US1533192A - Telephone-exchange system - Google Patents

Description

April 14,-1925.

' C. W. KECKLER TELEPHONE EXCHANGE SYSTEM .Filed Dec. 6. 1919 Patented Apr. 14, 1925.

UNITED STATES PATENT OFFICE.

CHARLES W. KECKLER, 0F NEWARK, NEW JERSEY, ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

' TELEPHONE-EXCHANGE SYSTEM.

Application filed December 6, 1919.

To all whom it may concern:

Be it known that 1, CHARLES W. KEGKLER, a citizen of the United States, residing at Newark. in the county of Essex, State of New Jersey, have invented certain new, and use ful Improvements in Telephone-Exchange Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone ex change systems and more particularly to cir- I cuit arrangements at a manual private branch exchange where such an exchange is employed in connection with a main exchange of thecommonbattery type. I

An object of the invention is to provide improved signaling means for such systems,

and to. avoid the tying up of trunks extending between the private branch exchange and the distant exchange in cases of slow disconnect on the part of the operator. I I Another object of the invention is to pro- .vide for instantaneous recall on the part of the subscriber at the private branch exchange or the distantoffice.

A further object of thein'vention is to )revent ringing current from falsely signaling the connected subscriber at the private branch exchange in cases of a second call from thedistant oflice for the private branch exchange prior to disconnection by the operator. I I I I I In the present embodiment of the invention the circuit arrangements are such that the, subscriber at the private branch exchange controls the release of a trunk lead- I ing to the dist-ant o-ifice.

More specifically restoration of ther CQlVGlftO, the switchhook ofthesubscriber at. the private branch exchange, after completion of conversation with a subscriber at the distant office, opens the line loop thereby causing a supervisory lamp to be actuated and the automatic switches at a distant oflice to be-Teleased. Restoration of the receiver alsocausesaswitching relay in the'trunk circuit at the private branch exchange to operate thereby connecting the line. signal to the trunk and opening up the trunk conductors, which-enables the operator to again be signaled over said trunk and prevents ringing current from passing to the con- Serial No. 343,003.

nected station in case of a slow disconnect.

A further feature is the provision of means whereby, prior to disconnecting by the operator, the subscriber at the private branch exchange may either signal the operator indicating that a connection with another station of the private branch exchange is desired or he may without the aid of the operator call a subscriber at the distant oflice, in the latter case a supervisory relay being actuated at the private branch exchange thus indicating to the operator thereat that the line and trunk connected thereto are busy.

For a more complete understanding of this invention reference should be had to the I following description and to the accompanying drawing which illustrates one embodiment thereof. Vhile the invention is shown in connection with an automatic exchange, obviously it could be employed with a manual common battery exchange.

There is shown in the drawing a telephone line A terminating in an automatic exchange. By meansof an impulse sender S and automatic switching apparatus, such as a line finder F, selector L and connector C, diagrammatically indicated, the subscriber A may select a trunk. such as T extending from the automatic exchange to the manual private branch exchange. The apparatus shown to the left of the dotted line OO is located at the automatic exchange and that to the right thereof at the manual exchange. At the manual exchange, a signaling means, a switching relay and a jack in which the trunk terminates are provided. By means of the link circuit B the calling line A may be extended to any station such as D terminating in a jack at the private branch exchange. I I

The nature of this invention is such that it is believed that a clear understanding thereof will be obtained from a description of the operation of the system shown in the drawing. and it will be so described.

Itwill be assumed that a subscriber at substation A in the automatic exchange desires a connection with a subscriber D terminating in a manual exchange. The subscriber at substation A will therefore re-v ner and ringing current is sent over the.

conductors 12, 13 of the trunk T to the manual exchange to actuate a signal thereat, the path therefor beingas follows: ground, third contact of side switch and its brush 10, conductor 12, outer left-hand armature and back contact 'of relay 21, lefthand winding of relay 22, condenser 23,

. conductor 13, side switch brush 11 and its third contact, winding of relay 24, and armature. and front contact of relay 25, (which is energized in position 3 of the side switch brushes) to source of ringing current 26. Relay 22, upon'energization establishes alocking circuit for itself including itsright-hand winding, front contact and armature and the back contact and inner left-hand armature of relay 21 and also com- 1 pletes a circuit for the line si nal 20 from battery, lamp 20, front contact and armature of relay 22 andback contact and inner left-handarmature of relay 21 to ground.

