US1522875A

US1522875A - Telephone-exchange system

Info

Publication number: US1522875A
Authority: US
Priority date: 1920-09-08
Publication date: 1925-01-13
Anticipated expiration: 1942-01-13
Also published as: US1470991A; DE401008C

Description

CL B. FOWLER TELEPHONE EXCHANGE SYSTEM Filed Sept. 8, 1920 2 Sheets-Sheet 1 c. B. FOWLER.

TELEPHONE EXCHANGE $YSTEM Filed Sept. 8, 1920 2 Sheets-Sheet 2 fi n 1' 5 Ta m- Z 1 1 N "a WW u.

Patented Jan. 13, 1925.

UNITED STATES PATENT OFFICE.

CLARENCE B. FOWLER, OF NEW YORK, N. Y., ASSIGNOR T WESTERN ELECTRIC COM- PANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEVT YORK.

TELEPHONE-EXCHANGE SYSTEM.

Application filed September 7 '0 all whom it may concern:

Be it known that I, CLARENCE B. FOWLER,

a citizen of the United States, residing at New York, in the county of New York and 6 State of New York, have invented certain new and useful Improvements in Telephone-lilxchange Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone exchange systems and more particularly to such systems in which connections between telephone lines terminating at manual exchanges and telephone lines terminating at automatic exchanges, are established by way of cord and trunk circuits over which automatic switches are controlled from the manual exchange for effecting connections.

The object of this invention is the production of improved talking and signaling circuits for a system of this nature and also to provide for complete supervision over the connections for the operator at the manual exchange.

One of the features of the invention consists in providing a repeating trunk circuit with capacity which may be reduced to a lixed minimum under the control of the 0pcrator to provide an efficient signaling circult during the establishment of a connection, and increased to a fixed maximum under the control of a called subscriber to provide an ellicient talking circuit.

Another feature of the invention consists in such an arrangement of circuits and apparatus that the called subscriber not only controls the varying of capacity to provide an eflicient talking circuit, but also controls means for furnishing the operator with f l complete supervision of the connection.

In the drawings Fig. 1 represents a circuit arrangement of a semi-automatic telephone exchange system embodying the invention, only so much being shown of the l5 circuits and apparatus as is necessary for a clear understanding of the present inventiou. Fig. 2 shows a modification of Fig. 1. There is shown in Fig. 1 of the drawings a telephone line A which terminates at the a: manual exchange where it may be connected with a cord circuit B in any suitable and well-known manner. The calling end of the cord circuit may be connected with a trunk circuit T extending from the manual to the 8, 1920. Serial No. 408,387.

automatic exchange, at which are provided the usual selector and connector switches for effecting connection between the trunk circuit and telephone lines, such as D, ter minating at the automatic exchange. The apparatus shown to the left of the dotted line 1-1 is located at the manual exchange and to the right thereof at the automatic exchange. The trunk circuit T comprises inner and outer sections normally inductively united by means of a large capacity condenser 14. A small capacity condenser is normally disconnected from the trunk circuit, but it may be connected to the trunk circuit under the control of the operator and disconnected from the trunk circuit un der the control of the called subscriber such as D.

Referring to Fig. 2 of the drawings there is shown a telephone line E which terminates at the manual exchange where it may be connected with a cord circuit F in any suitable and well-known manner. The calling end of the cord circuit F may be connected with a trunk circuit T extending from the manual to the automatic exchange. at which are provided the usual selector and connector switches for effecting connections between the trunk circuit and the telephone lines, such as G, terminating at the automatic exchange. The apparatus shown to the left of the dotted line 2-2 is located at the manual exchange and that to the right thereof at the automatic exchange. The trunk circuit T comprises inner and outer sections normally inductively united by means of large capacity condensers 121 and 124:. Small capacity condensers 122 and 123 are normally disconnected from the trunk circuit T but may be connected to the trunk circuit under the control of the operator and then disconnected therefrom under the con trol of the called subscriber.

The nature of the invention'is suchthat it is believed a clear understanding thereof may be had from the following detailed de scription and the appended claims.

