DE1146130B - Circuit arrangement for telecommunication, in particular telephone systems with one or two subscriber stations per connection line - Google Patents

Description

Circuit arrangement for telecommunication, in particular telephone systems with one or two subscriber stations per connection line Addition to patent 1 112 132 The patent 1112132 relates to a circuit arrangement for telecommunication, in particular telephone systems with one or two subscriber stations per connection line, in which the telephone lines at the subscriber stations the rectifiers that guarantee secret traffic when two subscriber stations are connected to a connection line are connected and a threshold value diode is connected in series with the alarm clock, the curve of which is selected so that, taken in absolute terms, it is above the voltage drop across the diode in the supply state, but below the effective value the alternating ring voltage is present.

In the arrangement according to patent 1112132 and others known and proposed arrangements of this type are the alarm clocks of the subscriber stations between a wire and earth switched, or a wire must be connected to the subscriber station To ground when connecting two subscriber stations to one connection line to enable a separate call to both subscriber stations. In the grounding of the Alarm clock circuit is now to be seen as a disadvantage, as basically every one to be set up Participation place under in itself in most cases unnecessary effort with a Earth line would have to be provided in order to switch on a second subscriber station to the same connection line not at the previously set up subscriber station having to add an earth line, which would be unreasonable for the participant.

This disadvantage is eliminated in another proposed arrangement avoided that each subscriber station a resistor is connected in parallel, so that the rectifier assigned to a subscriber station to be called by a DC voltage connected to the speech wires in the idle state for the alternating ringing voltage are permeable. However, such an arrangement has the disadvantage that the parallel Resistance switched to the subscriber station, critical response or fault current conditions conditional for the call relay in the office. In addition, flows in the idle state of the subscriber station always a current over the subscriber line.

The object of the invention is, in an expedient further development of the object of patent 1112132 the disadvantages of the known and proposed arrangements to avoid. This is achieved by the fact that the alarm clock and the threshold value diode existing series connection switched between the speech wires of the subscriber line and that the alarm clock is switched and / or designed (e.g. as a direct current alarm clock or as a polarized alarm clock with one-sided rest position) that it can only be activated by power surges a certain direction can be influenced. With the invention it is without the effort an earth line to each subscriber station possible when two subscriber stations are connected to a common connection line each subscriber station independently of the other to call. To a connection line to which a subscriber station designed according to the invention is switched on, can be done without interfering with the circuit of this subscriber station and without any interruption of the traffic to this subscriber station at any time switch on the second subscriber station.

As voltage-dependent resistors with a kink characteristic, varistors are used and Zener diodes are conceivable. A direction-dependent characteristic of the curve such as in the subject of the main patent, however, is no longer required, since the direction of the current the effective ringing current can either be determined by the fact that it is used as an alternating current alarm clock trained alarm clock magnetic or mechanical, z. B. by a spring, so polarized is that it can only be influenced by current surges of a certain current direction, or in that with the as a direct current alarm clock or as a polarized alarm clock with unilateral rest position trained alarm clock at the subscriber station a rectifier is connected in series, which determines which current direction is effective. as The rectifier in series with the alarm clock can also be used to guarantee secret traffic Rectifiers are used when the alarm clock is on the subscriber side of this rectifier is arranged. The rectifier must then be rated for corresponding voltage values be.

Two exemplary embodiments of the invention are shown in the drawing. The two to the common connecting line VL and via this to the subscriber circuit TS connected subscriber stations T1 and T2 are designed differently; However each of the subscriber stations TI or T2 can also be configured with a similar one second subscriber station to be connected to the common line VL.