In response to the signal, the operator inserts the plug 28 of the link circuit '15 into jack29 of the trunk circuit T. Relay 21 of the trunk circuit T and relay 30 of the link circuit B are thereupon energized over a circuit from grounded battery, winding of relay, 21. sleeves ofv jack 29 and plug 28, left-hand normal contact of relay 31 and winding of relay 30 to ground. Relay- 21 in energizing disconnects the ringing relay 22. from the trunk circuit and interrupts the I circuit for the lamp 20 at its left-hand armatures and at its right-hand armatures connects the trunk circuit through to, the link circuit B. Relay 30 of the link circuit B at. its inner left-hand armature and front contact completes a bridging circuit, including the left-hand inner armature and back contact of relay 44 and the wi'dings' 32 and 33 of a retardation coil, across the talking conductors of the cord circuit thereby caus- 1 ingringing relay 24 in the connector circuit G to energize to trip the machine, ringing andmove the side switch brushes of the conneotorinto position 4 in the manner well known.

The operator thenactuates the listening key 35 thus connecting her telephone set (not shown) incircuitv so that she may converse with the calling subscriber, and having as certained that station D is desired, the operator inserts calling plug 40 of the link circuit into jack 41, in which the line leading to station D terminates.- Supervisory lamp 42 lights and the line cut-off relay 43 is energized over a circuit extending from grounded battery, lamp 42, back contact and right-hand armature of relay 44, back contact and armature of supervisory relay 45, sleeves of plug 40 and jack 41 and winding of relay 43 to ground; The operator will then actuate ringing key 46 of the link circuit 13 to signalstation D in the usual manner.

Upon response of the called subscriber, a

path for the talking current for station D may be traced as follows: ground, left-hand winding of relay 5 of the connector C, side switch brush 10 in its fourth position, conductor 12, front contact and outer righthand armature of relay 21, tip of jack 29 and of plug 28, upper normal contacts of ringing key 50, right-hand normal contacts lower normal contacts of. ringing. key 50,

ringof plug 28, ring of jack 29, right-hand inner armature and. front contact of relay 21, conductor 13, side switch brush 1.1 in its fourth position, and right-hand winding of relay 5 of the connector C to grounded battery. Suflicient current. flows through supervisory relay 45 to cause its energization although up until the time that relay 45 is energized, the retardation coil windings are bridged across the link circuit. Relay 45 attracts its armature and in so doing causes the supervisory lamp 42 to befextinguished and the holding bridge across the talking conductors of the link circuit B to be disabled. Relay 44, which interruptstlie holding bridge at its inner left-hand ar'ma ture and back contact, is energized over the following paths: grounded battery, outer. left-hand armature and front contact of relay 30,. winding of relay 44, front contact and armature of relay 45, sleeve of plug 40, sleeve of jack 41, and winding of relay 43 to ground. Relay 44 is he'ldlocked up through its outer left-hand armature and front contact and the normal contact of listeningkey 35 through resistance coil 27, to ground. p

At the conclusion of conversation subscriber D restores the receiver to. the switchhook, thus opening up the loop for relay 5 of the connectorswitch C, which will cause the restoration of the switches in the automatic exchange in the manner well known. Trunk circuit T may then be selected by another connector causing trunk signal 20 to light even though the plug. 28 is not removed from jack 29 immediately, as in the case of a slow disconnect, in a manner hereinafter described; TSupervisory relay 45' is deenergized upon the restoration of thereceiver of station D to its switchh'ook, thereby causing energization of relay 31 over a path extending from grounded battery, winding of relay 3l, front contact and right-handarmature of relay 44, back-contact and armature of supervisory relay 45., sleeve of plug 40, sleeve of jack 41, and winding of relay 43 to ground. Relay 31, upon energization, establishes at itsrighthand armature and front contact a circuit for supervisory lamp 42 causing it to light to indicate to the operator that conversation is completed. At the left-hand armature and normal contact of relay 31, the circuit for relay 21 is interrupted, thus opening up the talking conductors of the trunk T, and again bridging the ringing relay .22 across the trunk. 1

In case another call comes in over'the trunk from. the ..aut0matic exchange, before the operator has disconnected, ringing relay 22 will again be energized causing the line signal to light. Ringing current'will be prevented from passing through to the stationD since the talking conductors of the trunk are open at the contacts of relay 21. VVhenrelay-31 was energized a circuit for relay 30 was maintained though grounded battery, resistance 60, and the left alternate contacts of relay 31, which are of themakebefore-break type. i i