Referring to Fig. 1 of the drawings and assuming that the subscriber at the station on the telephone line A has initiated a call, and that the answering end of the cord circuit 13 has been associated therewith in any well-known manner, the operator actuates listening he; 5 thereby connecting the operators telephone set (not shown) in circuit so that the operator may converse with the calling subscriber to ascertain the number of the line with which connection is desired. Ascertaining that connection is desired with telephone line D, which terminates at the automatic exchange, the operator inserts calling plug 6 of the cord circuit B into jack 7 of the trunk circuit T. Calling supervisory lamp 8 of the cord circuit B is lighted over a path extending from grounded battery, through lan l? 8,

resistance 10, sleeves otplug 6 andjack 7 and coil, 9 to ground. Relayf44 0i thetrunk circuit T operates over a circuit traceable 'lrom grounded rbattery, winding relay 44, left-handnormal contacts of relay- 46, tips of jack 7 and plug 6, upper normal contacts of relay 22, upper normal contacts or ringing key 42, and upper right-hand winding of repeating coil 50 to ground. The operation of relay 44 bridges polarized relay 13 in multiple with the non-inductive resistance 45 across the talking conductors oi the outer section of the trunkover a path traceable from conductor 60, through. the winding ofpolarized relay 13 in parallel with the back contact and armature of relay z-o and resistance 45 to conductor 61, "for he purpose of operating a non-numerical switch (not shown) at the automatic exchangeito extend the trunk T to an idle connector C. As soon as the connection is "tended to the connector C, line relay ereof is energized over a path extending from grounded battery, left-hand winding cl relay 35, outer normal contacts of relay so. conductor 61, front contact and armature of relay 44, through resistance and righthand armature and back contact of relay 46 in parallel with the winding of the polarized relay 13 to conductor 60, inner normal contacts of relay 36, and right-hand winding ot' relay 35 to ground. Polarized relay 13 does not operate at this time since the direction of flow of current through its windings is such as to prevent its operation.

The operator may now actuate the impulse sender S, which is common to the cord circuits of her position. Upon the initial actuation of the impulse sender S, the off normal contacts 21 thereof close, causing the operation of relay 25 which remains uptl'itliBCl during the transmission of each series of impulses. Relay 25 in operating, causes the operation of connecting relay 22 ot' the cord circuit B and switching relay '1 l otthe trunk circuit T over a circuit traceable from ground, armature and backcontact of relay 23, front contact and left hand armature of relay 25, outer lower contacts of key 5, lower normal contacts of key 42, inner lower normal contacts and winding of relay 22,, rings of plug 6 and jack 7, armature and back contact of polarized relay 18, and Winding of relay 11 to grounded battery. Relay 22 in operating locks up in series with relays 23 and 11 over a pathtraceable from ground, winding of relay 23, contacts of key 26, lower inner armature and front contact and winding of relay 22, rings of plug 6 and jack 7, armature and back contact of polarized relay 13 and winding of relay 11 to: grounded bat tery. The operation of relay 22 opens the talking conductors of the cord. circuit B and connects groundthrough the impulse contacts 20 of the sender S to relay 44 to hold said relay 44, which was previously energized, operated. the pilot relay 23 resulting from closure oi The energization of the locking circuit 01 relay 22, opens a contact in the original energizing circuit oi relay 22 and causes lamp 28 to be lighted indicating to the operator that the impulses sendcr S has been renderedindividual to the cord circuit and connected therewith. As soon as pilot lamp 28 lights the operator may restore key 5 to normal.

The operation of relay 11 disconnects the large capacitycondenser 14 from the talking conductors of the trunk circuit T and connects the small capacity condenser 15 there to, so that the large capacity condenser will not interfere with the transmission oi iuipulses and still provide a path for the trausmission oi? tones from the automatic exchange back to the calling subscriber as well as to the operator. Relay 22 ot the cord circuit and relay 11 of the trunk circuit after being operated remain locked up until released by the operator actuatin key 26 or until polarized relay 13 energizes upon the response of the called subscriber.

