US1632343A - Automatic telephone system - Google Patents

Description

Patented June 14, 1927,

`UNITED STATES `ement orrice. *y

FRITZ LBBERGER, OF BERLIN-SCIEIMARGENDURE AND EDGAR HAHN, OF CHARLOT TENBURG, GERMANY, ASSGNORS TO SIEMENS t HALSEE AKTLENGESELLSCEIAFT, WERNERWERK, OF SIEMENSSTADT, NEAR BERLIN, GERMANY.

AUTMATIC TELEPHONE Application filed July 2, 1925, Serial No. 40,980, and in Germany V.'luly 18, 1924.

ln the co-pending l application of Lubberger Serial No. 41,034 filed July 2, 192V, of even date and its Figs. 1 to 3 is described and illustrated a method of setting up incoming and outgoing calls in a telephone system comprising main and sub-exchanges arranged for automatic operation. The invention described in the said disclosure enablessingle and multiple metering to be etlected tor such calls vand enableel a sub-exchange subscriber to be connected to the toll er:- change. The invention also enables the local battery at the sub-exchange to be re placed by a source ot current at the main f exchange, which provides the battery Voltage for operating and holding the switching de vices at the sub-exchange, this batteryl voltage being taken over one of the two speaking leads to the switching members at the subexchange. It the line resist-ance be high owing to the great distance between the subeizchange and the main exchange, and il turtliermore relays, resiet-ances, and choking coils be inserted in the lead, over which the holding battery current is taken from the main to the` sub-exchanges (in the above mentioned application this is taken over the speaking lead l5), then the drop ot potential in the line may be so great that the Voltage is insutlicient to operate and to hold the switching members at the sub-exchange The present invention removes this detect by using one special battery lead, Which, in ad: dition to the c and b speaking leads ot' the individual trunk lines, connects the sub-ei;` change With the main exchange,`and at the sub-exchange this special lead is connected by a relay to the individual batteryy leads ot' the switching members to be operated or held. l

lllith reference to the above mentioned application, a detailed description will be given hereafter ot the switching operations for setting up an outgoingcall from the subscriber N 300 ot the sub-exchange when a relay BA is used for connecting up the battery, which' relay functions when its circuit is closed.

rlhe drawing shows in Figs. 1 and 2 by Way of example one circuit arrangement.

l/Vhen the subscriber N 300 originates a call,

the following circuit is closed:

ilJ Earth, cattery, baclt. contacts cf 401 and contact (t 301. in each trunk line; thereby an earth potential is applied to the battery connecting up relay of each trunk line. The relay BA 100 in the trunk line VL I isoperated in the following circuit: l

2. Earth,battery,back contacts of 401 and o 401, relay R 400, leads bal 103, choking coil Dr 100, relay BA 100, double front conl tact a 301, earth.

Thereby in each trunk line a contact be' 101 o1 the `battery connecting up relay BA 100 connects the battery supply lead of the relays, one of which is associated with each trunk line (lead batt 101 in VL I), to the battery supply lead batt 100, which is common to alltrunk lines coming from the main exchange. rIhe coupling relay K 100 ot the virst idle trunk line and the relay C 100 are operated over:

3. Earth, double front contact t 301, relay K 100 Winding I, lead @al 101, relay C 100 Winding I, back contacts Z 103, zo 103 and asp 201, battery supply lead batt 100. The relay K 100 closes the operating circuit for the relay t 300 and closes the holding circuit tor the relays K 100 and C 100 as tolloWs:

4. Earth, relay T 300, Winding II of relay K 100, front contact 7: 103, lead dd 101, Winding H of relay C 100, battery lead batt 101, front contact ba 101, battery supply lead batt 100. Y

The battery connecting up relay BA 100 of the trunk line VL I is locked over the contact c 103 of the relay C 100, While the relay T 300 at its contacts t 301 and t 303 connectsthe calling subscriber through to the trunk line and marks him engaged to incoming calls by short circuiting the relay A 300 at the front contact t 305. Thus the relay BA 100 of the trunk line taken into use is further maintained energized by the operation ot the relay C 100 after the calling subscriber been switched through.x the the battery connecting vup relaysl-ll'i of the other` trunk lines are rendered operable by the subscribers calling relay A 300, which has been de-energized after the back contact t 305i has been opened and ithas been short circuited at the l'ront contact v305. rlhe relays fall back and again disconnect the batterysup Vply leads of the individual trunl; lines from thebattery supply lead batt 100.V