While at subscriber station T2 the alarm clock circuit and the spark extinguishing circuit for the pulse contact 3nsi2 emitting the number current surges are separated from each other, the capacitor K1, which is parallel to the number disk pulse contact nsi 1 of subscriber station T1 in the working state, also serves as a switching element supporting the operation of the alarm clock W1. Is the alarm clock W1 z. B. formed by using a mechanical spring as a polarized alarm clock, its operation as an alarm clock to be influenced by pulsating direct current can be improved by connecting the capacitor K1 in parallel if the alarm clock WI and the capacitor K1 have a frequency of the pulsating direct current or the alternating ringing current form a coordinated resonant circuit. The capacitor K1 can then be connected via a normally closed contact of the hook switch HU12 in parallel to the alarm clock W1 and via a normally open contact of the hook switch HU12 in parallel to the contact nsi 1 serving to deliver the number current surge series.

In the idle state, the starting voltage source WQ in the subscriber circuit TS is connected to the wires aa, or a, bb and b of the common line VL via the contacts it and 2t of the common isolating relay T. If one disregards the varistors V1 and V2 connected in series with the alarm clocks W1 and W2 of the stations, the following circuits exist in the idle state for the individual half-waves of the current that can be drawn from the AC voltage source WQ (la) WQ, IR1, 2t, bb, b, bl, G1, (Vl), HU121 K1 ' nsil a1, a, aa, 1t, G4, WQ. nsr 1 ' (1b) WQ, IR2, lt, aa, a, a2, G2, HU22, (V2), b2, b, bb, 2t, G3, WQ. There is thus the risk that the alarm clocks W1 and W2 of both stations T1 and T2 will be energized by the AC voltage source WQ. When the varistors V1 and V2 are switched on according to the invention in the circuits of the alarm clocks W1 and W2 , their influence by the AC voltage source WQ is prevented if, as is to be assumed here, the maximum value of the voltage of the wet voltage source, seen in absolute terms, is below the value at which the characteristic curve of the varistors shows a kink. Using the kink characteristic of the varistors, however, it is possible to operate the alarm clock independently of one another if the ringing voltage source is connected in series with differently polarized DC voltage sources between the wires of the telephone line.

The secret traffic between both participants on the one hand and the office on the other hand it is ensured by the rectifiers G 1 and G2 in the wires b 1 and a2. The rectifiers G1 and G2, as such, can for example be gold wire diodes Be used, must be of low capacity for this purpose. The rectifier of the participant to be effectively connected to the office is confirmed by the office The supply voltage connected to the speech wires is so biased that it is for both Half-waves of the speech alternating current is permeable, while the rectifier of the subscriber to be effectively disconnected from the common connection line is biased accordingly in the opposite direction and thereby both half-waves of the alternating speech current blocks: The rectifiers G1 and G2 assigned to the subscriber stations T1 and T2 and varistors V1 and Y2 can each be enclosed in pairs in a potting compound and in the station housings or; ' since these are very small components, can also be advantageously accommodated in the subscribers' junction boxes.

If one of the subscribers wishes to set up a call, he closes the hook changeover contact HUI or HU2 assigned to him by lifting his handset, thereby effectively activating the call relay assigned to him in the office. It should be assumed in the following that the participant; to which the station T2 is assigned, wishes to establish a connection and has lifted the receiver. The hook changeover contact HU2 is thus closed. The call relay R2 assigned to station T2 in the exchange responds via: (2) WQ, IR2,1 t, aa, a, a2, G2, I GU2, IIGU2, Wi2 M2, HU2, 3nsi2 , b2, b, bb, 2t, G3, WQ. 4 nsr 2 The relay R2 causes a call seeker to start and with its contact 5r2 short-circuits the winding I of the relay R1. At the contacts 6r2 and 7r2 the crossing of the speech wires and with the contact 8r2 a holding circuit for the relay R2 is prepared at the same time. The latter is closed when the call seeker left aas on the veins; bas and cas of the line occupied by the subscriber in station 2'2. In series with winding II of relay R2, the isolating relay T is effectively energized. The relay R1, whose winding II is in the same circuit, however, has fault current. After the relay T responds, the circuit (2) is interrupted at the contacts l t and 2 t and the wire aa is connected to the wire bas and the wire bb to the wire aas with the contacts 9 t and 10 t. The following supply circuit is closed for station T2: (3) earth (in call finder), bas, 6r2, 9t; aa, a, a2, G2, IGU2, IIGU2 M2 Wi2 , HU2, 4nsr2 ' 3nsi2 b2, b, ö bb, 10t, 7r2, aas, - (in the call finder) ._ The rectifier G2 is loaded in this circuit in the forward direction and so biased that it is permeable to both half-waves of the alternating speech current.