The opening and closing of the impulse contacts 20 of the sender S during the return movement of the sender to its normal position causesthe opening and closing of the circuit of impulse repeating relay 44. Each time relay 44 deenergizes in response to the opening of its circuit, the bridge across the outer section of the trunk circuit T willbe interrupted thereby causing the deenergization of impulse relay 35 of the connector C. The impulse relay of the connector controls the usual motor magnets tor the connector whereby the brushes 38 and 39 oi? the connector are set upon the terminals and iii of the telephone line D. The subscriber at station l) may be signaled in a manner well known in the art.

Tones,indicating to the calling subscriber that a station is being signaled or in case the calling line D had been busy and a source of busy tone had been connected to the trunk conductors and (S1 in any manner well known in the art will be trans mitted to the calling subscriber or to the operator even though the talking conductors of the trunk and cord. circuit are opened, over a path traceable from conductor 61 through the trout contact and armature of relay a l, lower alternate contacts of relay 11, small capacity condenser 15 rings of jack 7 and plug 6, condenser l lower normal contacts of ringing key 42, and thence to the operators telephone set or through the winding of supervisory relay 4i and lower right-hand winding of repeating coil to grounded battery. The tone passing through the secondary winding of repeating coil 50 is induced into the primary winding thereof and passes through supervisory relay 56 over the line loop of line A to the subscriber therealx The operator and. the calling subscriber are thus supplied with a path for the reception of tones from the distant exchange. which is independent of the normal tz'ilking conductors extending from said subscriber to said distant exchange.

The subscriber of telephone'line D in responding to the calling signal causes the energization of reversing relay 36. The enen gization of relay 3(3 reverses the battery con llQClllOl'iS of the talking conductors of the trunk circuit whereby polarized relay 13, bridged across the outer section of the trunk circuit '1, is energized and opens its back contact. The opening of this contact interrupts the locking circuit ol relays 23, 22 and 11. whereupon these relays deenergize. The deenergization of relay 2 opens the circuit of and extinguishes pilot lamp 28; the deenergization of relay 22 disconnects the sender S from the cord circuit B, renders the talking conductors of the cord circuit continuous, and short-circuits condenser l; and the deenergization of relay ll disconnects the small capacity condenser 15 front and connects the large capacity condenser l4: to the talking conductors of the trunk circuit T.

The energization of polarized relay 13 also bridges relay 46 across the talking conductors of the inner section of the trunk thereby causing the operation of supervisory relay ll. of the cord circuit B over a circuit traceable from ground, upper righthand winding of repeating coil 50, upper nori'i'ial contacts of relay 22, tips of plug 6 and jack '7, winding of relay 46, front contact and armature of polarized relay l3, rings of jack 7 and plug 6, back contact and lower outer armature of relay 22, lower normal contacts of ringing key 42, winding of supervisory relay ll, and lower right-hand winding of repeating coil 50 to grounded battery. Relay 41 in energizing shunts supervisory lamp 8, thereby causing the ex tinguishing oi? said lamp, which indicates to the operatorthat the called party has responded.

Relay 4:6 is energized over the circuit ust traced and in attracting its left-hand armature, substitutes a local ground for main taining impulse responsive relay lt in place of the ground at the contacts 20 of impulse sender S, and in attracting its right-hand armature removes the non-inductive resistance l5 from parallel relationship with the winding of poralized relay 13.

Prior to the response of the called subscriber at the telephone line D, the operator may tree the impulse sender S from connection with the cord circuit B by actuating key 20. Opening of the contacts of the key 26 interrupts the locking circuit for relays 23, 22 and 11 in the manner be'tore described, thereby disconnecting the sender S from the cord circuit; rendering the talking conductors of the cord circuit continuous;

substituting the small for the large capacity condenser; and extinguishing pilot lamp 28. If, after the operator actuates the key 26, the subscriber of station D responds by removing the receiver from the switchhook, the energization of reversii'ig relay 36 causes the operation of polarized relay 13. The operation of relay l3 bridges relay l6 across the talking conductors of the inner section of the trunk, whereupon supervisory relay ll-l energizes thereby extinguishing the supervisory lamp 8.