The calling, subscriber has new been' connected through Vas lar asthe preselector associated with his `tr'tinli line at they main exchange: Y

5. .Eartlnbatter front Contact ,r 4.01,

"relay R 500, back contact 501, lead ad 103, back Contact Z 103, lead ad 101,1'ront contacts L 101 and t 301, subscriber"s station Nl300`, number dial contact 'nu 300, front contacts t 303 and 71: 10:2, lead (M101,

L Arelay B100, earth.

' The relay R' 500 at the main exchange and the relay B 100 at the sub-exchange :are

operated.AV rEhe Vrelay R 00 thus starts)y up the preselector, Which in lrnotyn manner (see aboye'V mentioned application) hunts Y Yfor an idle lirst group selector and connects through'the leads ad 103 and bd 103 to the lirst, group selector, the relays M 400 and V 400 being operated at the saine time. The operation olf thev relay B 100 causes the back contact I) 103to be once opened and y at the front Contact 5101 the relay D 100 `is energized as follows:

y ll. Earth, front Contact Z) 101, relay -D 100, battery VleadV batt 101, Yliront contact ba "101,` battery supply lead batt 100.

Thereupon until the release of the connection, the ,relay D 100 loels itself over: 7. Earth', front Contact Z 101, relay D 100, battery lead Vbatt 101, front Contact a 101, battery supply lead bott 100.

The front Contact (Z104 renders the Y second trunk line available for an incom- 'tion at the main exchange, the selectin O opi'ng or outgoing call byconnectingthe battery supply lead batt 100 toV theY trunk line VL Hover the back contacts asp 201 and zo 103, 'trent contact (Z 104', back Contact d Il. Thefront Contact (l 10Q prepares the metering circuit.

The further building upY of 'the conneceration and they switching through ol' the' @peaking leads to the lrantedsubscriber are f described in the above mentioned applica and D 103, front ContactV 7c 10;l, meter Z,

300, front Contact 7c 105, battery lead batt 101, front contact ea 101, battery supply Y lead batt 100.,

l'ile'teringr having end-ed, the lirst group Vselector releases; relay M 100 falls bach and at contact mi L103 it interrupts the circuit ol relay V400, Which falls baeli alter some time as it is very slow acting.

Thus during` the time taken by the relay V 100 to release, the battery is disconnected from the lead ed 103. The relays R 4.00 and BA fall back; the relay BA 100 at its `Contact Zia 101 opens the battery lead batt 101 for the relays ol' trunk line VVL l. r1`he relays 'C 100 Winding ll, K 100 Windingjr ll, D 100 and T 300 fall back.

Foi-,calls from the main exchange to a subscriber N 300 of the sulrexchange the callingrelay AR 100 oit the trunk line is energized alter the preseleetor belonging to a trunk line'goin'g rto the sub-exchange has been taken into use 'from the second Kcircuiti selector over the leads mi 103 and er! 101 (see aforementioned application). Vt Contact (w1 1041 the relay All 100 cennects up the battery conneeting up relay BA 100.

9. Earth, battery, baci; Contact 101, Mliront Contact m L101, relay ll- 100, leads ed 103 and ed 101, choking coil Dr 100, relay BA 100, front' Contact er 104;, earthn The relay Bri 100 is operated and at its contact Zut 101 it connects the battery lead batt 101`With the battery sniff-pl;Y lead tft/,tf 100. Furthermore the relay ZV 100 operated as followsf f 10Q Earth, front Contact ai' 101, relay ZV 100, battery lead Lait 101. iront Contact 72a 101, battery supply lead batt 100. At its double Ytrent 'Contact ,er 102 the relay closes a holding' circuit 'for itself and a holding' circuit for the relay BA 100. The contact zu 101 opens the lead ed 101, hence the iu'eter Z 300 cannot operate. The conlact .er 104i renders the trunk line VL 1l available over:

