DE2610453C2 - Circuit arrangement for controlling a charge meter - Google Patents

Description

The present invention relates to a circuit arrangement for controlling a charge meter in telecommunications switching systems, in particular in telephone networks, with the preamble of the claim listed features.

Clock pulses are used in the exchange to determine and record telephone charges generated during the call in continuous sequence on a charge counter of the calling party in the exchange and, if necessary, on a subscriber-specific fee meter or - Avoid being transmitted. The number of clock pulses sent out in a unit of time depends on the distance between the two participants. There are telephone networks with tax pulse counting known in which as the beginning of an established telephone call is a pulse train from the telephone exchange The number of pulses depends on the distance between the two telephone subscribers depends. In such a telephone network, the telephone conversation will arrive before the whole The impulse sequence ended by hanging up the receiver, then the information on the official billing meter is correct with the details of the individual subscriber, fed from the telephone loop without a backup battery The meter does not match because the latter has already been switched off, while the office-side Charge counter still registers and displays the remaining pulses of the transmitted pulse train.

The present invention has for its object to eliminate this disadvantage and a circuit arrangement that is only fed from the telephone loop and is independent of the polarity of the loop to control a subscriber-specific fee reporter to create.

The object set is according to the invention by cited in the characterizing part of the claim Features solved.

An exemplary embodiment of the circuit arrangement according to the invention is explained in more detail with reference to the drawing described. It shows

F i g. 1 is a block diagram of a circuit arrangement,

Fig. 2 is a circuit diagram of a circuit for short-circuiting of the fork contact and

F i g. 3 and 4 signal diagrams.

In FIG. 1, the office-side terminals of the subscriber lines a, b are denoted by au b \ and the subscriber-side terminals for connecting a subscriber _{telephone set are denoted by a 2} , bi . A blocking filter 1 is located in the subscriber lines a, b, which the from the

central incoming impulses not to the

Vote # 2. ^ can get. A demodulator 2 in

c in a bandpass filter is connected to the terminals ai, b \

hands. In subscriber line b there is one

escha'tung 3 provided, which is used to feed the

e ^ Utilization arrangement through the telephone loop

energy is used. The demodulator 2 eliminated

"° ^m T-ßerwelle to the terminals a ,, L ₁ from the

α t renlralo incoming pulses A so that on

λ ί output a signal B appears, which the

uiHkurve of the momentum corresponds to what allows this

• Treat 11ß as a logical signal. The

• I B is fed to a control circuit 4 of a counter 8 S'S "?

in monostable tilting circle 5, from a second, ₅

stable tilting circle 6 and from an output circle

The first monostable tilting circuit 5 protects the

r counter against parasitic pulses with a

η r which is shorter than a predetermined duration of

R40 ms The output signal C of the first monostable

iTnnkreises 5 feeds the second monostable

v "w-cis 6 which for the formation of an impulse

nter duration and that of the output circuit

7 d counter 8 acted upon by a signal D. the

Lontrkreis 4 of the counter 8 is connected to the feed switch

^S * rhiinden

n / Sat! B of the demodulator 2 is fed at the same time • f control circuit 9, which consists of two «»! Äa Sen circuits, of which the ^P ί S consists of a monostable trigger circuit 10 and J ₀ p-mem nSgcschalteten inverting monostable ^ Γη KiDokre s 11 and the second circle is formed by η further monostable tilting circle 12. S "10 forms after the falling flank of the subscriber telephone device short-circuits if the signal / has the logical value 1.

The feed circuit 3 is provided with a diode bridge rectifier 17, one diagonal of which is connected in the subscriber line and in the other diagonal of which there is a diode D and a capacitor Q , the positive terminal of the diode Di being connected to the NOR via the voltage divider 14. Gate 13 and the negative terminal on the one hand to the capacitor G and on the other hand to the control circuit 4 of the counter 8 is connected. The feed circuit 3 also supplies the monostable trigger circuits 10, 11 and 12 as well as the NOR gate 13 and the Kbpstufe 15 with current. The diode Di serves to maintain the voltage of the capacitor Q and prevents the voltage on the terminals of the diode bridge rectifier 17 from being maintained when the loop current flow is interrupted, for the purpose of forming the logical signal // which represents the loop current. The capacitor C1 has sufficient capacity to ensure the supply for a brief moment in which «has the value zero. ie / wipe the moment the listener is dropped and the moment in which the subscriber loop is closed by the circuit 16. , ^ ·,. ι ·

The circuit 16 for short-circuiting the Tcilnchmcrleitungcn a. b and thereby the fork contact of the telephone set connected to terminals U ₂ , O ₂ is shown in FIG. 2 shown. This connected to the economy circuit 3 via a resistor R and connected to the bistable multivibrator 15. Kre.s 16 consists of an oscillator 18 mi, a transistor T ₁ . Widcrsiaoden R ₃ , A ₄ . a capacitor Cj and cmc η transformer 19. The oscillator 18 are one of one

the pulse gap of a preceding taxi pulse, mpulsW and smaller than d, e gap between two,

