US2137408A - Telephone system - Google Patents

Description

Nov. 22, 1938. F. LILL TELEPHONE SYSTEM Filed Dec. 2. 1935 INVENTOR. FRIEDRICH LILL Tim P i A TTORNE Y. I

Patented Nov. 22, 1938 PATENT OFFICE TELEPHONE SYSTEM Friedrich Lill, Vienna, Austria, assignor to Siemens & Halske Aktiengesellschaft, Wernerwerk, Siemensstadt, near Berlin, Germany Application December 2, 1935, Serial No. 52,452 In Austria December 3,1934

, Claims. (01. 179-30) In telephone systems in which alternating current'impulses are transmitted over the connectingline care has to be taken that the transmiss-ion of alternating. current, which passes over the 5 line in both directions during the call and brings about switching operations atboth ends of the connecting line, takesiplace systematically so'that the alternating current impulses do not proceed simultaneously thereby preventing important switching operations from taking place.

This systematic operation cannot be observed, however, when-telephone systems having subscribers provided with magneto ringing are involved in which unforeseen alternating currents may be transmitted at all stages of the call.

,The invention resides in that, in systems in which alternating current impulses are sent out from, anexchange and which have subscribers stations provided with magneto operation, the transmission of individual alternating current impulses seizing and releasing impulses) efiected by the exchange, which are ofimportance for the call and which control connecting devices, is delayedin the event of the subscriber transmitting 25 alternating current either simultaneously with or partly before the impulse transmission, during the time thus occupiedby the magneto current.

A further characteristic of the invention resides in that in the exchange devices, only alternating current impulses sent out by the exchanges in.- volved are operative, dependent on their duration and sequence, and that the duration and sequence of the alternating current impulses passing over the connecting line are supervised in the connecting devices by means of relay combinations.

The drawing represents an embodiment of the invention. A system is shown for communicating from subscribers connected to a party line who are provided with local battery and magneto stations in which all calls including internal calls are set up in a semi-automatic manner by way desires. a connection ;with another subscriber of the same local exchange or group. Since the establishment of all calls is only semi-automatic he must call up 'the communicating or main ex- 55' change over the connecting trunk line.

It will be assumed that one of the subscribers The call is set up by-the transmission of alternating current from the magneto of the calling subscriber whereupon the speaking leads of the subscriber are switched through on to the leads a and b in the ,relayrepeating device which is not shown since it is not essential ,forunderstanding the invention The alternating current sent out by the subscriber energizes the alternating current relay W3 whichswitches the line through at contacts 31w3 whereuponthe drop FK associated with the cut-ofi jack Klz is also operated over the connecting line'VLtgwhich terminates in repeating coils UI and U2. The operatorof the connecting exchange is thereby informed of the existence of the call and inquires by plugging into the jack. t

' The drop FK isidisconnected by the plug and the jack contacts l3kli operated. The following switching operations take place: Relay D energizes over earth, l3klz', Hwl, Illal, Wil, D, and battery, whereupon relay E energizes over earth, 38d and Wi2, and the relay F over earth, 32c, W14, F, and Wi3. The adjustment of relays D, E, and F over resistances Wil, WiZ, and Wz'4 is such that these relays, which are moreoverprovided with a copper sleeve over the core, energize relatively slowly. From the operation of the'jack contacts l3klz' until the energizing of relay F, relay RI remains energized. It energizes in the circuit: earth, l3kli, Hwl, lflal, 8d, 1112,61, RI, and bat tery, and locks up, after the opening of contact 8d, at contact am until it is ,disconneced by contact 61. Over contacts 211'! and 2811 an alternating current seizingimpulse is applied to the connecting line throughout the time during which relays D,E, and F are energized. By means of this impulse relay W2 is energized over the line. Contact 541,0 2 of relay W2 causes relay G to energize over contact 53k. This relay energizes relay H by means of contact 51g and the latter relay brings up relay K over contact-56h. Contact 5370 disconnects relay G again and locks up relay K until contact 54102 opens. Contact 38k disconnects the speaking line. Relays G and subsequently H make a delayed release. When the seizing impulse comes to an end relay H still re-' mains energized after relay W2 releases since the seizing impulse only lasts during the energizing period of three relays (D, E and F), so that now relay B energizes over earth, 44102, 4519(2), 46h, Wz'5; B, and battery. Relay B is constructed as a two-stage relayand on being operated over Wi5 only operates contact 4'lb(l). The contacts operated when the relay is fully energized bear the index (2) "7, After the release of relay Hrelay B establishes a locking circuit, earth, 48rt, 4'Ib( I) in which it energizes fully on account of Wi5 having been short circuited at 46h. The speaking line is switched through by means of contact 3617(2). Contact 42b(2) seizes the relay repeater device over the c-lead in a corresponding manner.

