US1433594A

US1433594A - Telephone-exchange system

Info

Publication number: US1433594A
Application number: US349868A
Authority: US
Inventors: Rand S Bailey
Original assignee: American Telephone and Telegraph Co Inc
Current assignee: AT&T Corp
Priority date: 1920-01-07
Filing date: 1920-01-07
Publication date: 1922-10-31
Anticipated expiration: 1939-10-31

Description

R. S.Y B'LEY.

TELEPHONE EXCHANGE SYSTEM.'

APPL ICATION FILED JAN. 7 1920.

melmaY ont. 31, 1922.

/Hvenoh Hand Sfephen 25 a//e by MQ a trunk such as T has been tested and found idle, ringing current will be sent over the conductors 10, l1 of the trunk leading to the inanual exchange to energize a relay l2 thereat. The circuit therefor is as follows: ground, wiper 1li in its third position, brush `90, terminal conductor 82, tip spring and contact of jack 15, winding of relay 12, contact and ring spring of jack 15,*conductor 10, Contact 83, brush 81, wiper 16 and its third contact, winding of ringing cutoff relay 17, front contact and armature of relay 18 which is energized in the third position of the side switch wipers, to a source of ringng current 19. Attraction oit' the armature or' relay 12 causes a signal 2G to be dis played indicating to the operator that a call has arrived.

.The operator thereupon inserts plug 25 into jack cutting off relay 12 to extinguish lamp and operating relay 26 of the cord circut B, the circuit therefor being from grounded battery, resistance 13, sleeves of jack 15 and plug 25, winding of relay 26 to ground. Relay 26 attracts its armatures thus placing an alternatingcurrent bridge across the talking conductors of the cord circuit B.

The insertion of plug in ack 15 transfers the circuit itor ringing current to relayy 50 oi said bridge over the following path: ground, third contact and wiper 14;,brush 90', contact 82, conductor 11, tips of jack 15 and plug 25, conductor 31, lefthand nor mal contacts of relay 32, conductor 33, upper spring and normal contact of the answering cord ringing key 80, conductor Bil, left-hand winding of retardation coil 36, inner rightarmature and make contact of relay 26, normal contact of relay 40, inner righthand armature `and back contact of relay 41, right-hand winding of ring-up relay 30, condenser 42, front contact and outer righthand armature of relay 26, right-hand winding of retardation coil 3G, conductor 46, com tact and lower spring of the answering cord ringing key 80, conductor e157, normal contacts oi the lett-hand inner armature of reT lay 32, conductor 48, ring of plug 25, ring or jack 15, conduct-or 10, brush 83, contact 81, wiper 16 and thirdcontact, winding of relay 17, iront contact and armature of relay 18 to source of ringing current 19. Re-

lay 30 locks up under control of key 50. TheA operator then actuates the ylistening key 50, thus bridging her head-set across the talking conductors oi the cord circuit B. Actuation of thel listening key opens the locking circuit to: relay 30, and causes energizati'on of relay 10. which interrupts the alternating current bridge in the cord circuit B and substitutes therefor a direct current bridge resulting in thel side switch at theI connector switch moving from position 3 to 4 in the well-known manner. `Relay -LO is energized over the following path: grounded battery, winding ci relay 40, outermost lower contacts oi? key 50, back contact and lett-hand armature ot relay 41, and lower make contacts of the right-hand inner armature ot relay 26 to ground. Relay l0 is held locked'up over its left-hand armature and front contact. The alternating current bridge was interrupted at the normal con. tacts ont relay 40 and the direct current bridge was established at the right-hand armature land alternate contact of relay 4:0.

The operator having ascertained the 'number of the desired line, plug 52 is inserted into jack 53 and ringing key 55% is actuated to send ringing current over --the line to substation C in the usual manner. insertion of plug 52 into ack 58 energized relay 54 thus disconnecting line relay 56 from substation C and causing supervisory lamp to light over the following path: grounded battery, lamp right-hand armature and back contact of relay 41, sleeve of plug 52, sleeve otjack 53, winding of relay 54C to ground.

