US1296677A - Telephone-exchange system. - Google Patents

Description

E. R. LUNDIUS.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED MAY 3 I918.

Patented Mar. 11,1919.

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ERIC R. LUNDIU'S, OF BROOKLYN, NEW YORK, ASSIGNOR TO"WESTERN' ELECTRIC COMPANY, INCORPORATED, NEW YORK, N. Y., A CORPORATION OFNEW YORK. i

TELEPHONE-EXCHANGE, SYSTEM;

To all whom it may concern:

Be it known that I, E1210 R. Lmvoros, a

citizen of the United States, residing at ing purposes, and which'are equipped with I trunk circuits extendlng to privatebranch exchanges, chief operators desks and like positions.

In systems, of this type employing trunk circuits extending from a switchboard posi-' tion to a chief operato'rs or information operators desk and cooperating at the switch: 7

' .board position with an automatic ringing link circuit, it is usual to cause the disconnection of ringing current from the trunk circuit upon connectionbeing made therewith at the answering or incoming end.

' There is usually considerable disturbance in the talking circuit attending the'disconnection of the ringing current and the subst tution of the direct current therefor, which, if

the answering operators receiver be connect edto the talking circuit, produces very severe clicks in the receiver. It is an object of this invention to provide a system of this character in which the receiver of the answering operator is not connectedwith the talking circuit until after ringing current has been disconnected and direct current substituted therefor, thereby practicallyeliminating all disturbance in the receiver of the answering operator. It is'also an object of I this invention'to provide improved slgnaling means for systems of this character.

In accordance with this invention the ringingcurrent is automatically connected with the trunk circuit upon the connection of the link circuit therewith and upon connection being madewith the trunk circuit-at the'incoining end, apparatus respondsto con-V nect across the trunk circuit a low impedance bridge for causing the disconnection of the ringing current from the trunk circuit, after which the normally open talking con ductors of the trunk circuit are closedtoex- V tend the talking circuit to thedesk; x l

' For amorecomplete understanding of this Specification of Letters Patent.

with the accompanying drawing Patented Mar. 11,1919.

Application filed May 3, 1918. Serial No. 232,269.

invention, reference should be had to the following description considered in connection one embodiment thereof. p j

There is shown in the 'drawingan'auto 'matic ringing link. circuit A located at a switchboard position, from which a trunk circuit B'extends to an operators desk,'or other switchboard position; At the desk there is located a cord circuit C, by means of which connection. may be-made with the in- 7 coming end of the trunk circuit. The apparatus shown to the left" of the dotted line illustrating 11 is loc'atedat the switchboard 'X, and

that located to the right of the dotted line 11 may be located at the deskvor second switchboard'Y.

The nature of this invention is such that it is thought that it will be clearlyun'derstood from a'description of the operation of thesystem disclosed in the drawing and it will be so described.

The originating operator desiringv to es tablishv a connection by way of the trunk circuit with the desk operator,inserts plug 5 of the cord circuitA into jack 6 of the trunk circuit B, whereupon lamp 7 lights and relays 8 and 9 operate over a circuit 7 from battery'through the lamp 7, winding of relay 8, sleeve contacts ofthe plug 5 and the jack 6, contact 10 of relay 11, winding of-relay 9 and contact 12 of relayll to ground. Relay 8, in operating, causes the operation of'ringing relay 13 over a circuit 7 from battery throughresistance 14, winding of ringing relay 13, normal contact ofrelay '15, c ontact of tripping relay 16 andthe contact'ofrelay 8 to ground. The operation of ringing relay 15 connects a source of ringing current'l'? through thewinding of the trip.- ping relay 16 to the trunk circuit B. The

operation of relay 9 causes the lighting of lamp 18 over a circuit from. battery through the lamp 18, contact 19 of relay11 and-the I contact ofrelay 9 to-ground.