If the subscriber transmits alternating current by operating his magneto while the plug is inserted in the jack, the transmission of the seizing impulse does not take place until relay WI deenergizes again, since this relay energizes and opens contact IIwI. Relays D, etc. then energize over contacts I3kli, IIwI, etc. whereupon relay RI is energized transitorily, etc. as has already been described.

After the enquiry on the part of the operator the latter dials impulses over the line, since the subscriber desires a connection with the subscriber of the same-group. It is assumed that the impulses transmitted over the line do not operate directly upon the connecting device of the subscriber on account of their relatively high frequency, but are registered in the relay repeating device and are given out again more slowly.

The registering device in the relay repeater is connected up by the operation of the a key on the part of the operator, closing contacts IBET and ET. Relay AI is energized in the circuit earth, ISET, AI, A21 and battery. Relay A2 receives insuiilcient current through its winding A21, and does not energize. Relay RI energizes again over earth,IaI, M2 and 8! until relay F, which is short circuited by 35ET, deenergizes. After the release 01 the key comprising contacts I SET and 35ET relay AI locks up over earth, I3kli, I5al, A211, AI, A21 and battery, and relay A2 now energizes since both its windings are subjected to current. Relay F likewise energizes slowly over the resistance WM and the other operations take place as described earlier so that meanwhile relay A2 becomes energized.

When now relay RI is switched over again it can no longer energize since contacts IaI and 2112 are operated. Contacts 2111 and 28H connect alternating current transitorily to the line so that relay W2 energizes and brings up relay G by means of contact 54w2. Relay H energizes over 51g and relay K over 56h. Relay R2 does not energize in response to this brief impulse over earth inthe relay repeater, lead e, 5Ib(2), 50k: and 49102 since it is provided with means (a copper slug fitted to the core) making it slow to energize. The earth connected over 601122 and lead 1 is likewise inoperative before the registering device in the relay repeater has been connected up. The registering device is connected up after the release of relay W2, over earth, 44w2, 4517(2), 43h and the line d. Contact 43h is still operated since the relays release slowly one after the other,'after relay G has been disconnected. The operator can be informed over the speaking line that the connection has taken place, by means of an audible signal, so that the depressing of the key comprising contacts ISET and 35ET can be repeated if for any reason the connection does not take place, for example on account of a simultanecus'transmission of alternating current on the part of the subscriber. On the connecting up of the registering device the speaking line is out off in the relay repeater so that the transmission of alternating current on the part of the subscriber can no longer be a source of disturbance.

The desired number is now dialled and is taken up by the registering-device of the relay repeater.

The dial impulse contact 51m energizes relay RI intermittently over 5nsi and earth. Contacts NH and 28rI connect alternating current to the line and relay W2 is energized intermittently. The impulses are transferred to the registering device over earth, 6Ilw2 and the lead 1. During dialling relays G, H, and K hold up throughout the impulse trains. Relay R2 cannot energize while dialling is in progress since the lead e is disconnected in the relay repeater.

When the registering device has been set the impulses are released by the operation of a key comprising contacts 2IAT and 34AT. Since relays AI and A2 are still energized, relay A2 holds up throughout the time during which the key is depressed, over earth, 2IAt and 20a2, while relay AI is short circuited and releases. Relay RI is accordingly again energized over IaI, 2a2 and 6 and transmits an impulse over contacts 2'IrI and 28. 4. The impulse is limited by contact SI, for relay F is short circuited over 33aI and 34AT and deenergizes. After the release of the key relay A2 deenergizes and relay F becomes energized. The release period of relay A2 is smaller than the energizing period of relay F so that relay RI is not again energized. By means of the alternating current impulse relay W2 is energized transitorily and operates relay G over 54w2, the latter relay brings up relay H at contact 519 and this in turn energizes relay K over 56h. The alternating current impulse of the same duration as that causing the registering device to be connected up cannot energize relay R2 which is slow to energize. An additional setting in the registering device by way of contact 60102 is thus prevented. On the termination of the impulse earth is again connected to the d-lead over contacts 43h, 45b(2) and 44202, whereby the impulse transmission is released in the relay repeater. The operator receives an audible signal over the line until the impulse emission has terminated.

Subsequently the speaking line is again switched through in the current repeater to the subscriber, the latter being called by the transmission of ringing current over the jack Kli. This transmission of ringing current is more prolonged than the controlling impulses so that relay R2 energizes over earth in the relay repeater, lead e; 5i 21(2), k, and 49102, and transmits the ringing current over contacts "r2 and 4Ir2 to the subscribers who are now both called.

