US1230564A - Telephone-exchange system. - Google Patents

Description

UNITED STATES PATENT OFFICE.

HENRY P. CLAUSEN, OF MOUNT VERNON, NEW YORK, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO WESTERN ELECTRIC COMPANY, INCORPORATED, A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Specification of Letters Patent.

Patented June 19, 1917.

Application filed December 12, 1914. Serial Non 876,795.-

To all whom it may concern:

Be it known that I, HENRY P. CLAUSE-N, a citizen of the United States, residing at Mount Vernon, in the county of Westchester and State of New York, have invented certain new and useful Improvements in Telephone-Exchange Systems, of which the telephone systems, particularly ofthe me-;

tallic circuit and central energy types.

One of the objects of this invention is to provide an improved means whereby a oentral oiiice operator may efl'ect the automatic connection of a busy signal to a calling subscribers line with a minimum amount of labor and time. This may be accomplished by an electromagnetic means associated with a link circuit at the central oiiice, and under the control of the operator.v

Another object is the provision of means whereby the application of a busy signal to a calling subscribers line is delayed until the lapse of a predetermined time. This means may comprise quick and slow acting electromagnetic devices, which devices conjointly control the application of the busy signal to a calling line.

A further object is to provide means making it possible for a calling subscriber to maintain control of his line circuit in such a manner that he may effect the disconnection of the busy signal from his line and recall the operator without the removal by the operator of her answering cord plug from the subscribers line jack. This may be accomplished by electromagnetic-means associated with the operators link circuit and under the control of the subscriber.

The accompanying drawing illustrates diagrammatically one of the arrangements by which this invention may be eflectuated.

The subscribers stations Aand B, here shown equipped with the usual telephone apparatus well lmown in the art, are con: nected by means of line wires 1, 2 to a line jack 3 at the central oflice. Included in the line circuit is a line relay 4, which in pullingup its armature when energized by the removal of the receiver from the switch hook at the substation, lights a line lamp 5. Associated with the line jack 3 is a cutoff relay 6, which becomes energized when the operator inserts the answering plug of her cord circuit into'the jack in response to a call. At the central oflice there is provided the customary apparatus for connectlng two subscriberslines together, which apparatus in accordance with well known practlce, comprises an answering and calling plug 7 and 8, respectively; an operators set 19- which may be connected with the cord circuit-by means of a listening key 20, and a source of operating battery. Included 1n the sleeve strands of the cord circuit are supervlsory lamps 9, 9, having one side connected to battery and the other going to ground through the coil of the cut-off relays 7 and 8 are inserted 6, when the cord plugs in the line jacks 3. Bridged across the tip and ring strands of the cord circuit are relays 10 and 11, which are energized whenever plugs? and 8, respectively, are connected to the line jacks 3 and the receiver is removed from the switchhook' at the substation.

The-relays 10 and 11 control the operation of the supervisory lamps 9, 9, and the relay 10, in addition, controls a circuit of a locking relay 12. The relay 12 is of a type slow in responding and its operation will be hereinafter fully described. A busy signal 13, which is here conventionally represented, is adapted to be inductively connected to a calling subscribers line by the conjoint action of the relays 12 and 14:, the latter of which is associated with the operators set and adapted to be energized over the tipstrand of the calling plug 8,

when the operator makes a busy test of a called line in the usual manner, as will be hereinafter fully set forth. The relay '14 may be common to the various cord circuits of'an operators position as here illustrated, or if desired, an individual relay may be provided for each cord'circuit.

.As shown in the drawing, a source of ringing current is adapted to be applied to the called subscribers line in a manner well lmown in the art. In the-arrangement shown, provision is made for selective ringing, which maybe accomplished by the operator pushing any one of the four ringing keys 16 to a way-down position, causing contact 17 to be closed. The closure of contact 17 completes a circuit through the ringing relay 18, which relay effects the application of ringing current to the called subscribers line until its energizing circuit is interrupted by the removal of the receiver from the switch hook when the called party answers, which operation will be hereinafter described in detail. In event the operator inadvertently plugs in on a subscribers line already in use, to prevent either the calling or the called subscriber from receiving the busy signal, a guard relay 21 is provided which is adapted, upon energization to open circuit the locking relay 12.