In this switching state, the subscriber of station T1 would pick up the receiver pick up, he can neither the conversation led by the subscriber of the station T2 hear by discussing his microphone Ml disturb his conversation, because the Rectifier G1 is biased in the blocking device so that it receives the incoming Blocks alternating speech currents and prevents the microphone from being fed.

It should be mentioned here that each of the subscriber stations shown for can be used as a single line subscriber station. Starting a individual subscriber station can also, as usual, in a via the subscriber loop running direct current circuit or with starting alternating voltage. In the last In this case, switchings are not required either in the office or at the location of the subscriber station, when a second subscriber station is connected to the connection line.

The subscriber stations T1 and T2 are called by the line selector LW , in which the ringing alternating voltage source RQ is connected in series with the office battery between the speech wires in such a way that the switching arm lwb of the line selector is connected to earth.

Depending on whether the subscriber station T1 or T2 is to be called, the line selector LW is set to the wires lalw, lblw and 1 elw or to the wires 2alw, 2blw and 2clw. The speech cores lalw, 2alw and lblw, 2blw are crossed with each other and connected to the line selector LW that when the subscriber station TI is to be called, earth potential at the core b of the connecting line VL and, when the subscriber station T2 is to be called, earth potential the wire a of the connecting line VL is located. According to the selected characteristic of the varistors V1 and V2, they prevent a direct current flow through the alarm clocks W1 and W2 during the ringing current pauses, and they are completely controlled into the transmission range during the half-wave of the ringing alternating voltage, which is added to the voltage of the office battery. Either the rectifiers G1 or G2 or the alarm clocks W1 or W2 themselves, which are polarized in such a way that when excited, they cannot strike in the direction in which the alarm clock of the other participant is supposed to ring, determine the direction in the alarm clock circuit. In the last case considered, the rectifiers G1 or G2 can then also be arranged on the part of the alarm clock circuits.

Claims (5)

PATENT CLAIMS: 1. Circuit arrangement for telecommunication, in particular telephone systems with one or two subscriber stations per connection line, in which the rectifier necessary for connecting two subscriber stations to a connection line is connected to the speech wires at the subscriber stations and a threshold value diode is connected in series with the alarm clock whose characteristic kink is chosen so that, taken in absolute terms, it is above the voltage dropping across the diode in the supply state, but below the effective value of the ringing alternating voltage, according to Patent 11 12 132, characterized in that the alarm clock (W1, W2) and the threshold value diode (V1 or V2) is connected in series between the speech wires of the subscriber line and that the alarm clock (W1, W2) is connected and / or designed (e.g. as a direct current alarm clock or as a polarized alarm clock with one-sided rest position), that he can only be rushed by a certain Rich processing can be influenced. 2. Circuit arrangement according to claim 1, characterized in that the alarm clock (W1) on the subscriber side of the secret traffic ensuring rectifier (G1) is arranged. 3. Circuit arrangement according to Claim 1 or 2, characterized in that a capacitor (K1) for the alarm clock (W1) is connected in parallel. 4. Circuit arrangement according to claim 3, characterized in that that the capacitor (K1) is parallel via a break contact of the hook switch (HU12) to the alarm clock (W1) and via a normally open contact of the hook switch (HU12) is connected to the contact (nsil) serving for the delivery of number current impulses. 5. Circuit arrangement according to one of the preceding claims, characterized in that that the alarm clock (W2) by a contact of the hook switch (HU22) from the subscriber line can be switched off. Documents considered: German Auslegeschrift No. 1077 264. Earlier patents considered: German Patent No. 1085 200.