US1203851A - System for controlling electrical circuits. - Google Patents

Description

E. HLCLARK.

SYSTEM FOR CONTROLLING ELECTRICAL cmcuns.

APPLICATION FILED JULY 2.1915.

1 303,85 1. Pzttented Nov. 7', 1916.

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SYSTEM FOR CONTROLLING ELECTRICAL CIRCUITS. APPLICATION FILED JUL Y 2. 19151 Patented Nov. 7, 1916.

5 SHEETS-SHEET 2 E. H. CLARK. SYSTEM FOR commune ELECTRICAL cmcuns.

APPLICATION FILED JULY 2,19I5- 1,203, 85 1, Patented Nov. 7, 1916.

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E. H. CLARK.

SYSTEM FOR CONTROLLING ELECTRICAL CIRCUITS.

APPLLCATION FILED JULY 2,1915.

Patented Nov. 7, 1916 5 $HEETSSHEET 4 N gm j l E F 32 Wflhessesn //7venf0/ Edgar H C/ar/n E. H. puma. SYSTEM FOR CONTRQLLINGEL ECTRICAL CHLJHTS.

- APPLICATlON FIL-ED JU LY 2, I9I5.

1,203,85 1. Patented Nov. 7, 1916.

. 5 SHEETSSHEET 5 kn N 7 a A flL w W E 1 pm UNITED sTA Es PATENT OFFICE.

EDGAR HARRISON CLARK, OF NEW YORK, N. Y., ASSIGNOR, BY MESNE ASSIGNMENTS, TO WESTERN ELECTRIC COMPANY, INCORPORATED, A CORPORATION OF NEW YORK.

SYSTEM FOR CONTROLLING ELECTRICAL CIRCIIITS.

Patented Nov. '1, 1916.

Application filed July 2, 1915. Serial No. 37,696.

To all whom it may concern Be it -known.that I, EDGAR HARRISON CLARK, a citizen of the United States, residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Systems for Controlling Electrical Circuits,-

of which the following is a full, clear, concise, and exact description.

This invention relates toanimproved system for controlling electrical circuits, and is particularly directed toward the provision of an organization for securing the selective operation of any one of a number of mechanisms employed preferably .for directing or controlling the operation of a telephone'ex change system.

This invention has particularly to do with an organization for enabling a succession of electrical impulses to effectthe selective operation of any one of a series of electrical responsive devices through the medium of a train of electrically actuated mechanisms which are brought into operative relation with the source of impulses 'one after the other by the successive impulses of current. In the organization of this invention each mechanism of the train in operating renders operable the next mechanism in the train and restores to normal condition the previously operated mechanism, the particular mechanism and associated responsive device left operated at the termination of the train of impulses being that which corresponds in number with the number of'impulses in the train. An organization is provided in which this selective control of a series of responsive devices by a train of impulses is combined with a telephone exchange system of the call distributing type in such a way as to form an improved system for automatically identifying a calling line with respect to its class of service, or other special characteristics, such as the particular exchange or oflice to which the line belongs. In a call distributing system the subscribers lines, instead of terminating directly upon the answering operators position, are extended to that position, as they call, by means of a trunk. The operator is thus deprived of such identification of the calling line as would be furnished by the line terminal itself, if that appeared before her.

The selective control organization is applied to a call distributing system in such a various lines.

way as automatically to apprise the operator of the identity of the calling line, characteristic trains of impulses being applied to the various lines, and the operators position being equipped with'a train of relays and associated signals which respond selectively to the number of impulses in the identifying trains.

The invention will be more particularly described by reference to the accompanying drawings which show a preferred embodiment of it, and in which Figure 1 illustrates three telephone lines with their central oflice terminal equipment and connections; Fig. 2 illustrates a line finder and cord finder circuit for extending the circuit of a calling line; Figs. 3 and 4 illustrate a cord circuit terminating in a plug, ,a called line into a spring jack of which the plug may be inserted, and a part of the operators circuit and Fig. 5 illustrates the part of the operators circuit that has to do with determining the identity of a calling line with respect to its class of service.

In the particular embodiment of this'invention illustrated in the accompanying necessary to illustrate it specifically. Cut- I off relays 21, 23, 25 and line relays 22, 24 and 26 are associated with the three lines in the usual Way.