The operation of the system thus described is as follows: Suppose that subscriber A. wishes to call subscriber B. Upon the re moval of the receiver from the switch hook at substation A the line relay 4 is energized, which in pulling up its armature closes contact 22, thus completing a circuit for the line lamp 5. The operator upon seeing the line lamp lighted, inserts her answering plug 7 into the line jack 3, and at the same time connects her set to the cord circuit by actuating the listening key 20. A circuit is now completed through the cutoff relay (5 over the following path: battery 25, supervisory lamp 9, conductor 26, contact 27, conductor 28, sleeve side of the plug and jack 7 and 3, respectively,-coil of relay ('3, to ground. Simultaneously with the energization of .relay 6, relay 10 is operated by the closure of the following circuit: battery 29, right-hand winding of relay 10, conductor 30, line wire 1, through the substation. and back over line wire 2, conductors 31, 32, left-hand winding of relay 10, to ground. Relay 10 in pulling up its armature opens its back contact 27, thereby extinguishing the supervisory lamp 9, as not sufficient current will flow through the resistance 23 to light the lamp.

The operator upon ascertaining that the calling subscriber desires connection with substation B, tests the busy condition of that line by touching the tip of her calling plug 8 to the sleeve of the line jack 3 associated with said line, as is common practice in the operation of multiple switchboards. If the called line is in use, the sleeve of the multiple jacks associated-therewith will have battery connected thereto at the time the busy test is made, and the operator in touching the tip of her plug 8 to the sleeve of the jack of said line (assuming substation B is busy), establishes the following circuit: battery from the sleeve of the jack, tip strand of plug 8, contact 34, conductor 35, contact 86, conductor 37, winding of relay 14, conductor 38, through the tertiary winding of the induction coil 39 associated with the operators set to ground. By this operation, the customary busy tone will be induced into the operators receiver which informs her of the busy condition of the tested line. It may be noted here that the relay 14 may, or may not, have been sufficiently energized to have been actuated upon the completion of the circuit just described, but it is preferred to have this relay of a type quick in responding. The operator, by holding the tip of her plug on the sleeve of the line jack of substation B for a period somewhat longer than is customary for her to do when originally testing the condition of the called line, permits the closure of the circuit through the relay 14 sufficiently long to operate said relay and effect the operation of the slowly responding relay 12. Relay let in operating, closes contact 46, thus establishing a circuit for the relay 12 which may be traced as follows: battery 59, front contact 33 of relay 10, conductor 10, contact 4-1, conductor 42, coil. of relay -12, conductor 43, contact 44:, conductor 45, contact 46, to ground. Upon the energization of relay 12, it forms a looking circuit for itself over the following path: battery 59, front contact 33, conductor l0, contact &1, conductor 42, winding of relay 12, contact 47, conductors e8, 28, sleeve side of the plug and jack 7 and 3, respectively, coil of relay 6, to ground. The busy signal is now connected to the subscribers line over a path which may be traced as follows: battery 29, right-hand winding of relay 10, conductor 30, over the line circuit and back, conductor 31, contact 50, to ground. It will be apparent that by virtue of the relay 12 establishing a locking circuit for itself upon energization. the operator is free to withdraw the callingplug 8 from the jack of the tested line and at the same time disconnect her set from the cord circuit, as the busy signal will be continued back upon the line of the calling subscriber until the circuit through the relay 12 has been ruptured. This may be accomplished by the subscriber workinghis switch book, which will effect the (leenergization of relay 10 and the consequent deenergization of relay 12 by the opening of the contact At the same time, the operator will be given the disconnect signal by the'lighting of the supervisory lamp over the following path: battery 25, lamp 9, conductor 26, contact 27, conductor 28, sleeve side of the plug 7 and jack 3, coil of relay 6, to ground. If the subscriber wishes to initiate another call, or communicate with the operator, he may attract her attention by working his switch hook, which in making and breaking the circuit through the supervisory lamp 9 will cause the same to flash, thereby gaining the notice of the operator.

It may be noted here, that in event the called line happened to be a trunk line running to a private branch exchange, and was busy when tested by the operator, due to the fact that the relay 12 is of a type slow in responding, she would have had an opportunity of testing all of the trunk lines running to the given private branch exchange before the busy signal would have been connected to the calling subscribers line. In event all of the trunks happened to be busy, the operator would then hold the tip of her calling plug on the jack of the last trunk tested long enough to permit the actuation of the relay 12 and thus connect the busy signal to the subscribers line by means of the conjoint action of the relays 12 and 14.

,Assuming' that the substation B was not in use when wanted by subscriber A, the operator, after testing the line and finding it free, would insert the calling plug 8 into line jack 3. Ringing current may'then be applied to the line B by the operator depressing any one of the four keys 16 to a way-down position, which act would complete the circuit for the ringing relay 18 which may be traced as follows: battery 55, contact 57, conductor 58, coil of relay 18, contact 17, to ground. Upon actuation, relay 18 forms a locking circuit for itself through the closure of the following circuit: battery 55, contact 57, conductor 58,

winding of relay 18, contact 60, conductor 61, contact 62, to ground. Thus ringing current is now applied to the line of substation B over the following path: generator source 16, conductor 63, coil of relay 64, conductor 65, front contact 67, out over the line and return, contact 66, to ground. Upon the called party removing his receiver from the switch hook, the relay 64 becomes energized, opening contact 62, thereby interrupting the locking circuit of the relay 18, which in turn removes ringing current from the line of substation B.