in response to the ringingsignal, the subscriber at substation C removes the receiverV from the switchhook, whereupon relay 58 of the cord circuit is energized by current from the line relay 5 of the connector circuit at the autom interchange flowing over the talking conductors oiC trunk'l, cord-circuit and ythrough the loop of substation C. The winding of relay is of low resistance. and although there are other paths :tor the current from the automatir^` exchange through the winding of retardation coil 86 and the shunt 59, sui'iicient current flows through relay to energize it, Upon energization, relay through its iront contact and arma# tur-e closes a circuit to energize relay 41 ifl'iicli, upon attracting its armatures, causes the cord supervisory lamp to be extinguished by interrupting the circuit for said lamp at its outer rightehand armature and back contact, and the control ci' 'the automatic switch ling apparatus to be transterred vfrom the (ford circuit to the substation C by inter-u rupting the holding circuit 'tor relay 4i() at the lett-hand armature and back contact ot relay 4:1. Talking current tor substation C is supplied from relay 5 of the connector circuit over the talking conductors of the trunk andcord circuit, through the relay 58 and the shunt 59 thereof and thence over the talking conductors of the cord circuit B and the line leading tosubstaticn C. The relai;Y

5 in attracting its armature operates relay` 94 which locks itself to ground at oid-normal switch 95. In attracting its lett armature,

relay 94: removes the control of the release of the switches from the subscriber at substation i by shitting the battery connected to theright winding of relay 91 to the front contact of relay it 'the conclusion of conversation, the subscribers. restore the receiversfto the switchhooks. The replacement of the `receiver at station C releases relay 5 which releases re-` lay 91. Relay 91 releases slow relay 92. The retractedcondition of the armatures of these latter relays closes the circuit `of release magnet 93 which restores the connector. The retraction of the right' armature of slow relay 92 removesr ground from the release wire 9G resulting in the release of the Vpreceding switches in the well-known manner. rlhe restoration of the receiver to the switchhook at station C' either before or after `the subscriber at station A hangs up releases relay 58 since ciu'rent ceases to flow through this relay. Relay 5S in retract-ing i/tsfarmature opens the circuit :for relay 411 which in reti-acting its armatures rie-establishes the alternating current bridge `across the talking conductors of the cord circuit so that should another` call Aarrive over the trunk circuit T before the operator has withdrawn the plugs, subscriber C will not be signalled due to the energization of relay 30 which responds to ringing current from the distant office and locks up thereby interrupting the continuity of the talking conductors leading to station C. The ringing current is thus prevented from passing through and signaling station C. Relay L,Ll in releasing also completes a circuit for supervisory signal indicating to the operator that conversation has ceased.

If the trunk T is selected before disconn nection takes place,'relay 80 will be energized thereby completing a circuit for signal 65. This signal serves to indicate to the operator that another callhas arrived from the automatic exchange. The operator thereupon removes plug` 52 from ack actuates listening key 50 and then proceeds as with any incoming call.

lnthe foregoing, a description has been given of the operation `of cord circuit B for completing an incoming call from an automatic exchange. A brief description of the operation and use of the cord circuit for completing an outgoing call will now be given.

ln response to the removal of thereceiver from theswitchhook at station C, line relay 56 and in `turn line signal 60 operate. The operator in answering inserts plug 52 into jack 53 whereupon relay 54 operates thereby cutting olf line relay 56 and eX- tinguishing linesignal 60. Supervisory relay 58 operates over a circuit including ground. back contact and inner right-hand armature of relay 26, left-hand winding of retardation kcoil 36, upper normal contacts of ringing key 54C, tips of vplugs 52 andjack 53, the substation loop, rings of jack and plug 52, lower` normal conta-cts of ringing key 54h winding `of relay 58 and shunt 5t" thereof in parallel, outer vleft-hand armature andback contact of relayxBO7 righthand winding oiireta'rdation coil 36, outer right-hand armature and back contact ol relay 2G and grounded battery. Relay 58 in operating' completes a circuit at its righthand armature and front contact for relay 4l. The operator then actuates listening key 50-and upon being informed by the calling subscriber that station A. at the automatic exchange is desired, inserts plug 25 into jack l5. Relay 26 then operates over the path previously traced.. Relay 26 in attracting its righthand armatures disconnects battery and ground from the talking conductors and current fromthe iirst selector at the automatic `exchange is substituted therefor over linder N which maintains relays 58 `and 4:1 operated. The oper` `ator then actuates impulse sender S to transmit impulses over 'the trunk T to the automatic exchange to set the selector switches and the connector thereat in accordance with the number desired in the well known manner. f f

Impulse sender S is provided with a set of' contacts T0 which are actuated a numberl of timesin accordance with the digit dialed to set the switches and with a set of contacts 7l which are closed when the dial is `in an olf-normal position. The contacts 7l are closed upon the initial movement of the dial and remain closed during the entire movement and until the `dial Vreturns to normal. lVhen sender S is actuated, con,-

tacts 7l are closed thereby completing a circuit for relay 32, said circuit including the uppermost contacts of key 50. Relay in operating disconnects the calling from thejanswering end ofthe cord circuit and connects battery and ground to the talking conductors of the answering end. After the last series of impulsesv have been sent, relay 32 1n deenergimng renders the cord circuit continuous. Key 50 is then restored to normal, whereupon talking current is fed to station C from the connector at the autoA matic office in the well-known manner.