Assuming that a second 'call has arrived over the trunk circuit T, relay 22 will be energized as heretofore described and-the trunk lamp 20 will light. The operator observing the signal actuates'listening key 35 and in so doing interrupts at its normal contact the locking circuit for relay 44. Relay 44, uponv deenergization, interrupts at its right-hand armature and contact, the circuit for relay 31 and at its inner left-hand armature and back contact restores the bridge across the talking conductors of link circuit B. Relay 31 in deenergizing again completes a circuit at its left-hand armature and normal contacts for relay 21,'which,

upon energization, disconnects ringing relay 22 and signal 20 from the trunk circuit B, and reestablishes the continuity ofthe talkingconductors of the trunk circuit. The bridge across the link circuit B tripsthe machine ringing as before and causes the side switch brushesto move from position 3 to p0sition4, thus enabling the operator to converse with the calling subscriber, In case substation D is again desired, the operator actuates the ringing key 46 to signal station D,-or-. in' case some other station is desired, plug 40 is removed fro1n..jack. 41

and inserted in:,the jack in which the desired line terminates. Upon completion of conuver'sation supervisory lamp42 lights, as before described, whereupon the operator removes the plugs from their associated jacks and all relays are restored to normal.

Assume that substation D desires to make a call or gain the attention of the operator prior to disconnection. The supervisory lamp 42 of the cord circuit maybe flashed in responseito actuations of the switchhook at station D. Removal of the receiver at station D prior to disconnection, causes energization ofsupervisory relay 45 over the following'path: ground, resistance 16 of the trunk circuit T, tip of jack 2!) and of plug 28, upper normal contacts of ringing key 50, right-hand normal contacts of. dialing key 51, upper normal contacts of ringing key 46, tip of plug 40 and of jack 41 over the loop of station 1), ring of jack 41 and of plug 40, lower. normal contacts of ringing key 46, inductive winding of supervisory relay 45 and non-inductive winding 52 thereof, and right-hand armature and front contact 'ofrelay 30 in parallel, left-hand normal contacts of dialing key 51, lower normal contacts of ringing key 50, ring of plug 28 and of jack 29, inner right-hand armature and back contact of relay 21, and

resistance 15 to grounded battery. Attraction of the armature of. relay 45 interrupts the circuit for supervisory lamp 42. The operator noting the supervisory signal actuates listening key 35 and converses with station D, and in case another station at the manualexchange is desired, plug 28 will he removed from jack 29 and inserted in the jack. to which the desired line is connected.

Supposing on the other hand that prior to disconnection station D desires to dial a subscriber at the: automatic exchange. 11 will be remembered that prior to removal of plugs 28 and 40 from their associated iacks, and after the-subscriber at station D has hung up, relays 21 and 45 are deenergized and relays 30, 44 and 31 are ener ized. Removal-of the receiver atstation D from the switchhook energizes supervisory relay. 15, which attracts its armature. thereby interrupting atits hack contact the circuit for lamp 42 causing it tobe extinguished and indicating to the operator that the cord cir-. cnit is in use. w Attraction of the armature of relay 45 also interri'lpted at the back contact thereof; the circuit for relay 31 causing it to deenergize. Deenergization of relay 31 reestablishes at its left-hand armature and normal-contact, the circuit for relay 21. causing the latter to energize,.thus extending the line of station D over the trunk circuit T .to' the automatic exchange, wlrere the trunk terminatingat the connector C may be multiplied togthe 'line or trunk finder schematically represented onthe drawing by the rectangle X.- The. subscriber at station D may now actuatehis dial E to select the number desired in the manner well-known.

With each interruption in the linecircuit' of station-D, relay will deenergizeand at its armature and back contact close a" circuit for relay 31. This relay" is of theslow-to-operate type, however, and will not follow-the interruptions in; the: .line circuit; To indi cate that-relay 3l=is of the. slow' topperate type, arrows: pointing ini the'direction in which the armatures slowlymove are shown on the drawing.

Upon completion "of conversation, restoration to the switchhook-lof the receiver? at" sta tion D will open the line circuit, cause deenergizationof supervisory" relay 45 and the lighting of lamp 42, Armature of relay +5 in retracting again completes the circuit for relay 31-, which, upon energizing; interrupts the circuit for relay 21 therebyagain connectin g the alternating current bridge across the trunk and interrupting the continuity of the trunk conductors; The operator, noting' that the supervisory signal 4-2- is lit, will removethe plugs from their associated jacks, and all relayswill be restored to-normal;

A calling dial 61 is provided for the cord circuit by means of which the operator may select forthe calling-subscriber D, a line terminating in the-automatic exchange. Resistances 62and 63 connectedto battery and ground, respectively, supply current to the line of subscriber I.) when dialing key 51 is actuated, so'that' the subscriber may still control the supervisory signal. Since such arrangements-are well known and this forms no part of the present invention, a description of such anoperation is deemedunnecessary.

