DE874923C - Circuit arrangement for telephone systems with line selectors without control switches - Google Patents

Description

Siemens & Halske Aktiengesellschaft, Berlin and Munich line voters with control switch have the advantage that when setting up and disconnecting the connections required switching operations clearly and clearly without complicated dependencies of the individual circuits can be controlled. However, the control switch means one considerable effort. One therefore already has line selectors without control switches developed. It has succeeded even for line voters who manufacture allow high and low-order connections, so-called local long-distance line selectors, to use the switching means so versatile that you can use a relay set of six relay comes off. But it could not be avoided with such line voters that certain conditions to be imposed on good telephone traffic are not in sufficient measure have been observed. This is the case in well-known line selectors without control switches on the symmetry of the speech cores, which is in the interest of the lowest possible attenuation and the greatest possible crosstalk attenuation must be required is not sufficient Considered. In this known circuit, a of the two feed bridge relays of the line selector in series with resistors a voice wire kept locally excited, with a symmetry choke in this circuit lies. This increases the inductive resistance to speech currents in the supply circuit of the called, who without the choke as a result of being short-circuited via the local circuit Winding of the feed bridge relay strong would be reduced. For balancing there is a relay winding with a corresponding inductive on the other voice wire Resistance or another choke required.

The invention now wants to use a single throttle in the line selector get along, but still maintain the prescribed symmetry of the speaking circles.

You achieve this by having two windings connected in series a choke coil with a grounded center point symmetrically in bridge to the speech wires lie while one more winding of this choke. after reporting the called Subscriber in series with a winding of a feed bridge relay in one of the Speech wires free hold circuit is switched on.

Using the circuit of a local long-distance line selector shown in the figure OFLW an embodiment of the invention is described. In the ones listed below Circuits is the positive grounded pole with the plus sign, with the minus sign the negative pole of the official battery.

If the line selector is used when establishing a connection from the upstream connection device, e.g. B. a first group selector, occupied; the occupancy relay C responds via the incoming c-core. Relay C prepares the setting circuits and the test circuit in the usual way. The number current impulse series corresponding to the penultimate digit of the subscriber number,. Given by the upstream group selector as earth impulses on the a-wire. are picked up by the surge receiving relay A and transmitted via contact ia to the lifting magnet H of the line selector. The line selector arms are raised to the decade corresponding to the number of power surges. When the first current surge occurs, the short circuit for winding I of delay relay V is opened at contact 2a. Relay V responds: +, 13 P, i2 y, wave contact iiw, V I, ioc, Wi 5, -. Relay V holds during a series of impulses. When the series of current impulses is over, relay V drops out. When relay V drops out, relay U is switched on: +, head contact 14h, 15 v, 16 c, UI; Shaft contact 17 w, H, -. The solenoid H does not respond in this circuit. Relay U prepares the circuit for rotary magnet D. The current impulses of the last series of numbered current impulses, which now arrive, are in turn picked up by relay A and transmitted to the rotary magnet D : +, ia, 18u, igp, D, -. With the first current surge, the delay relay V responds again via its winding I, but this time after the opening of the shaft contact iiw via the closed contact 2ou. When the selector is turned for the first time, the shaft contacts flip over. Relay U is held after the opening of the wave connector 17 w via its winding II: +, 2i e, 22u, 23v, UH-. = .- The voter arms are turned to the desired subscriber connection line by the last stroke series in the selected decade: - After the series of current impulses, the relays V and U drop one after the other. During the release time of the relay U, the following test circuit is closed +, 21 c, 22 u, 24v, PI P II, c-arm of the line selector, - (in the selection). If the desired subscriber is busy, the test relay P cannot respond. The calling subscriber receives a busy signal from the line selector via winding IV of the choke coil Dr: +, busy alternating current, shaft contact 40w, 25a, DY IV, 26u, i2 y, 13A +. The busy alternating current is transmitted inductively from winding IV of choke Dr to windings I and II of the choke coil, which are symmetrically bridged to the speech cores, from which the busy signal arrives backwards via the speech cores to the calling subscriber.