llpon completion of conversation, subscriber (l in restoring the receiver to the switchhook opens the loopleading to the automatic exchange whereupon supervisory relay 58` deenergizes and the switches at the automatic exchange are released in the usual manner. Relay 58 in retracting its armature opens the circuit for relai/141 whereupon ring-up relay 30 is bridged across the talking conductors.

l Supervisory `lamp 55 lightsindicating to the operator lUO as before mentioned that a call exists on trunk T whereupon 4plug 52 will be-removed and listening key operated to inquire from the calling subscriber the number desired.

llVliat is claimed vis l. in a telephone system, a calling line and a. called line, means including automatic switches, ak trunk line and a cord circuit tor interconnecting said lines, a bridge across said cord circuit eliective until the response of the called subscriber for preventing `said switches from releasing, and `means fcontrolled over the calledy line tor opening said bridge.

` 2. lny a telephone ing line and a called line, means including automatic switches, a trunk line and a cord circuit for interconnecting said lines, an alternating and a direct current bridge for said cordcircuitoperator controlled .means for removing said alternating current bridge andsubstituting therefor the direct current bridge, and means under the control of the called line 'tor removing said direct current bridge. y, c

In a telephone exchange system, a cali,- ing line, a called line, means including anto-` lnatic switches and a cord circuit 'for intei-, connecting said lines, manual means in said cord circuit lior placing a holding bridge across the cord circuit until the called sub. scriber answers, automatic means for removing said bridge .when said called line answers, and means for substituting a bridge at the called station. A

hln a telephone-system, a calling` line.l a called line, apcord circuit, means including automatic switches for rinterconnecting said lines over said cord circuit, a key in said cord circuit, a relay actuated in response tothe actuation oi' Said key, adapted to place a holding bridge across the cord circuit, a second relay in said cord circuit actuated in response to the answering of the called subscriber 'for disabling` said holding bridge, and meL is tor substituting a holding bridge at the called station. l

lfu a telephone system,y two subscribers1 lines, a cord circuit, means including autoniatic switching apparatus for establishing a connection between said lines over said circuit, and for impressing alternating current on said. cord circuit, means controlled over one of said lines for releasing the automatic switchingapparatus and for immediately7 causing an alternating currentbridge to be connected across the talking conductors of the cord circuit, and means controlled by'4 said bridge for preventing alternating current from operating the bell at the called station,

' 6. ln a telephone system, two subscribers lines, cord circuit, means including automatic switches for establishing a connection between said lines over said cord circuit,

-and for impressing` exchange system, a call.

alternating current controlled on said cord circuit, means over the subscribers lines for releasing i the automatic switches, a source ot current associated with said automatic switches -for supplying talking current for said lines, a relay associated with said cord circuit actuated by said source of current, an alternating current bridge norm( lly disconnected from said cord circuit means controlled'by saidv relay for connecting said alternatingcurrent bridge to said cord circuit, and means controlled bysaid bridge for preventing alternating current from operating` the bell ot the called station.

7.111 a telephone exchange system, an automatic exchange, a manual exchange, two subscribersj lines, one terminating at each ot'said exchanges, `a cord circuit at said manual exchange, means including automatic switches for establishing a connection. between said lines vover said cord circuit, means controlled over the subscribers lines for releasing saidswitches, a source oi ringing current at said automatic exchange, a relay associated with said cord circuit responsive to the ringing current adapted upon actuation to interrupt the continuityv ot the talking conductors leading to one oii'said lines, a locking circuit for said'relay and -ineans tor opening said locking circuit.

8; In a telephone exchange system, a calling and a called line, a cord circuit,\means including automatic switches for connecting said lines over said cord circuit, including a pair of talking conductors, means or sig'- naling said called line, a holding bridge in .said cord circuit effective until the subscriber ot said called line answers, means for disabling said holding bridge upon the response et the subscriber of the called line, means tor connecting an alternating current bridge across rthe talking conductors ot' lsaid cord circuit upon restoration of the receiver to 'the switchhook at the station of the called subscriber, and means controlled by the re-A placement oif the receiver at the subscriliers stations for releasing said switches 9. In a telephone exchange system, two subscribersv lines, a station for each line, a trunk circuit, a cord. circuit, means includ- -ing automatic switches for establishing a connection between said lines over said trunk and said cord circuits, signaling responsive means associated with said cord circuit normally disconnected therefrom and means for releasing said, switches land connectingy said signal responsive means to said cord circuit when one of said subscribers restores the receiver to the ,switchhook 10'. In a telephone evchange system,l in combination, a trunk circuit including automatic switches extending from a first to a second ollice, a telephone line terminating at the second office, a cord circuit thereat for llO connecting the trunk circuit with the telephone line, means `cont-rolledover said line for releasiiig said automat-ic switches, relay in the cord circuit responsive to alternating current, said relay being disconnected from said cord circuit when the receiver of the telephone line is removed from the switchhook, and means for bridging said relay across the talking conductors of said cord circuit when the receiver is restored to the switchhook. y

