FR2811153A1 - Telecommunication line protection current surge protection having identical circuit each wire series placed with limiting resistance parallel frequency selection capacitors. - Google Patents

Abstract

The current limiter has a module (1) connected to a telephone wire network and apparatus. The module has two identical circuits one for each wire (2). Each circuit has a resistance (R3) limiting the power in series on the wire in parallel with capacitors (C3,C4,C5). The capacitors select the frequency of signal on the line.

Description

Current monitor for telephone line The invention relates to

  telecommunications facilities. More specifically, the present invention relates to a module limiting the intensity

  maximum current that can flow on a telecommunication line

  tion to which a telecommunication device can be connected. Following the deregulation of the telecommunications market, notably in France, any equipment manufacturer currently has the possibility of

  put more or less any telecom terminal on the market

  munication. This concerns more particularly the telephones

  c. The traditional operator, in France until today France Telecom, no longer has the possibility of prohibiting its subscribers from connecting any type of sets, even if these sets do not meet the constraints

  techniques enacted by this operator. This can pose great problems.

operator problems.

  Indeed, for example in France, any telecommunication terminal

  tion was designed in such a way as to limit the current in the line to a va-

  their maximum, for example 60mA. The tension is usually

  48V, the electric power consumed by this telecom-

  munication could not exceed a certain maximum value. Thus, it was not necessary for the operator to ensure himself that the current supplied to any telecommunication device does not exceed this value to avoid any deterioration of equipment and any consumption

  excessive electricity. Indeed, the operator does not charge for a consumption

  electric mation on a telephone line but its time of use.

  If, during a test usually carried out by the operator, a consumption

  excess electricity was still detected, the operator could

  concluded that there was either a fault on this telephone line,

  either the user had connected a non-telecommunication device

  counterpart. In the latter case, the operator had the option of sanc-

  user, which he no longer has the right to do.

  The object of the present invention is in particular to limit the cost

  rant in a subscriber line to avoid dissipation of energy ex-

  among other things in a central office and to protect any operation

  rator of an excess consumption of electricity on a telecommunication line

  particular indication of its wired network.

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  This objective is achieved thanks to a current limiter module

  of a telephone line connecting a telecommunication device

  communication to a wired telephone network, said module being composed

  a double electrical circuit formed by two identical electrical circuits

  each assigned to a wire of said telephone line, each of the two circuits comprising a power resistor inserted in series

  on said corresponding wire to limit the current carried by it to

  that said telecommunication device and at least one component

  pacitive mounted in parallel on said resistor, for the selection of

  O10 frequency channels passing through said line.

  A limitation of the electric current on a telephone line of a wired network is obtained using a current limiter module,

  according to the present invention to be installed on this line. This module is

  characterized by its simplicity and robustness and its efficiency with regard to electrical disturbances, thus making it possible to substantially limit the costs for the operator. Being modularly designed, its installation

  on a telephone line will be all the more simplified. It will be

  geux for the operator to install it in his wired network, for example in a telephone exchange, more particularly in a well of

  cut of a distributor strip corresponding to the TV line

  targeted phone. Thus, the operator will be entirely in charge of his installation

and how it works.

  According to a particular embodiment, each circuit comprises

  at least a low value capacity, allowing more particular transit

  high frequencies, said capacity being placed in parallel

  on said resistance of the corresponding circuit.

  Preferably, each circuit comprises at least one electrical component for protecting said resistance from an overcurrent or an overvoltage. Other characteristics and advantages of the invention will appear.

  on reading the following description of a preferred embodiment

  tiel, given by way of illustration and not limitation, in the accompanying drawings in which: FIG. 1a is an electrical diagram of the module according to the present invention;

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  * Figure l b is an electrical diagram of an alternative module according to the present invention; * Figure 2 is a side view of an embodiment of the module according to the present invention; * Figure 3 is a top view of the embodiment of Figure 2

  of the module according to the present invention.

  In FIG. 1a and 1b, an electrical diagram of the module 1 electric current limiter according to the present invention is shown. This circuit is double and intended to be connected identically to both lo of the two wires 2 of a telecommunication line to be protected, each of two circuits having an input 2e and an output 2s on each of the two wires 2 of line. This double circuit is intended to maintain a symmetry of the access impedances of each wire with respect to the earth so that the longitudinal disturbances present on the subscriber line are not converted into transverse voltage which would be superimposed on the differential signal. normal transiting on the telephone line. This limiter module

  of electric current intended for a telecommunication line at the-

  which is connected to a telecommunication terminal such as a telephone or fax machine, is preferably installed at

level of a telephone exchange.

  The electrical circuit provided by wire 2 includes a resistor R3 placed

  created in series on this wire 2. This resistance, for example of a typical value

  that of 2200, will thus make it possible to limit both the electric power consumed to supply the subscriber line and the power dissipated in the subscriber equipment of the central office. For a voltage value of 48V, the maximum tolerated current must not exceed 60mA. This limit value allows on the one hand to avoid over-consumption

  of electricity that the operator cannot charge, and especially on the other hand

  ter an excessive dissipation of power at the level of the access cards of subscribers of the telephone exchange which can lead to a deterioration of equipment. A first capacitive branch of high value is provided in parallel on this resistor R3. Being particularly transparent at low frequencies between 300Hz and 3400Hz, it aims to allow the passage on wire 2 of corresponding frequency signals

  typically out of the way. In the embodiment shown in the figure

  gure la, this capacitive branch has two capacitors C4, C5

2811 1 53

  polarized, oriented head to tail with respect to each other, of typical value which may be about ten pF for a voltage of the order of 35V. These capacitors C4, C5 can advantageously be electrolytic capacitors, thus making it possible to have high value capacities while requiring little volume. In the variant of FIG. 1 b, this capacitive branch comprises two non-polarized capacitors C4 ′, C5 ′, made of ceramic, mounted in parallel, In addition to this, each double circuit contains a capacity C3

  of low value, also placed in parallel with resistor R3.