11'. Battery supply lead bait 100v` bark contact asp 201, front Contact .zo 104.-, back ils Vcontact CZ Il, lead afl 102 ot the trunk line VL 1I. The selection of the subscriber N 300 of the sub-exchange .takes place in the llll ing` relay A 300 associated with his line is energized over the exciting,` circuit:

12. Battery supply lead batt 100, 'liront contact Zio 101, battery lead batt 101, 'front contactr fm Q02, relay ll" 200, t'ront contact z' 32, relay A 300, earth. The latter closes its double lront contacts c 301, etc., in all the trunk lines VL, and thus causes the relays C 100 and L 100 to operate in the trunk line VL Yl over the 'following circuit:

125. VEarth, double front contact e 301, relay l'f. 100 windlngl, lead cfZ 101, relay C 100 winding l, trent Contact m 201, relay L 100, battery lead hatt 101, front contact Za 101, battery supply lead batt 100. The re lays l( and C in the other trunk lines VL cannot operate, because the relays AS) 200 and lll Q00 have been operated at the end ot the selection, as shown in the alforenienu tioned application. rllhe relay L 100 locks over:

1.a. Battery supply lead bott 100, trent contactta 101, battery lead ZfZZ'Z' 101, relay L 100, trent contact Z 102, resistance lWL 100, back contact b 1022, earth, and connects at its :trent contact Z 1011 the lead ofZ 101 to the source ot ringing current. AThe relay K 100 closes the following circuit, in which it as well as the relay C 100 is locked and the relay T 300 is energized.

15. Earth, relay T 300, relay l 100 winding I1, front contact c 103, lead cZcZ 101, relay C 100 Winding Il, battery lead batt 101, front contact Zia 101, battery supply lead batt 100.

The relay C 100 at its contact c 101 disconnects the earth potential from the calling` relay ot the trunk line VL l. The re lay AR 100 alls back. The relay T 300 at .its trent contacts t 301 and t 303 connects the wanted subscriber N 800 to the, speaking leads UZ 101 and ZJCZ 101, hence the snbscrib er is now called over the following circuit:

1,6. Earth, battery, source of ringing` cnrrent, 'liront Contact Z 104, lead MZ 101, trent contacts Z: 101 and 301,subscribe1"s station N 300, number dial contact mi, 300, front contarts t 303 and 7s 102, lcadrfZ 101, relay B 100, earth. The relay P) 100 does not respond to alternatingl current. TVhcn the wanted subscriber answers, battery current flows over Vthe last mentioned circuit and the relay B 100 is operated. At its front contact Z) 102 it disconnects the holding,- circuit ot the ringing relay L 100 and at its front Contact Z 101 it connects up the relay D 100. The relay l.; 100 releases and at its Contact Z 108 it Vcloses the a lead afZ 101, so that the speaking route is now closed between the two subecribers.

At the end ot the conversation, when a subscriber hangs up his receiver, it will be seen from Fig. 8 of the aforementioned application that the relay M 400 at the preeelector VW is deenergized, the relay relt the wanted subscril'ier N 300 bo engaged when a call arrives from the main exchange,

the relay F 200 is energized in the `l'ollmring` circuit at the end el the numerical selection. 17. Battery supply lead Zia/t 100, itront Contact Zw 101., battery lead hatt 101, front contact m 202, relay E 2.00, trent contacts 32 and I; 305, earth. The relay F L00 connects up the busy tone relay BR 100 over:

18. Earth, bach conta ct Z 101., t'ront contact ljt' 201, relay BB 100 winding ll, battery lead bett 101, Ytrent Contact ZM, 101, battery supply lead Zunft 100. rthe busy tone relay lillJ 100 lccls'itsel'li over the o speaking lead (battery.

at the lead MZ 101 at the second group selector, preselcctor wiper V`W (Z), see the aterementioned application, and thence over:

19. back coirtactal 501,-'tront co-rtact Z' 502,y lead ad 103, back contact Z 10?), lead al 10.1, back contact C 101, front contact Z211 102, relay BR 100 windingl Il, earth.