The clearing signal is given by one of the two subscribers by means of the magneto, whereupon relay W3 energizes and disconnects relay W2 at contact 31103. In addition to the clearing a drop in the supervisory cord circuit is operated, whereupon the plug is withdrawn and the jack contact I3kli is switched back to normal. Current passes through relays AI and A2 over earth, I3kli, "L, and IN. The two relays energize simultaneously so that contacts In! and 20:2 are switched over without relay RI having been energized. Relay L energizes over earth, I3kli, 22wI, MM, and 26d, and disconnects relays AI and A2 at contact I'IL. Relay A2 deenergizes rapidly but relay AI makes a delayed release. Meanwhile relay RI is energized over earth, IaI, 2a2, 6], RI and battery and connects alternating current to the line at contacts 21M and 2811. After the release of relay A2 the L relay holds up over earth, lakli, 22wI, 231, 251 until relay F deenergizes on the completing of the release. Contact IOaI disconnects relay D, 3011 disconnects relay E and 322 relay F. Over contacts 3e, 4d and 6f relay RI, which has in the meantime released, again becomes energized. Meanwhile, a second impulse is transmitted over the line. Thus, for the purpose of release, two relatively short impulses separated from one another by an interval corresponding to the release period of two-relays ar transmitted over the line. Relay W 2 is energized twice. Contact 39102 disconnects relay W3 and the relay repeater. 611 the first energizing of relay W2 relay G energizes. Contact iilg energizes relay H, and 5th relay K. Relay G holds up over 55102 and 5219(2). After the impulse the relays G, H, and K release in succession. When the second impulse occurs relay K has not yet deenergized and relay ET is energized. Contact liirt disconnects relay B and the release is effected by 27163). All the subsequent operations in the relay repeater have no bearing on the invention and will not further be described.

In the event of the subscriber transmitting alternating current from his magneto while the plug is being withdrawn, relay W l is energized and prevents the release by means of contact 22ml. Meanwhile contact ltwl holds relay Al energized over contact Mal and the latter relay holds up relay D over lilal. After relay Wl deenergizes the release proceeds as already described.

What is claimed is:

1. In a telephone system, a local exchange having magneto lines, a main exchange connected to said local exchange by a trunk line, means responsive to a call from a magneto line for signailing the operator at said main exchange by transmitting alternating current over said trunk line, means controlled by the main exchange operator for transmitting alternating current back over said trunk line to said local exchange to establish a connection with the calling ma neto subscriber, and means automatically opermm for delaying the transmission of the alter nating current by the operator controlled means in the event that the calling magneto subscriber transmits further alternating current at the time the connection is being established by the operator.

2. In a telephone system, a local exchange having magneto lines therein, a main exchange connected to said local exchange over a trunk line, means responsive to a call from a magneto line for transmitting alternating current over said trunk line to signal the main exchange operator, means controlled by the main exchange operator for transmitting an alternating current impulse back over said trunkline to said local exchange to establish a talking connection with the calling line, and means in said main exchange for automatically delaying 'thetransmission of the alternating current impulse to the local exchange 4. In a telephone system, a local exchange having magneto lines, amain exchange connected to said local exchange by a trunk line, means responsive to a call from a magneto line for signalling the operator at said main exchange by transmitting alternating current over said trunk line, means controlled by the main exchange operator for transmitting alternating current seizing, connecting, and releasing impulses of only a particular duration and sequence back over said trunk line to said local exchange, switching equipment at said local exchange responsive to said alternating current impulses for establishing a connection with a desired magneto subscriber, and means for delaying the transmission of the alternating current impulses by the operator controlled means in the event that the calling magneto subscriber transmits further alternating current which is of a different duration and sequence at the same time or partly before said impulses are transmitted by the operator controlled means to establish a connection.

5. In a telephone system, a local exchange having magneto lines therein, a main exchange connected to said local exchange over a trunk line, means responsive to a call from a magneto line for transmittingalternating current over said trunk line to signal the main exchange operator, a relay chain combination in said main exchange controlled by operator for transmitting alternating current seizing, connecting, and releasing impulses of a definite duration and sequence back over said trunk line to said local exchange, switching equipment at said local exchange responsive to said alternating current impulses for establishing a connection with a wanted local exchange magneto line, and means in said main exchange for temporarily delaying the transmission of said alternating current impulses by said relay chain combination in the event that the calling magneto line transmits additional alterhating current of difierent duration and sequence at the same time said other impulses are being transmitted to said local exchange.

FRIEDRICH LILL.

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