What is claimed is:-

1. In a telephone exchange-system, aman'- ual switchboard, a trunk line" including a pair of normallydiscontinuoustalking (onductors terminating thereat, an: alternating current bridge normally connected-to" said talking conductors, a subscribers line terminating at" said switchboard, a link i circuit for connecting-said trunkline'to said subscribers' line, a relay in said trunkcircuit adapteduponenergization to interrupt said alternating current bridge and establish" the continuity of said'talking conductor-s, means under'thecontrol of the operatonfor ener gizing said relay, and means-under the con trol of the subscriber for deenergizing'said relay. 7

2. Ina telephone exchange system, an automatic telephone: exchange, callingsub scribersline terminating thereat, a manual telephone exchange, a calledisubscribefls line terminating thereat, means including automatic switches and a trunk circuit for extending connection from c said calling to said called line, a-link circuit at saidmanual exchange forextendingsaid calling to said calledline, signaling means associated with said trunk circuit, means u'nd'er the control of the operator for dlsconnectmg and reconnecting; said signaling means tonsaidcontinuity of the talking conductors of said trunk circuit and to disconnect said signaling. means, and upondeenergization to restore said: trunk and said signaling means to normal condition, a" subseribersline, a link circuit for connecting said' trunk cir cuit with said subscribers line' and means controlled by the subscriber for energizing or deenergizing said switching relay;-

4'; In a-telephone exchange system,-aman-' ual exchange, a subscribers line terminating at saidmanualexchange, a trunk circuit extending to an automatic exchange terminatingzat said manual exchange, a link circuit at said manual exchangefor completing a-connectionreceived from said automatic exchange for a subscriber at said manual exchange, and meanscontrolled by'the subscriberat said manual exchange-for rendering; the trunk selectable immediately upon completion of conversation:

5: In combination with a trunk circuit and acord circuit for extending a call from a subscriber-at an automatic-exchange to a subscriber at a manual exchange, means whereby when the called subscriber at the manual exchange hangs upnfter completion of" conversation, the'trunk-circuit is available for arecall or asecond call over said trunk.

'6. In a telephone exchange system, an automaticexchange, a calling .subscribers line terminating thereat, a manual exchange, a called -subscriberis line terminatingithereat, meansincluding a: trunk line for extending said calling: line to said. mamialxexchange, a: link circuit at said manual exchange for-extending" said trunk line to said =c'al1ed' line, means under the con trol of'the calledisubscriber; for releasing the switches at said automatic exchange, and means: whereby the" called subscriber may immediately "after having releasedsaid switches; initiate a call over said link circuit and saidtrunk circuit for an automatic subscriber without the aid of theopera tor.

7.111 a telephone exchange system, an automatic exchange, a calling subscriber s line teri'ninatingthereat, a manual exchange, a called subscribers line terminating thereat, means including a trunk circuit for extending a call from said calling subscriber to said manual exchange, a link circuit at said manual exchange for extending said trunk circuit to said called line, means under the control of the called subscriber for releasing the switches at said automatic exchange, means for enabling the called subscriber to initiate a call for a subscriber at said automatic exchange immediately after having released the switches, and supervisory means in the link circuit actuated in response to the initiation of said call for indicating to the operator that said link circuit is in use.

8. In a telephone exchange system, an automatic telephone exchange, a calling subscribers line terminating thereat, a manual telephone exchange, a called subscribers line terminating thereat, a trunk circuit extending between the two exchanges, switching apparatus controlling the continuity of the trunk line and a line signaling device associated with said trunk circuit at the manual exchange, the signaling device responding to a call initiated by the calling subscriber, a

link circuit at the manual exchange for connecting said trunk to the line of the called subscriber, means for disabling the signaling device and for actuating the switching apparatus to receive the incoming call upon the connection of the link circuit with the trunk circuit, means controlled by the called subscriber for restoring said switching apparatus and the signaling device to normal association with said trunk circuit, said signaling device being in readiness to be again actuated upon a second incoming call over the trunk circuit from the automatic exchange, and operator-controlled means for again disabling the signaling device and for actuating the switching apparatus for the receiving of a second call While maintaining the original connection of said link circuit with said trunk circuit.

In witness whereof, I hereunto subscribe my name this 3rd day of December A. D., 1919.

CHARLES W. KECKLER.

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