The deskoperatorobserving the lighted condition of'the lamp 18 inserts plug 25 of the cord circuit A intoijack 26 of the trunk circuitB, whereupon the lamp 27 isilighted and relay 28 operated overa circuit from battery through the-lamp 27 resistance 29, sleeve contacts of thedplug 25"and the jack 26, lower winding of relay 2 8 and contact 30. of relay 31 togroundl .Relay28, in o erat- 1 Y ing, short-circuits condenser'32 and connects of the trunk circuit B; The right and lefthand windings of this retardation coil 33 are of low impedance, while the middle winding is of high impedance. The. tripping relay 16 will not operate when the three wlndin'gs" 0f the retardation coil 33 are connected in series therewith. Relay 28, in operating, also causes the operation of relay 11 over a circuit from battery through the lamp 7, Winding of relay 8, sleeve contacts of the plug 5,

the jack 6, contact 34 of relay 28 and-the Winding of relay 11 to ground. .Relay" 11, in operating, opens'the circuit of and efiaces thelamp 18, removes relay 9 from the sleeve conductor, thereby deenergizing this relay 9, andfby the closure of its contact 35, connects relay 9 in ,parallel with the middle or high impedance winding of the retardation coil 33; The closure ofcontact 36 of relay 11 establishes a locking circuit therefor, thereby rendering this relay independent of the'condition of relay 28. Theconnection of relay 9 in parallel with the high impedance wind ing of the retardation coil 33 lowers the impedance'of the bridge to such an extent that the tripping relay 16 operates.

The tripping relay 16, in operating, removes thefshort circuit from the winding of the relay 15, which thereupon operates, locks up and establishes a short, circuit for the ringing relay 13, which is thereupon deenergized to disconnect the source of ringing current from the trunk circuit B. Ringing relay 13 in closing its normal contacts con-' nects a source'of dlrect current with the talkin conductors of the trunk circuit.

elay 9 is responsive to direct current but is non-responsive to-ringing current. That is, while there isa partial attraction of the armature of relay 9 when its winding is traversed by ringing current, this attraction is not sufficient to permit the continued 'closure of its contact. Upon the disconnection of ringing current from the trunk circuit B,

'a source of direct current is substituted therefor so that the relay 9 then I operates over a circuit from battery through the winding, of supervisory relay 40, lower normalcontact of ringing relay 13, ring contacts of the plug 5 and the jack 6, left-hand winding of impedance coil 33, contact 35'of relay 11, wi nding of relay 9, right-hand winding of retardation coil 33, contact 41 of relay 28, tipcontacts of the jack 6 and the plug 5,

' upper normal contact of the ringing relay 13 to ground. Relay 9, in operating, causes the operation of a slow-release relay 42 over a circuit froln'battery through the normal contact of slow-release relay 43, normal contact of relay 44, winding .oiislow-release relay 42, contact 45 of'rela'y 11 and the contact of relayj 9 to ground. v.lRelay'42, in operating,

causes the operation of relay 44 overa cirright-hand alternate contact and winding of relay 44, contact 45 of relay 11 and thecOntact of relay 9 to ground. The operation of relay 44 opens the circuit of relay 42, which thereupon releases its armature. Upon the closure of the left-hand contact ofrelay-42, relay 31 operates over a circuit from battery through the winding of relay 31, left-hand alternate contact of relay 44, left hand contact ,of relay 42, contact 45 of relay 11 and the contact of relay 9 to ground. Relay 31, in operating, opens its contact 30, thereby removing the short circuit from the upper winding of relay 28, which increases the resistance in circuit with the lamp 27 to such an extent that the lamp is efiacedQ Relay 31, in operating, also closes normally open contacts in the talking conductors of the trunk circuit. Upon the closure of the circuit through supervisory relay '40, this relay oper ated, establishing about the lamp 7 a shunt circuit including resistance 14 for efia'cing the supervisorylamp 7. The originating operator may thereupon actuate listening key 46 to connect the telephone set in circuit. The deskoperator may actuate listening key 47 to connect the desk operators telephone set in circuit, that is, if this listening'key 47 circuit, the originatingoperator may resignal the desk operator by causing the flashing'or intermittentiglowjof the lamp 27. This is brought about by the repeated withdrawal of the plug-5 fromand the insertion thereof into the. jack 6. 'Upon thewithdrawal of'the plug 5 from the jack 6, relays restores all apparatus 9, 11, 44 and'31 release their armatures. V,