Each of the lines has four conductors, two being the ordinar 1 line conductors, and the other two, 64 and 60, being conductors local to the exchange. The local conductor 64 of each line has included in it a winding of the associated cutofi' relay, while the conductor 60 in each case extends to the common iden tifying device or apparatus for producing the impulses which serve to identify the This device is represented diagrammatically at 13 in.the drawing, and is illustrated as comprising four commutators, 1, 2, 3, 4,,the first three of which operof current, respectively, in their associated of the i entifying or commutator device 13.

conductors in, each cycle of rotation oi the device, while the fourth produces a single impulse of current in each cycle of rotation .that serves as a pick-up impulse to mark the duration of the cycle. It is to be understood that the four commutator disks or sections illustrated are carried upon a common driving shaft, or otherwise so associated that they rotate together and maintain substantially the same relation to each other as that diagrammatically shown. This is such that between two successive pick-up impulses produced by commutator section 4, one 1m- .pulse is produced by commutator section 1,

'two impulses are produced by commutator rfiection 2, and three impulses are produced 51 commutator section 3. In the present tor lines by two impulses of current, and of the message rate lines by three impulsesof current roduced in each cycleof rotation Consequently in the organization shown in the drawings the identifying conductor of the line to station A is extended to section 3 of the commutator, that of the line to station B is extended to section '2 of the commutator, while that of the line to station C A isextended'to section 1 of the commutator.

A When any line calls, it is extended, as shown in the present embodiment, by means of a line finder switch 11 and a cord finder switch 12, to a connecting cord circuit which terminates upon a connecting plug 14 that is adapted to be inserted by the operator into any spring jack 15 in order to complete the connection between the calling and the called telephone lines. When the cord finder switch 12 finds the connecting cord circuit that is to be used in completing the connection, the calling line is automatically extended by way of the connecting cord circuit to the telephone set and controlling switches of the operator at whose position the selected connecting cord 'circuit is 10- cated.

Among the conductors of the connecting cord circuit that are extended to the associated operators circuits when the'connecting cord is selected, there are four-60, 61, 6'2 and 63-which are particularly concerned with the operation of the apparatus that has to do with the identification of the line with respect to its class of service.

These conductors lead to the class-of-service indicating device with which the operator is provided, conductor 60 being the fourth or identifyin wire of the line that is calling, and con uctors 61, 62 and 63 being the wires over which the class-of-service responsive apparatus is brought into or out of ac-. tion as the operators circuits are connected with or disconnected from the. connecting cord circuit. i

The identifying responsive device to which the conductors 60, 61, 62 and 63 .lead, comprises, in the present instance, three lamps with a group of relays for controllin them. Before describing the circuits in detafi, there will be outlined briefly the manner in which the operators identifying or signal controlling device cooperates with the impulse producing device to apprise the operator of the identity of the extended line with respect to its class of service. a

The extension of a calling line to a connecting cord, and thus to the associated op- .erator, operates sequence switch 165 to close conductors 60, 61 and 63 extending to the operators identity indicating apparatus, thus making this apparatus responsive to subsequently received identifying impulses. The sequence switch 165, as well as the sequence switches 36, 71 and 118 shown at various points in the organization for controlling the circuit connections, may be of the type disclosed in'Patent 1,127,108, issued February 9, 1915 to Reynolds and Baldwin. Each consists of 'an electromagnetically controlled motor or driving mechanism and a number of associated switch cams. The switch cams associated with the sequence switch 165 are those shown on Fig. 3 of the drawing; those associated. with sequence switch 36 are the ones shown on Fig. 2 of the drawing; those associated with the se-.

uence switch 71 are shown on Fi 5 of the rawing; and those associated wit 1 sequence switch 118 are shown in Fig. 4 of the drawing and are also indicated by numbered circles in Fig. 3 of the drawing. To each of the contacts associated with the various sequence switch cams are applied certain numerals. These numerals in the case of the cams 166, 37, 75 and 157 indicate the only positions of the associated sequence'switch in which these particular contacts are open; numerals applied to all of the other contacts of each sequence switch indicatethe only positions of the particular associated switch in which the associated contacts are closed.