At the conclusion of conversation the subscribers restore their receivers to the switchhooks. The restoration of the receiver to the switchhook at the station on the elephone line D, causes the deenergization of reversing relay 36, whereupon the connection of battery and ground with the talking conductors of the trunk circuit is reversed causing the release of polarized relay 13. Relay 4:6 is removed from bridged relation with the talking conductors otthe inner section of the trunk and supervisory relay ll deener-' gizes, permitting the lighting of the supervisory lamp 8 which now serves as a disconnect signal to the operator at the manual otlice. The operator may thereupon (llSCOTlnect the plug 6 from the jack 7 whereupon all apparatus associated with the calling end of the cord circuit 8 of the trunk circuit T is released and restored to normal position, thereby releasing the switches at the automatic exchange.

Referring tOl Fig. 2 of the drawings and assuming that the subscriber at telephone line E has initiated a call and the answering end of the cord circuit F has been asso ciated therewith in any \-:ell-knov.u'i manner, the operator actuates a listening key (not shown) thereby connecting the operators telephone set (not shown) in circuit so that the operator may converse with the calling subscriber to ascertain the number of the line with which connection is desired. Assuming that connection is desired with telephone line (i. the operator may restore the key to normal and then insert calling plug 106 of the cordcircuit F into jack 107 of the trunk circuit T Relay 11.5 01 the cord cir cuit 1* and sleeve relay 120 of the trunk circuit T are thereupon energized over a path extending from grounded battery, through the winding of relay 115, winding of marginal relay 112 which is not energized at this time, normal contacts of relay 114:, sleeves of ph'ig 106 and jack 107 and winding of relay 120 to "ground. Relay 115 in operating disconnects the usual test lead to the ope "ators telephone set from the tip of the cord circuit "and renders the talking 'conductors'oi' the cordcirtuit conti'iuious. Relay 1.12 is ot the in'argi'naltype and does not operate in series "with relay 120, whichhas a high resistance armature of relay 126.

' winding.

'l'ni 'iedance coils 1'09 and 11.0 there'tore remain bridged across the talking conductors of the cord when a connection established with the trunk circuit 1. "he particular cord circuit herein shown adaptable for use with other trunk circuits which do nothave a resistance such as the winding of relay 120 connected to the sleeve 01 the ack in which case, the marginal relay 112 operates thereby disconnecting the impedance coils 109 and from bridged relationship with the cord circuit. Relay in operating establishes a circuit for the 'energiz ation 0t slow-to-release relay 118 over a path extending from grounded battery, through the inner armature and front contact of relay 120 and through the windingot relay 118 to ground. Relay 120 in operating also bridges the winding of polarized relay 126 across the outer section of the trunk thereby causing the operation of a non-numerical switch (not shown) at the automatic exchange for the purpose of extending the trunk to an idle connector switch such as K at the automatic exchange.

Impulses relay 128 at the connector K thereupon operates over a path extending from grounded battery, left-hand winding of relay 128, outer left-hand normal contacts of relay 129, conductor 131, outer right-hand armature and front contact of relay 120, winding of polarized relay 126, conductor 130. inner normal contacts of relay 129 and right-hand winding of relay 128 to ground. Polarized relay 128 does not operate at this time since the direction of flow of current through its winding is such as to prevent its operation.