11. ln a telephone exchange system, an automatic telephone exchange, a manual telephone exchange, means including a trunk circuit or extending a call from said automatic to said manual exchange, a cord circuit tor connecting said trunk circuit to a called subscriber at said manual exchange, a ringing rela)v in said cord circuit actuated in response to the sending of ringing current over said trunk circ-uit, a key in said cord circuit adapted upon actuation to disconnect said ringing` relay and establish a holding bridge in said cord circuit, and means in said cord circuit adapted to remove said holding bridge upon the response of the called subscriber, said means being arranged to again connect said ringing relay to said cord circuit upon restoration ot' the receiver to the switchhook,

l2. In a manual telephone exchangma trunk circuit incoming from an automatic exchange including automatic switches, terniinating in a jack, a cord circuit for extending a connection 'from said automatic exchange to a called substation in said manual exchange, a holding bridge in said cord circuit effective until said called substation answers, substitute bridge at the called station. closed upon the removal ot the receiver thereat for controlling the release ot said automatic switches, and an alternating current bridge in said cord circuit effective when said called substation has restored the receiver to the switchhook.

13. A telephone exchange system coml prising a manual telephone exchange, a switchboard, telephone lines terminating therein, a trunk circuit extending from said switchboard to an automatic exchange and including automatic switches thereat, a ringing relay in said cord circuit normally disconnected therefrom adapted to open up the talking conductors of the calling end of said cord circuit upon energization, manual and automatically controlled means for connecting said relay to said cord circuit, and means controlled by the subscriber :for releasing said switches.

141-. In a telephone exchange system, a trunk circuit extending from an automatic to a manual exchange and including automatic switches, a calling subscribers line at said automatic exchange, a called subscribers line at said manual exchange, a cord circuit at said manual. exchange 'for connecting saidcalling with said called line, a holding bridge in said cord circuit eiiective upon the response of the operator to the call from the called subscriber, a. relay in said cord circuitactuated in response to the removal ot the *receiver 4trom the switchhook on the calledl subscribers line for disabling said holding' bridge, means for substituting a holding bridge at the` called station, and means controlled by the opening of the bridge forreleasing said automatic switches. 15. In a telephone system, an automatic oiiice, a manual ofiice, a cord circuit thereat, called lines terminating in jacks at said manual oliice, a trunk extending from said automatic oliice tosaid manual oliice and terminating in a jack thereat, a calling station having a dial for setting the switches at the automatic othce to pick out said trunk, a signal operated upon the selection of said trunk, a bridge across said cord circuit, a manual switch controlled by the operator for causing the closure ot said bridge, means operated thereby for transferring the control oi' the release ot said automatic switches to said bridge, means controlled by the called party for closing another' bridge at the called line to hold said switches set and for opening said itirst bridge, and means controlled by the called party for opening said latter bridge to release said automatic switches.

16. In a telephone system, an automatic office, a manual office, a cord circuit thereat, called lines terminating in jacks at said manual office. a trunk extending from said automatic oliice to said manual oiiice and terminating in a j ack thereat, a calling station having a dial for setting the switches at the automatic oliice to pick out said trunk, a signal associated with said trunk jack, means at said automatic oilice for impressing alternating current on said trunk to operate'said signal, an alternating current bridge adapted to be closed across said cord circuit upon the insertion of the answering plug, a direct current bridge, a key in said cord circuit for placing the same across said cord circuit, means operated thereby for disconnecting said ringing current, and a relay operated by the response ot the called party for opening said direct current bridge and substituting a bridge at the called stationto control the release of said automatic switchese y1'?. In telephone system, a talking connection including a calling automatic substation, a trunk includingv automatic switches, a cord circuit and a called manual station, means for impressing alternating current on the cord circuit from the automatic oliice, a bridge at the called station for controlling the release of said switches, and an alternating current bridge at said cord circuit including a relay adapted to liov impressing alternating cuilent'on said cord Circuit to operate said relay, and al signal in said Cordeircuit controlled by said relay. l0

n testimony whereof, I have signed my name to this specifica-tion this 5th day of January, 1920. v

, RAND SBAILEY.