At its Contact Zr 101, the relay BR 100 disconnects the calling, relay AR 100 :trom the lead afcZ 101. The relay AR 100 is deenerprized and opensv its contact m" 104. rlhe battery connecting' up relay BA 100 is maintained energized over the contact zo 102 until the release. rllhe calling subscriber is given the busy tone over an induction coil winding on` the relay BR 100 and the lead MZ 101 and MZ 103. Upon the release, the relays M /100 and V 1-00 at the main exchange and the relay BA 100 at the sub-exchange are deenergized. Upon releasing', the relay 11A, 100 opens the battery lead hat?? 101, hence the relay ZV 100 talls back.

It the sub-exchange be provided with a battery connecting up relay (BA 100) operated by cnrrent normally flowing.: over the line Jfrom the main exchange, the circuit changes are similar to those above described :tor incoming and ontaoinggj calls to and 'trom the snb-exchange (Fig. 2.)V

Normally the relay BA 100 is energized as fellows:

20. Earth, battery, back contacts (7 101 and c 4101, relay R 100. lead ZNZ 103, choking` coil Dr 100, relay BA 100, earth.

Thus the battery load batt 101` ot the trnnlrline VL I is normally connected to the comlnon battery supply lead batt 100 by the Contact Za 101. Hence the relay R 400 at the main exchange is not energized over the high resistance winding of the relay BA 100, and it only operates when, upon a subscriber of the sub-exchange (ll 300) being called, the calling relay A 300belongingy to this subscriber is connected in shunt tothe relay BA 100.

By a call of the subscriber N 300 of the Vsub-exchange the relay lt L100 at the main 201, battery supply lead batt 100. The fui:-V

ther circuit changes and switching through operations, as well. Vas the selecting, take4 place in the manner above mentioned. The release is effected after the conversation has ended Vand the metering operation has been completed; this entails as before the deenergization of the relays M 100, V 100 at the main exchange. During the time taken by the relay V400 to release slowly, the lead bd 103 loses its voltage, the relay BA 100 at the sub-exchange now. falls back and interrupts the battery supply lead batt 101 of the holding relays at the sub-exchange, hence the relays can return to their normal position. y

Since the relay BA 100 is normally energized, battery voltage is applied to the battery supply lead of the switching relay of each trunk line VL. when a call is made from the main exchange to the sub-exchange.

Only when release takes place, is battery` disconnected from the lead 71d 103 by thie contacts m 101 and v 101 at the main ex-y change; thereby the relay 'BA 100 and the holding relay at the sub-exchange release as before, i,

`1What is claimed is:

1. lnan automatic telephone system, a

- main and a subexchauge, a group of trunks between said exchanges, a source of current at said main exchange, a single battery conductor between sai-d exchanges, automatic switching equipment: in said exchanges, subscribers lines terminating in said exchanges,

means controlled by a calli ng subscriber for and means for opera-ting said relay from the main exchange battery over the associated trunk, said relay operating to connect the switching` equipment associated with the selected trunk with saidbattery supply conductor.

3. In a telephone system, a main and a sub-exchange, a group of trunks between said exchanges, said group comprising talk ing` conductors and a battery supply conductor, switching` equipment in said: exchanges, a source of currentat said main exchange, a battery control relay in said subexchange, subscribers lines terminating in said exchanges, means responsive to the re-V moval. of the reeeiver'from one of said sub- 'exchangesubscribersr lines for energizing vsaid exchanges, a relay associated with each of the trunks of said group arranged to connect that part of said switching equipment associated with that trunk to the battery conductor, means responsive to the initiation of a call by one of said subex change subscribers for energizing all of said relays, means for selecting one of said trunks, and meansrfor releasing all of said relays exceptt-he one associated with said selected trunk. Y

5.111 an automatic telephone system, a main and a sub-exchange, a plurality of trunks between said exchanges, a source of current at said main exchange, a battery conductor common to said trunks between said exchanges, switching equipment in said exchanges` a relay atsaid sub-exchange as` sociated with each of said trunks, contacts in said battery conduct-or controlled by said i In witness whereof, I hereunto subscribe my name this 12th day of June, A. D. 1925.

EDGAR HAHN.

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