecting or disconnecting the filtering means of the line respectively according to a first or a second operating mode of the line.  2. Insulator device according to claim 1, characterized in that it is connected to the central telephone side (AC) upstream of a test robot (RT), the first operating mode corresponding to the normal operation of the line so as to ensure the analog and digital transmission, the second operating mode being a mode of test measurements carried out on the line by the robot, the device (DI) disconnecting the filtering means of the line and thus making them transparent to the test robot it is to say on one hand transparent to the signals emitted by the robot and on the other hand not modifying the measured values.  3. Isolator device according to claim 1 or 2, characterized in that the control means (P) comprise: <Desc / Clms Page number 17>  two output terminals (a, b) respectively connected to the wires of the line upstream of the filtering means, detection means (Cr, Rell, Rel2) of the first and second operating mode of the line and control means ( T1, T2) for connection or disconnection of the filters, activated by these detection means.

 4. isolator device according to claim 3, characterized in that the detection means of the operating mode (because, Rell, Relu) comprise a circuit for charging and discharging a capacitor from the supply voltage of the line, providing a control voltage to the isolation means (IS); the device consuming only during the second operating mode, ie during the test measurements (charging and discharging of the capacitor Cr).  5. isolator device according to claim 4, characterized in that the circuit for charging and discharging a capacitor comprises said capacitor connected in series with at least one relay and a first and second transistor to provide said control voltage.  6. Isolator device according to claim 4 or 5, characterized in that the capacitor charging and discharging circuit comprises <Desc / Clms Page number 18>  respective polarization for the first and the second transistor.

 7. Isolator device according to any one of the preceding claims, characterized in that the isolation means comprise a plurality of contacts placed on the line son to connect or disconnect the filters while ensuring the continuity of said line.  8. Isolator device according to claims 7, characterized in that the first and second transistors allow according to their state to open and close the contacts placed on the line.  9. Isolator device according to any one of the preceding claims, characterized in that the connection means, disconnection of ADSL filtering means comprise a diode bridge for biasing said means to make them independent of the polarization of the line.  10. Isolator device according to any one of the preceding claims, characterized in that the ADSL filtering means comprise at least one low-pass filter and at least one high-pass filter connected to the son of the line.