Simultaneously with the removal of the ringing current from the line, the relay 11 is energized over the following path: battery 70, right-hand winding of relay 11, conductor 56, ring strand of the plug 8, out over the line and returning by the tip strand, contact 34, conductor 35, contact 36, conductor 37, coil of relay 14, conductor 38, to ground. It will be noted that to effect the closure of the circuit just traced, the operator must not restore her listening key until the called party has responded. In pulling up its armature, relay 11 through the closure of contact 57, maintains itself energized in a manner self-evident. When subscriber B replaces his receiver upon the switch hook, the operator is informed of this act by the lighting of the supervisory lamp 9 over the following circuit: battery 51, lamp 9, conductor 52, contact 53, conductor 54, sleeve side of the plug 8 and jack 3, winding of relay 6, to ground.

In case the operator. should inadvertently plug in on a line already in use, the relay 21, upon energization would open-circuit the relay 12 which controls the application of the busy tone to the subscribers line, by opening the contact 41. This feature prevents either the called or the calling sub scriber from receiving the busy signal, which is an advantage if the operator had attempted to call a given subscriber who was in the act of initiating a call or hanging up his receiver at the completion of a call. It will be apparent that the application of the busy tone to the subscribers line is under the control of both of the relays 12 or 21.

The fact that the calling subscriber maintains control of his line at all times through the means herein described, makes it feasible to employ the use of a graphophone as a busy signal if desired. In event the graphophone was used in giving a busy signal and had been connected to a subscribers line, if it proved displeasing to the subscriber, he may rid himself of the annoyance by merely working his switch hook.

From the above it will be apparent that an operator can make a quick busy test.

aving once completed the necessary steps to connect the busy signal to a calling subscribers line, in event the called line is in use, she may restore the calling plug to nor mal position and disconnect her set from the link circuit. The operator is thereby relieved of the necessity of informing the calling subscriber that the line called is in use, or of connecting her calling plug to a special busy jack. Her time is thus saved, thereby increasing her efiiciency. If the calling party wishes further service, or hangs up his receiver, the operator is immediately notified of that fact.

at is claimed is: v

1. A telephone system including telephone lines terminating in jacks at a central office, a link circuit at the central oflice for uniting lines in conversation, a busy signal, means made operative when said link circuit is contacted with a busy line to connect saidsignal to a calling line, means under the control of the calling subscriber for disconnecting said signal from his line, and means for re establishing telephonic connection with an operator without the necessity of disconnecting said link circuit from the jack of the calling line.

2. A telephone system including telephone lines terminating at a central oflice, a link circuit at the central oflice for uniting lines in conversation, supervisory apparatus included in said link circuit, a busy signal, means made operative when said link circuit is contacted with a busy line to connect said signal to the line of a calling subscriber, and means controlled by the calling subscriber for disconnecting said signal from the calling line and for maintaining said supervisory apparatus under control of the calling subscriber.

3. A telephone system comprising a calling and a called telephone line terminating at a central office, a link circuit for connecting the lines together, a supervisory signaling device in the link circuit, a tone-producing device at the central office, means for connecting the tone-producing device in circuit relation with the calling line, means controlled by the calling subscriber for disconnecting the tone-producing device from circuit relation with the calling line and for causing the operation of the supervisory signaling device, and means under control of the calling subscriber for thereafter start ing the operation of the supervisory signaling device.

4. A telephone system comprising telephone lin'es terminating at a central office, a link circuit connected with one of the lines as a calling line, supervisory apparatus therefor, a quick and a slow-acting electromagnetic device, energizing circuits therefor completed upon engagement of the link circuit with the terminal of a busy line, a busy signal connected with the calling line upon the energization of the devices, and means controlled over the calling line for disconnecting the busy signal therefrom and for maintaining the supervisory apparatus under control of the calling subscriber.

5. In a telephone system, a calling and a called line terminating at a central oliice, a link circuit for connecting the lines together, a tone-producing device at the central oiiice, and switching mechanism controlled by and operated while the busy test is being made on the called line for con necting the tone-producing device in circuit relation with the calling line at the expiration of a predetermined period.

6. In a telephone system comprising a calling and a called telephone line terminating at a central office, a link circuit for connecting the lines together, a tone producing device, means for connecting said device in circuit relation with the calling line when said link circuit is contacted with the terminal of a busy called line, means under the control of the calling subscriber for disconnecting said device from circuit relation therewith, and means for subsequently reestablishing telephonic connection with an operator through said link circuit without the necessity of disconnecting said link circuit from the calling line.