The release of relay31 closes its contact 30 thereby short-circuiting the upper windin' of relay 28. The resistance in circuit wit the lamp 27 is thereby reduced to suchan extent that the lamplights. The closure of V the upper and lower normal contacts ofrjelay 3l establish'es a short circuitabout each of. the co11densers' '48 and 49, thereby to pro- Vi-de discharge. Paths i hese condeIiSerS, .S'o' i that when'the normally open contacts in-tlie talkingconductors are 'closed upon'the sc nt zcti efjqf si t 3 hr w be no discharge from the condensers over the talking circuit. The connecting of these condensers in circuit with the talking conductors when in their discharged c0nditi0n prevents disturbancein the talking circuit. The

reinsertion of the plug 5' into the jack 6 causes the operation of relays 8 and '9, as before. Relay '8 operates the ringing relay to connect ringing current with the trunk circuit, and relay 9 may light the lamp "18 momentarily but for no longer, for relay 1f operates practically simultaneously with the operation of relay 9, and in so doing,

opens the operating circuit of the lamp .18 and the energizing circuit of relay 9. Relay 11, in operating, also connects the relay 9 in shunt of the high impedance winding of the retardation coil 83, thereby to cause the operation of the tripping relay 16 and the consequent disconnection of the ringing current from the trunk circuit, in the manner hereinbefore described. Relay 9 then operates to energize the slow-release relay 42, whereupon relay 44 is energized and'locked up to release relay 42. Upon the release of this relay, relay 31 operates in the manner already described to complete the talking circuit. Each time the plug 5 is withdrawn from the jack 6, the lamp 27 islighted and the intermittent lighting of this lampserves as a signal to the desk operator, who,'upon observing the flashing thereof, may actuate the listening key 47 to connect the telephone set in circuit.

If a calling telephone line (not shown) is connected by way of the automatic ringing cord circuitA and the trunk circuitB with the deskoperators cord circuit'O, the desk operator may converse directly with the calling subscriber. After furnishing to the subscriber suchinformation as is desired, the desk operator may wish to signal the "originating operator. This may be done by the repeated actuation of key 50, to cause the flashing or intermittent operation of the supervisory lamp 7 of'the cord'circuit 8. The

actuation of t e key50 by the closure of the upper contact, short-circuits the windings of relay 28, thereby causingthis relay to release its armatures to open up the direct current bridge of the talking conductors'which includesretardation coil 33' and relay 9. Su-' pervisory relay 40 thereupon releasesitsarmature to remove the shunt circuit from about lamp 7. This lamp 7 thereupon-lights. The closure of the lower contact of the key 50 energizes the slow-release relay '43, which opens its normal and closes itsaltern'ate'contact. The opening of the normal contact of relay 43 prevents the energization of relay 42 after relay 44 has'released its armatures,

following the deenergization of 'relay'9. The closure of the alternate contact'of relay 43 prepares anenergizing-circuit for re1ayf44 which is independent of the relay 42. I Relay r 9 releases its armature upon the opening of the direct current bridge of the talking con.- ductors, and in so doing, opens the circuits of relays 31 and 44 which thereupon release their armatures. The relay 31, in releasing its armatures, opens the talking conductors of the trunk circuit. Upon the restoration of the key 50 to normal position, the short circuit is removed from the lower Winding of relay 28 which thereupon operates, reestablishing the direct current bridge ofthe talking conductors. Relay 40 and relay 9 thereupon operate, the former causing the efi'acement of the lamp 7 and the latter causing the operation of relay 44. Relay 44, in operating, causes the energization of relay 31, which removes the shortcircuit of the upper winding of relay 28 and closes the normally open contacts of the talkingconductors. Relay 43 being slow to release, maintains its alternate contact closed after the opening of the lower contact of the key 50, until the contact of relay 9 is closed. Therefore, relays 28, 9,44 and 31 are the only relays which function to control the opening and the closure of the talking conductors while the desk operator is signaling the originating operator. The lamp 7 is llghted each timethe key 50 is actuated, and

the intermittentlighting of this lamp serves erator may hear the originating operator an- 'swering and stop the repeated actuation of the key 50.