The operation of slow-to-release relay 118 causes the operation of relays 116 and over a path extending from grounded battery, left-hand armature and front contact of relay 118, windings of relay 11.6 and 125 in parallel to ground at the baclrcontact and Relays 116 and 125 in operating disconnect the large capacity condensers 121 and 1.211 from the tip and ring talking conductors of the trunk circuit T respectively, andconnect the small capacity condensers 122 and 123 thereto. Relay 116 in operating also connects ground and battery to the tip and ring talking conductors of the inner section of the trunk circuit T respectively, thereby causing the operation of supervisory relay 108 of the cord circuit over a path extending from ground, left-hand winding of retardation coil 117, upper alternate contacts o't relay 116, tips 01 jack 107 and plug 106, arn'iature and trout contact-of relay 115, coil 110, baclr contact and armature ofrelay 112, winding of relay 108, coil 109, rings ofplug 106 and jack 107, lower alternate contacts 01 relay 116, and rightdiand winding ofre-tardatiou coil 117 to grounded-battery. Rtelay 1.08 in operating completes a circuit at its arinature and front contact tor the lighting of supervisory lamp 111. Relay 125 ol the trunk circuit T in operating bridges non-- inductive resistance 12'? across the outer section of the trunk in parallel with the winding of polarized relay 1267 The operator may now actuate the monitoring and dialing key 105, which is pro vided for each of the cord circuits, 1 in addition to the listening key therefor, heretot'ore referred to upon actuation of key 105, relay 11s v is energized over a path extending from ground, through contacts 101 ct 'ey 105 and, winding of relay 11st to ground d battery. "lelay 1141, in operating, coiniecls the impulse sender S to the sleeve the cord circuit through its inner armature and front contact and connects ground thro gh resistance 113 at its outer armature and t: out contact to

relays

112 and 115 in order to hold relay 115 energized.

The operator may now actuate the inipulse sender S in order to set the brushes oi switch K upon the terminals of the desired telephone line G. Each interruption of the contacts 1-10 of the impulse sender s causes the release of repeating relay 120 oi the trunk circuit T which in retracting its armatures opens the bridge across the outer section of the trunk, thereby releasing impulse responsive relay 128 of the coimector K. Relay 118 being slow-to-release does not retract its armature during the seiuling of a series of impulses and relays 11.6 and are tl'iereli y maintained energized. The impulse responsive relay 128 of the connector switch K controls the usual motor magnets for the connector at the automatic exchange under the control of which the

brushes

138 and 139 of the connector K are set upon the terminals and 151 of the telephone line G. The call hell at the station of telephone line G may be actuated in the usual nianner'and the subscriber in. responding to the operation thereof, removes the re ceiyer "from the switchhook causing the energization of reversing relay 129. The enerill) lilu

gizat-ion of relay 129 reverses the battery connections to the talking conductors oi the trunk circuit, whereby polarized relay 126, bridged. across the talking conductors of the trunk circuit T is energized and opens its contact. The opening of this contact interrupts the locking circuits for

relays

116 and 125.

Relays

116 and 125 thereupon release. Relay 116 in retracting its armatures renders the talking conductors of the trunk circuit T continuous, thereby disconnecting the small oapa city condensers from the trunk circuit and connecting the large capacity condensers 121 and 124lthereto. Relay 116 in retracting its armatures also disconnects ground and battery from the tip and ring talking conductors of the inner section 01 the trunk circuit T thereby causing the release of supervisory relay 108 of the cord circuit- F and the consequent extinguishing of the supervisory lamp 111, which indicates to the operator that the called party has responded. Relay 125 in releasing removes the non-inductive resistance 127 from parallel relationship with the winding of polarized relay 126 and disconnects the small capacity condensers 122 and 123 from the talking conductors of the outer section of the trunk circuit- T Up until the time that the called subscriber of telephone line G responds, a path for tones, such as a busy signal tone 0 a ringing signal tone exists over the trunk circuit '1 and the connected cord circuit F for the operator and the calling subscriber or the telephone line E over a path traceable from conductor 131, through the lower armature and front contact of relay 125, condenser 123, lower alternate contacts of relay 116, rings of jack l0? and plug 106 and thence through the calling substation loop or the operators telephone set, to the front contact and armature of relay 115, tips of plug 106 and jack 107, upper alternate contacts of relay 116, condenser 127, upper alternate contacts of relay 125 to conductor 130. The operator and subscriber are thus supplied with a path for the reception of tones from the distant exchangewhich is independent of the normal talking circuits extending from said subscriber to said. distant ex change.

