US1845571A - Transmission of selector impulses or the like over duplexed lines - Google Patents

Description

5, 1932. R. TRECHCINSKI 1,845,571

TRANSMISSION OF SELECTOR IMPULSES OR THE LIKE OVER DUPLEXED mums- Filed Aug. 19, 1950 2 Sheets-Sheet l R. drech BULLS/Q1 Feb. 16, 1932. R; TRECHCINSKI 1,845,571

TRANSMISSION OF SELECTOR IMPULSES OR THE LIKE OVER DUPLEXED LINES Filed Aug. 19, 1930 2 Sheets-Sheet 2 R Urea c; WS/

Patented Feb. 16, 1932 UNITED STATES :PATENT OFFICE,

ROMAN TRECHGINSKI, OF WARSAW, POLAND, ASSIG-NOB TO TELEFONAKTIEBOLAG-ET L. M. ERICS SON, 0F STOCKHOLM, SWEDEN, A COMPANY OF SWEDEN TRANSMISSION OF SELECTOR IMPULSES OR THE LIKE OVER DUPLEXED LINES 7 Application filed August 19, 1930, Serial No. 476,378, and in Sweden August 20, 1929.

The transmission of selector impulses over duplexed lines is connected with certain diliiculties which, to a certain extent, are due to the fact that the duplexed natural lines and, in certain cases, also the duplex line formed may not be advantageously arranged in metallic connection with theappertaining impulse sending and impulse: receiving devices whereby thus the tra'nsmission'of direct current impulses over-the lines is made impossible. Instead of sending rectified impulses separated by current interruptions over the line, an eflicient and reliable impulse sending over such lines may, however, be brought about according to the invention by adapting the impulse sender, to bring about reversals of the current direction in a local impulse circuit which is inductively connected with the lines, by way of example, by means of an appertaining duplexing coil. The current in the local impulse circuit will evidently be subjected to variations equal to twice the amplitude of the current and, by the inductive connection of the impulse circuit to the line, induction current impulses will be sent over the line of corresponding double intensity which actuate a polarized impulse relay on the receiving side.

The invention will be more closely described with reference to the accompanying drawings on which Figure 1 diagrammatically illustrates the idea of the invention. Figure 2 shows some current diagrams and Figures 3 and 4 show two embodiments of the invention.

In Figure 1 the reference character 1 denotes the impulse contact in an impulse sender, by Way of example a finger disc or a dial. The impulse contact 1 is series connected with the winding 2 of a contact relay, the contact set of which is arranged as a commutator or pole reversing device in a local intermediate circuit including the primary winding of a transformer T, the secondary winding of which is connected to the telephone line L. Said intermediate circuit is, in similarity with the impulse circuit proper, open when there is no conversation going on. When the intermediate circuit is closed, the plus pole of the appertaining impulse battery is connected to the one terminal of the transformer T over a choke coil 3-and a normally closed contact 4 in the contact set of relay 2 whereas the minus pole is connected to the opposite terminal over a choke coil 3 and a normally closed contact 4 of the relay. The primary winding of the transformer is then gassed by When current in the directioniof the arrow the relay 2 is energized the contacts 4, 4 are opened and the battery poles are instead ,con

ing, by way of example, when the subscriber lifts his microtelephone, the impulse intermediate circuit, including the primary windmg of the transformer T, is closed. At the moment in question, which is designated t at b in Figure 2, the current in the local circuit rises in positive direct-ion and reachesafter a certain short period of time its full value i The closing ofthe impulse circuit proper, including the relay winding 2, may, if desired, also be causedby the lifting of the subscribers micr-otelephone but is somewhat delayed by a suitable mechanical or electromagnetical damping device and takes this place first at the moment "(5 at a in Figure 2, when the current in the primary circuit of the transqformer already has reached its full-value. In

the current closing in the intermediate circuit, a current impulse 2" at 0 in Figure 2, has been sent over the line which impulse may serve to set the polarized relay inits starting position in case the relay does not already take up said position.

When the relay 2 at the time is energized,the current in the impulse intermediate circuit is reversed by means of the contact set in above described manner and is thus subjected to a variation equal to 21 On account of the current reversal in the primary winding of the transformer, a second impulse i of twice the amplitude of the first impulse is sent over the line. Said impulse may serve to initiate the selecting operation, by Way of example, by that the polarized relay, upon its shifting, actuates a pre-selector or a finder. When the subscriber thereupon actuates his impulse sender and thereby brings about repeated current interruptions and closings i of short durations at a contact 1, a series of corresponding current reversals, designated i at b in Figure 2, are thereby caused in the intermediate circuit and a corresponding series of alternately positive and negative current impulses 2' at c in Figure 2, are sent over the line which impulses shift the armature of the polarized relay 6 between its two positions. The polarized impulse relay sends then in turn corresponding selector impulses.

When the subscriber at the end of the conversation hooks up his microtelephone both the impulse circuit proper and the impulse intermediate circuit are interrupted simultaneously at the time 3 a final impulse 2' being then sent over the line, by means of which impulse the polarized relay, if required, is restored to its starting position.

In the embodiment according to Figure 8 the two telephone lines L L are duplexed in ordinary manner by means of duplexing transformers T T T T so as to form a duplex line. Each one of the three lines is r on the sendingside provided with an impulse sending device A A and A respectively of the kind described above and comprising a current reversing relay 2. In the two natural lines L L the two appertaining duplexing coils T T are used also for the connection of the impulse intermediate circuit to the line and serve thus, in addition to their ordinary purpose, to replace the transformer T in Figure 1. the duplex line is connected to the line over a transformer T On the receiving side an impulse receiving device B B or 13 respectively is connected to each one of the lines. Said device comprises a polarized relay 6. The connection between the two natural lines L L and the appertaining impulse receivers B B respectively is mediated by the corresponding duplexing transformers T T whereas the impulse receiver B for the duplex line is connected over a special transformer T The three impulse receivers B B B are on their opposite side connected to a common selector device C in the exchange.

The embodiment according to Figure 4 is differentiated from] that in Figure 3 only thereby that the impulse sender A and the impulse receiver B of the duplex line are directly associated with the line.v

I claim 1. A switching arrangement for the transmission of current impulses over phantomed lines, comprising an impulse circuit, an impulse sender controlling said circuit, a relay connected to said circuit, a direct current source, a transformer connecting said direct current source with the line, and means under the control of said relay for reversing the cur rent supplied to the transformer, a polarizing relay being provided for the reception of the induction current impulses of alternating direction sent through the transformer upon actuation of the impulse sender.

2. A switching arrangement as claimed in claim 1, in which said direct current source is connected through inductances or resistances to its circuit including a contact set of said relay adapted to operate as a pole reversing device and a primary winding of the transformer.

8. A switching arrangement as claimed in claim 1, in which is provided a pole reversing device, the duplexing coils on the sending side being adapted to transfer inductively to a main line the current impulses reversed by the pole reversing device.

4. A switching arrangement as claimed in claim 1, inwhich the duplexing coils on the receiving side are adapted to transfer the impulses to the appertaining polarized receiving relays.

In testimony whereof I affix my signature.

ROMAN TRECHCINSKI.

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