7. A telephone system comprising a calling and a called telephone line terminating at a central office, a link circuit for connectin g the lines together, supervisory apparatus in the link circuit, a tone-producing device, means for connecting the toneproducing device in circuit relation with the calling line when said link circuit is contacted with the terminal of a busy called line, and means controlled by the calling subscriber for removing the tone-producing device from circuit relation therewith and thereafter maintaining the supervisory apparatus under control of the calling subscriber.

8. In a telephone system, the combination of calling and called telephone lines, a main station at which said lines terminate, a telephone line connector at the main station pro-- vided with switching mechanism to connect said connector to a called line, busy signal mechanism associated with said connector, means normally under the joint control of said switching mechanism and the calling subscriber to connect said signal mechanism in circuit with the calling line when said switching mechanism is contacted with the terminal of a line to which another connector is connected, apparatus automatically removing said means from. the control of said switching mechanism when said busy signal mechanism is connected to said calling line, and devices controlled by the calling subscriber for disconnecting said signal mechanism from the calling line and restoring the control of said means to the joint control of said switching mechanism and said calling subscriber.

9. In a telephone system, the combination of a main station, a plurality of substations one of which is a calling substation, a plurality of telephone lines leading from the substations to the main station including a calling telephone line to which the calling substation is connected, a telephone line connector at the main station for connecting telephone lines together adapted to be connected to said calling line, switching means for connecting said connector to a called line, controlled by said switching means for connecting said busy signal mechanism in circuit with the calling subscriber, said apparatus being made operative when said connector is contacted with a line to which another connector is connected, means for removing said apparatus :trom the control of said switching means and placing such apparatus under the sole control of the calling subscriber, and means controlled by the calling subscriber for causing the disconnection of said mechanism from the calling line and restoring it to the control of the switching means.

10. In a telephone system, the combination of a telephone line, a telephone line connector, busy signal mechanism associated therewith, means normally controlled by the connector and operative when the connector is contacted with a line to which another connector is connected for connecting said mechanism to the calling line, apparatus for placing said means under the sole control of the calling subscriber, and means controlled by the calling subscriber r'or causing the disconnection of said mechanism from the calling line and reassigning control thereof to the connector.

11. In a telephone system, the combination of a main line, a plurality of telephone busy signal mechanism and apparatus Cil lines leading to the main station, one of which is a calling line upon which there is a calling subscribers substation, a connector at the main station for connecting telephone lines together adapted to be connected to the calling line, switching mechanism for connecting the connector to a called line, busy signal mechanism associated with the connector, apparatus including a relay for connecting the busy signal mechanism to the calling line, said apparatus being made operative when the switching mechanism is contacted with a line to which another con nector is connected, a locking circuit for said relay independent of the said switching mechanism, and means controlled by the calling line governing said locking circuit and adapted when the calling line is opened to interrupt said locking circuit.

12. In a telephone system, the combination of a main station, a plurality of telephone lines leading from substations to said main station including a calling and a called line, connectors at the main station for con necting telephone lines together, busy signaling mechanism in said telephone system, apparatus for connecting said mechanism in circuit with a calling subscriber when a connector connected to the calling line is contacted with the terminal of a line connected to another connector, means thereupon cooperating with the apparatus for removing the control thereof from the calling end of the connector and means controlled by the calling subscriber for disconnecting said mechanism from the calling line until said line is again contacted with a busy called line.

13. In a telephone system, the combination of a main station, a plurality of telephone lines leading from substations to the main station, a telephone line connector at the main station adapted to be connected to the calling line, means including a plug provided with a tip contact for connecting the connector with the called line, busy sig nal mechanism in said system, an apparatus made operative when the tip of said plug 14. In a telephone system, the combination of a main station, a calling telephone line leading to the main station, substation apparatus on said line including an automatic receiver hook switch, a called line leading to the main station, a cord circuit at the main station, an answering switch which when closed connects the cord to the calling line, a second and calling switchfor connecting the cord to the called line, said switch including switching terminals of the cord and switching terminals of the line, busy signal mechanism associated with the cord, apparatus for causing said mechanism to extend a prolonged busy signal to the calling subscriber, means under thejoint control of the calling subscriber and the operator during the establishment of a connection and actuated when the call ing switch terminals of a cord and a called line to which another cord is connected are contacted to cause said mechanism to extend the busy signal to the calling subscriber, devices controlled by said means to place said apparatus under the sole control of the subscriber, and mechanism operating automatically when the calling subscribers hook switch is opened to restore said apparatus to the joint control of the calling subscriber and operator.

In witness whereof, I hereunto subscribe my name this 10th day of December A. D.,

- HENRY P. GLAUSEN.

Witnesses:

E. EDLER, K. L. STAHL.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G.

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