If the desired participant is free, the test relay P responds. This switches through the two speech lines in the usual way, and blocks the occupied line against other occupancy; it also switches off the rotary magnet D, at the same time switching on the so-called first call during the release time of the relay U. For the latter switching process, the relay V, now serving as a call switch relay, is energized: +, throttle D 5, i. Call contact, 27u, V 1I, gy, Dr IIIx 7 c, 3 p, D, -. The rotary magnet D does not respond in this circuit. Relay V applies the ringing current source RQ to the a-wire via its contact 2gv. The ringing current is as follows: -, RQ, 29v, 30A a-arm, subscriber loop, b-arm, 31A 32v, YI, +. After relay U has dropped out, relay V, winding II, responds via contact 28u only every 5 seconds and transmits ringing current to the selected subscriber every 5 seconds. The circuit of relay V is as follows: throttle Ds (in the line selector signal set), 5-second contact, 28 u, V 1I, gy, Dr 11I, 7 c, 3 P, D, -. An alternating current source QF of about 450 Hz is superimposed on the 5-second circuit of the relay V via the capacitor C f for the purpose of transmitting the dial tone. This alternating current is inductively transmitted from winding III of choke Dr to the two windings I and II of choke Dr, which are in a bridge to the speech wires. From these, the alternating current of the dial tone reaches the calling subscriber backwards via the speech wires.

If the called subscriber answers by picking up his receiver, the feed bridge relay Y in the ringing circuit will respond via the subscriber loop that is now closed for direct current. Relay Y interrupts the circuit of the call interface relay V at contact gy. Relay V drops out. The feed bridge relay A can now also respond via the closed contact 33v and the subscriber loop in series with the relay Y. Relay Y switches on the one hand counting voltage to the b wire via contacts 3 A 4y, Dr II, and on the other hand via contacts 5 y, 6 ä, Dr I earth to the a wire. The earth on the a-wire serves as the subscriber registration identifier at the remote station for long-distance connections. After relay Y has responded, the following local holding circuit is closed for its winding III: +, Y III, 8y, Dr III, 7c, 3p, D, -. The rotary magnet again has fault current in this circuit. Relay Y remains in this way even after the call has ended if the called subscriber has hung up his receiver and interrupted the subscriber loop. The inductive resistance of the winding III of the choke Dy in the holding circuit of the winding III of the relay Y prevents a short circuit of this relay winding and avoids a reduction in the resistance of the feed bridge relay Y to speech currents. The consequence is that the symmetrical loading of the speech arteries is maintained. If the called subscriber hangs up his receiver at the end of a call, the feed bridge relay A drops out as a result of the interruption of the subscriber loop. Relay Y is held locally. By opening the contact 6a, the earth is separated from the a-wire and this gives the final sign in long-distance traffic to the long-distance place.

The ones that occur in the line selector when a remote connection is established Switching operations are of no importance for the invention and are therefore not discussed further described.

When the connection is released, initiated by hanging up the receiver at the calling station, the incoming c-wire is interrupted in the line selector LW. The occupancy relay C comes to waste. The blocking winding II of the test relay P is short-circuited via contacts 34c, 35a. Relay P comes to waste. After the relay P has dropped out, the following circuit for the rotary magnet D is closed: -E-, 14k, 15v, 36c, 37u, igp, D, -. The rotary magnet responds and turns the selector arm one step further. When the rotary magnet D responds, the winding II of the relay U is switched on via contact 38 d. Relay U responds and interrupts the circuit of the rotary magnet at contact 37u. The rotary magnet falls off. This also causes the relay U to drop out again. After the relay P has dropped out, the following circuit for the rotary magnet D is closed: -E-, 14k, 15v, 36c, 37't, ig p, D, -. The rotary magnet responds and turns the selector arm one step further. When the rotary magnet D responds, the winding II of the relay U is switched on via contact 38d. Relay U responds and interrupts the circuit of the rotary magnet at contact 372t. The rotary magnet falls off. This also causes the relay U to drop out again. After relay U has dropped out, the rotary magnet responds again and switches the switching arms forward by one more step. In this way, the selector is switched in a self-interrupting circuit step by step to the end of the contact bank, where the selector arms fall down and are then returned to the rest position by spring force. The voter is thus back in the idle position.

Claims (4)

PATENT CLAIMS: i. Circuit arrangement for telephone systems with line selectors without control switches, characterized in that two series-connected windings (Dr I, Dr 1I) of a choke coil with a grounded center point are symmetrically bridged to the voice wires, while another winding (Dr III) of this choke after the signaling of the called subscriber is switched on in series with a winding of a feed bridge relay (V III) in a holding circuit free of the speech wires. 2. Circuit arrangement according to claim i, characterized in that the winding the choke coil (Dr III) during the transmission of the ringing current for inductive transmission of signals (dial tone) on the speech path to the calling subscriber. 3. Circuit arrangement according to Claim i, characterized in that the feed bridge relay (Y) when reporting the called subscriber in the symmetry point of the bridge to the Speaking cores lying choke windings, separated by capacitors, to the two Speech wires each have different potentials (earth to a wire, voltage to b wire) for the transmission of switching processes (subscriber registration identifier, key) according to backwards via the connection path. 4. Circuit arrangement according to claim i to 3, characterized by their application to line selectors without control switch with a maximum of six relays.