What is claimed is:

l. Atelephone exchange system compris: ing a trunk circuit extending from a first to a second switchboard, a link circuit at the Zfirst switchboard, a source of ringing current, means responsive to the connection of the llnk circuit with the trunk circuit for with, a link circuit at the second switch- *connectinga source of ringing current there- V board, a relay responsive to the connection.

of the second link circuitWith the trunk ,circuit, and a low impedance bridge for the trunk circuit'established upon the response of the relay for causing the disconnection of 1 .the source of ringing current from thetrunk circuits r ,2. A telephoneexchange system compris-"12 5 ing a trunk circuit having normally open 1 talking conductors extending from a first to a'second switchboard, a-link circuit at the i first switchboard, ais'ource ofjringingcur I :rent,means respons1ve tothe connection of the link circuit with the trunk circuit for connecting the source of ringing current therewith, a signal control relay in the trunk circuit responsive to the connection of the link circuit therewith, a link circuit at the second switchboard, means responsive to the connection of the second link circuit with the trunk circuit for connecting the signal control relay in bridge of a the talking-.0011- ductors, means in the first link circuit responsive to the connection of the signal control relay in bridge of the talking conductors for disconnecting the source of ringing current from the trunk circuit, means for thereafter energizing the signal control relay over the talking conductors, and means responsive to the energization of the bridged relay for closing thenormally open talking conductors. p

3. A telephone exchange system con1prising a trunk circuit extending from a first to a second switchboard, a link circuit at the first switchboard, a source of ringing current, means responsive to the connection of the link circuit with the trunk circuit ,for connecting the source ot ringing current therewith, a signaling device at the second switchboard, a relay energized upon the connection of the link circuit with the trunk circuit for operating thesignaling device, a link circuit at the second switchboard, a relay operating upon the connection of the second link circuit with the trunk circuit to denergize and connect the first relay in bridge of the talking conductors, and means in the, link circuit responsive to the connection of the first relay in bridge of the talking conductors for disconnecting the source of ringing current from the trunk circuit. V V

4:.oA telephone exchange system comprising a trunk circuit having normally open talking conductors extending from a first to a second switchboard, a link circuit at the first switchboard, a source of ringing current, means responsive to the connection of the link circuit with the trunk circuit for connecting, the source of ringing current therewith, a link circuit at the-second switchboard, a relay connected in bridge-of the talking conductors upon the-connection of the second link circuit with the trunk circuit, means in the first link circuit responsive to the connection of the relay in bridge of the talking conductors for disconnecting the source of ringing current from the trunk circuit, a source'of'direct current connected with the trunk circuit upon thedisconnection of the source of ringing current for en- 'ergizing the bridged relay, and a relayresponslve to the energ zatlonof the-bridged V relay for closing the normally open talking conductors.

5. A telephoneexchange system comprising a trunk circuit having normally open talking conductors extending from a first to a second switchboard, a link circuit at the first switchboard, a source of ringing-current, means responsive to the connection of the link circuit with the trunk circuit-for connecting therewith the source of ringing current, a signal control relay operating upon connection of the link circuit with'the trunk circuit, a link circuit at the second switchboard, a relay operating upon the connection of the second link circuit with the trunk circuit for releasing and connecting the signal control relay 1n bridge of the talklng conductors, means 111 theifirst' l nk circuit responsive to the connection of the of the talking conductor control. relay.

In witness whereof I hereunto subscribe my namethis 27th day of'April, A; D.- 1918.

o ERIC R; LUNDIUS.

7 Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. 0.": V V

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