  This latter capacity C3, for example of 0.1 FF for a voltage of 50V, is more particularly transparent at high frequencies between 10 kHz and 100 MHz, thus allowing these frequencies to pass with a very reduced impedance. This will allow signals containing data to pass through on wire 2, for example

  coming from an ADSL transmission (Asymmetrc Digital Subscriber Loop).

  On the other hand, this will avoid degrading the performance of the whole

  subscriber equipment - current limiter from the point of view of symmetry

  sort, necessary to decrease the conversion rate of long-term disturbances

  gitudinal high frequencies induced on lines in trans-

  and thus improve the quality of telecommunications.

  Finally, each circuit also contains an electrical component intended to protect the resistance R3 from an overcurrent or a

  overvoltage, a relatively common phenomenon on a telephone line.

  This electrical component consists, in the embodiment of FIG. 1 a,

  a pair of power clipping diodes D3, D4 placed in parallel

  lele on the capacitors C4, C5, and on the resistance R3 ensuring in addition

  that the correct polarity is established across these capacitors.

  In the variant of FIG. 1 b, these are two bidireclion zener diodes-

nelles D3 ', D4' (transil diodes).

  Figures 2 and 3 show a side view and top view respectively of the module 1 of Figure lb. These figures show the modular embodiment of the current limiter according to the invention. The module 1 is formed on an elongated dielectric substrate 4, which carries on each face one of the two circuits of the double electric circuit, one per wire 2 of the

  telephone line, and two conductive tracks constituting one of the

  2nd and one of the 2s outputs connecting the double circuit to the Il-

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  two-wire telephone gene. These tracks extend over part of the length

  substrate, between the double electrical circuit and substantially one

  of the ends of the substrate. Thus, this module 1, intended for a tele-

  phone, is easily pluggable, for example, in a cut-out well of a distributor strip of a telephone exchange to which this line is connected. Nothing prevents, however, from considering installing this module at another location along this telecommunications line, for example directly in a telephone socket at the user's home.

  Module 1 also includes a housing or molding of

  tection, not shown, which covers and protects the double electrical circuit

corn.

  In these figures 2 and 3, the two corresponding tracks are recognizable.

  laying on inputs 2e and outputs 2s of wires 2 of the telephone line. Resistor R3 is connected to track 2e. Then follow in parallel the

  capacitor C5, diode D3, capacitor C4 and diode D4. Final-

  ment, the capacity C3 is placed just upstream from the exit track 2s.

  The two faces of module 1 are identical.

  A current limiter module according to the present invention is

  thus very simple in design. In addition, its modular side makes its ins-

  tallation. very easy to protect on a telephone line.

Claims (8)

claims:   1) Module (1) electric current limiter of a telephone line   cording a telecommunication device to a wired telephone network, said module (1) being composed of a double electrical circuit formed by two identical circuits and each assigned to a wire (2) of said telephone line, each of the two circuits comprising a resistor (R3) of power inserted in series on said corresponding wire (2) to limit the current carried by it to said telecommunication device and at least one capacitive component mounted (C3, C4, Cs) in parallel on said resistor, for the selection of frequency signals passing on said line.   2) Module (1) according to claim 1, characterized in that said resistance   tance (R3) limits the current on said wire (2) corresponding to a maximum value of mA. 3) Module (1) according to claim 1, characterized in that each circuit   has a high value capacitive branch, allowing more specific transit   rement of low frequencies, mounted in parallel with respect to said resistor (R3) of the corresponding circuit.   4) Module (1) according to claim 3, characterized in that said branch   high value capacitive has a pair of capacitors (C4, C5; C'4, C'5).   5) Module (1) according to claim 1, characterized in that each circuit   contains at least one capacity (C3) of low value allowing more partial transit   especially high frequencies, said capacity being placed in parallel on at   said resistance of the corresponding circuit.   6) Module (1) according to claim 1, characterized in that each circuit comprises at least one electrical component (D3, D4; D'3, D'4) of protection   said resistance of an overcurrent or an overvoltage.   7) Module (1) according to claim 6, characterized in that it comprises a   pair of diodes (D3, D4) for protecting said resistor.   8) Module (1) according to claim 4, characterized in that it comprises a pair of diodes for protecting said resistance of each circuit, said pair of diodes being mounted so that an adequate polarity is applied to said capacitors ( C4, C5) of said circuit, said capacitors being polarized capacitors. 9) Module (1) according to claim 1, characterized in that said module (1) is pluggable into a cut-out well of a connected connection strip to said telephone line.   ) Module (1) according to claim 1, characterized in that it is plugged in   ble in a telephone socket intended for said telecommunication device.   11) Module (1) according to one of claims 9 and 1 O, characterized in that   that it comprises a dielectric substrate (4) carrying on each of its faces a   one of the two circuits of the double electrical circuit, formed on a terminated part   nale of the substrate, and on the other hand two conductive input and output tracks (2e,   2s) connecting the double electrical circuit to said line.