, _{ical value} ,, _S o flows ^, _negative terminal of the

inverting monostable K.ppkr

Output of the monostable K _iPP circuit 12 are at two, the

3 and the diode bridge _{equal Μοη lg with}

ST from a to the _{Speiseschajtung aÄ} , teten Sp ₌ ngste ,, he ^^ ^

/ " F + H + G, which is fed to the set input 5 of a bistable multivibrator belonging to the control circuit 9, the reset input R of which is fed with the signal F of the monostable multivibrator 11.

pp ^^^^ _effectiweiie ^ _{1 H} üf « _v0 ^ a.Sramming ^g of F i, 3 and 4, two situations are explained.

p _a || _a ) The listener becomes the participant

during the pulse train preceding the taxi pulses

fs rsis £

Signal G falls to zero during the falling edge of signal B , ie when signal F still has the value zero. The signals F, G and H have the value zero, so that the signal / and the signal J assume the logic value 1. The circuit 16 is controlled by the signal / and short-circuits the fork contact of the telephone device. The telephone loop is thereby closed and the loop current is restored, which enables the counter 8 to count the pulses up to the end of the pulse train. The signal J remains at the value 1 until the moment in which the signal F assumes the value 1 again, ie when the time span between two successive pulses is greater than the time constant of the monostable trigger circuit 11, which corresponds to the end of the pulse train.

Case b) The listener will after the end
of the pulse train

This case with the switch-off point K is shown in the diagram in FIG. 4 shown. After 350 ms after the arrival of the last pulse, the Fdcn signal assumes a logic value of 1. The signals F, G and H no longer have the value zero at the same time, so that the signals / and / remain at zero. The circuit 16 is not activated and the telephone loop 5 remains open. No further pulse can then be counted.

The charge meter with the circuit arrangement according to the invention counts the pulses properly also in telephony networks with taxi pulse counting, in

ίο which one of the Distance of the two participants corresponding pulse train is sent out, even if the listener again during this "identifying" pulse train has been launched. The circuit arrangement only has static components, their energy consumption is very small, so that the whole sound arrangement can be fed from the telephone loop. the previous backup battery is not applicable. The circuit arrangement is polarity-independent and thanks to the non-galvanic, The coupling realized by the transformer 19 is resistant to high voltages.

For this purpose 3 sheets of drawings

Claims (8)

Patent claims: 1. Circuit arrangement for controlling a charge meter in Fernmel'devermiulungsanlagen, in particular in telephone systems, with a feed circuit switched in one of the subscriber lines for feeding the circuit arrangement from the telephone loop, with a blocking filter and a demodulator intended to remove the carrier wave of the tax pulse, which is sent to the subscriber lines are switched on, characterized in that the output of the demodulator (2) on the one hand with a control circuit (4) serving to control a counter (8) of the charge meter and fed by the feed circuit (3) and on the other hand with an Aiisteuerschaltiing equipped with logic elements (9 ), the output of which is connected to a circle (16) flying between the subscriber lines (a, flying circle) for short-circuiting the same when the loop current disappears during a pulse sequence preceding the taxi pulses. 2. Circuit arrangement according to claim 1, characterized in that the control circuit (9) consists of two parallel-connected circuits, of which the first circuit consists of; a monostable trigger circuit (10) and a downstream inverting monostable trigger circuit (11) and the second circuit represents a further monostable trigger circuit (ll2), the output of which is connected to a first input of a NOR gate (13), the second input of which is connected to the inverting monostable trigger circuit (1:11) is connected and its third input is connected to the feed circuit (3), the output of the NOR gate (13) being connected to the set input (S) of a bistable trigger circuit (15), whose reset input (R) is connected to the output of the inverting monostable breakover circuit (11). 3. Circuit arrangement according to claim 2, characterized in that in the supply line between the Supply circuit (3) and the third input of the NOR gate (13) a voltage divider (14) is provided is. 4. Circuit arrangement according to claim 1, characterized in that the circuit (16) for short-circuiting the subscriber lines (a, b) consists of an oscillator (18) with an upstream switch (K ₂ , T ₂ ) and a smoothing capacitor (C ₂ ) which feeds a rectifier (20) via a: n transformer (19), the output of which is fed via an amplifier (21) to a diagonal of a diode bridge rectifier; (22) is connected, the other diagonal between the subscriber lines (a, flies. 5. Circuit arrangement according to claim 1 and 2, characterized in that the feed circuit (3) has a Diodenbrückcngleichrichter (17), one diagonal of which lies in one of the subscriber lines (a, b) and on the other diagonal of which a capacitor (Ci) and one Diode (Di) are switched on, one terminal of the diode (Di) being connected to the NOR gate (13) and the other terminal on the one hand to the control circuit (4) of the counter (8) and on the other hand to the capacitor (Ci). 6. Circuit arrangement according to claim!, Characterized characterized in that the control circuit (4) of the counter (8) consists of two monostable K'ippkreise (5,6) connected in series, one of which the first breakover circuit (5) protects the charge indicator from parasitic impulses and the other The tilting circuit (6) is used to form a pulse of constant duration and the counter (8) has a Output circuit (7) controls, 7. Circuit arrangement according to claim 1, characterized in that the demodulator (2) is a Band pass filter is. 8. Circuit arrangement according to claim 1, characterized characterized in that the entire circuit arrangement is equipped with static components.