At the conclusion of conversation the subscribers restore their receivers to the switchbooks. The restoration of the receiver to the switchhook at the station of telephone line G causes the deenergization of reversing relay 129, whereupon the connections of battery and ground with the talking conductors of the trunk circuit are reversed causing the release of polarized relay 126. Relay 126 in deenergizing again completes a circuit for

relays

116 and 125 over paths previously traced. Relay 116 in operating connects ground and battery to the talking conductors of the trunk circuit, thereby causing the energization of relay 108 as before described and the consequent lighting of supervisory lamp 111, which now serves as a disconnect signal to the operator at the manual oilice. The operator will thereupon disconnect the plug 106 from the jack 107, whereupon all apparatus associated with the calling end of the cord circuit F and with the trunk circuit T is released and restored to normal position. Opening of the bridge across the outer section of the trunk circuit T causes the release of the switch at the automatic exchange.

What is claimed is:

1. In a telephone exchange system, a called line, an operators cord circuit, a trunk circuit and automatic switches for estahlishing a connection with said line, capacity in said trunk circuit, a supervisory signal in said cord circuit, means controlled by the operator i or varying said capacity, and

ieans controlled by the called line for varying said capacity and for actuating said signal.

2. In a telephone exchange system, a 02.11 ing line at a manual exchange, a called line at an automatic exchange, means including an operators cord circuit, a trunk circuit and automatic switches for establishing a connection between said lines, capacity for said trunk circuit, and means controlled by the operatorand the subscriber of the called line for varying said capacity.

3. In a telephone exchange system, a called line, a trunk circuit, means including an impulse sender and automatic switches for establishing a connection over said trunk circuit with said line, capacity in said trunk circuit, means responsive to the actuation ol the impulse sender for varying said capacity and means controlled by the called line for varying said capacity.

4:. In a telephone exchange system, a trunk circuit, a cord circuit connected therewith, an impulse sender, means responsive to the actuation of said sender for connecting it with the cord circuit. capacity in said trunk circuit, a telephone line, and a relay in said trunk circuit for varying said capacity and for causing the disconnection of said sender from said cord circuit, said relay being con trolled by said telephone line.

5. In a telephone exchange system, a trunk circuit, a cord circuit connected therewith, an impulse sender, means responsive to the actuation of said sender for connecting it with the cord circuit, a telephone line, a supervisory signal in said circuit, capacity in said trunk circuit, and means controlled by said telephone line for disconnecting said sender from said cord circuit, actuating said supervisory signal and varying said capacity.

6. In a telephone exchange system, a Cord circuit, a called line, means including a twoconductor trunk circuit for establishing a connection to said called line, a large capacity condenser normally connected in said trunk circuit, a small capacity condenser normally discoi'inected from said trunk circuit, means controlled by said sender for substituting the small for the large capacity coi'idenser, and means controlled by said called line for substituting the small for the large capacity condenser.

T. in. a telephone system, a calling line, a called line, means including an operators cord circuit, a repeating trunk circuit having inner and outer sections and automatic switches for establishing a connection be tween said lines, an impulse sender for said cord circuit, condensers of large capacity normally connecting the inner and outer sections of said trunk circuit, small capacity condensers normally disconnected li'rom the inner and outer sections of said trunk circuit, operator controlled means for disconnecting said large capacity condensers from said trunk circuit and substituting therefor said small capacity condensers, and means controlled by saidcalled line for disconnecting said small capacity condensers and substituting said large capacity condensers therefor.

S. In a telephone system, a calling station, a called station, means including a link circult and a trunk circuit for interconnecting said stations, capacity in said trunk circuit, means responsive to the connection of the link circuit With the trunk circuit for varying the capacity of the trunk circuit, and means controlled by the called subscriber for varying the capacity of the trunk circuit.

5,). In a telephone system, a calling station, a called station, means including a cord circuit terniinating in a plug and a trunk circuit terminating in a jack for interconnccting saii'd stat-ions, capacity in said trunk circuit, means responsive to the connection 01 the plug of the cord circuit With the jack oi the trunk circuit for varying the capacity of the trunk circuit, and means automatically operating in response to the answering ot the called subscriber to again Vary the capacity oi the trunk circuit.

In witness whereof, I hereunto subscribe my name this26th day of August, A. D., 1920.

CLARENCE B. FOWLER.