In outline, the operation is as follows: The'closure of conductor 63 connects the pick-up commutator 4 with sequence switch 71, and the first pick-up impulse produced thereafter causes the sequence switch to move its contacts into their second position.

It will be understood that the pick-up commutator 4 shown in Fig. 3,to which particular reference is now being made, is the part that is illustrated in Fig. l in association with the impulse producing parts 1, 2 and 3.

When sequence switch 71 is in its second position, the identifying conductor 60 of the calling line is extended to the group of signal controlling relays. The first impulse over the identifying conductor operates relay 81 of the first pair, which relay in operating-operates the associated relay 80 and lights the associated lamp. 82. A second impulse of current over the identifying conductor flows to the second pair of relays, 83 and 84, by way of a path prepared by the operation of the first pair of relays, operating them and their associated lamp 85, and at the same time deenergizingthe first pair of .relays 80 and 81, and extinguishing the first lamp 82. A third impulse of current over 'the identifying conductor 60 flows to the third pair of relays 86 and 87 by way of a path prepared by the operation of the second pair of relays, operating thethird pair and their associated lamp 88, and at the same time deenergizing the second pair of relays and extinguishing the second lamp 85.

The end of the cycle of rotation of the commutator is marked by the production of a pick-up impulse, which flows through,

the sequence switch magnet 71 by way of conductor 63 and moves the sequence switch contacts into their third position. In moving out of its second position the sequence switch disconnects the identifying conductor 60 from the identifying signal controlling relays, thus preventing any further identifying impulses from flowing to them. If one impulse has been received during the cycle i the lamp 82 remains lighted, indicating to the operator that the calling line is a flat rate line; if two impulses have been received I during the cycle the lamp 85 remains lighted, indicating to the operator that the calling line is a coin-collector line; if three impulses have been received during the cycle the lamp 88 remains lighted, indicating to the operator that the calling .line is a message-rate .line. Of course it will be understood that this codeof signals is purely arbitrary, and that information with regard to any peculiarity or characteristic of a calling line may be conveyed to the operator by any signal indication chosen for that purpose.

As long as sequence switch 165 remains in its listening position, the associated responsive mechanism is maintained operated, and the lamp that has been selected is kept lighted, the maintaining circuits being controlled by relay 70. hen the relay is switch 71 by way of conduct0r62 that causes.

it to move out of its third and around to its first or normal position.

Inasmuch as this invention is not particularly concerned with the character of the circuits over which the calling line is extended to the operators position, and over which the calling line is extended to the called line after the operator has obtained such identification of the calling line and such information concerning the called line as may be necessary for her purpose, these intermediate circuits and apparatus will be described only to the extent that they are involved in the operation which has particularly to do with the disclosure of this invention. The organization which has been chosen for the purpose of showing a specific embodiment of this inventiomis one which utilizes automatic finder switches for finding a calling line and for extending the calling line to a connecting cord circuit that is at the time idle and available, and which utilizes a plug terminal for the connecting cord circuit, which plug terminal is inserted by the operator into the spring-jack of the wanted line. The finder switches, of which certain of the brushes and stationary contact terminals are indicated at 11 and 12 in Fig. 2 of the drawing, may be of the type illustrated and departicularly described, in permitting current to flow, by way of conductor 112, through one winding of the relay 52 associated with the line and cord finder circuit. This relay closes its contacts 53 and completes a circuit by way of contacts 48, 46 and 45 of sequence switch 36 to energize the up-drive magnet (see McQuarrie, patent above referred to) and cause the line finder switch 11 to connect with the terminals of the calling line. The sequence switch 36 is adapted to rest in positions 1, 2, 3, 4, 6, 7, 8, 9, 14, 15, 16 and 17. Of these positions, theg following are of interest in connection with this description:

Position 1-Normal.

Position 2Awaiting starting circuit.

Position 4-Hunting calling line.

Position 9-Hunting cord circuit.

Position 1l-Talking. It is not considered necessary to show th connection of the circuit last traced with the motor magnet of the line finder switch, nor the path over which the finding of the calling lineresults in the sequence switch 36 being advanced through the intermediate stages until it reaches position 9, which is the position in which the connecting cord circuit is hunted. The circuits for accomplishing this are well known in the art.

When the brush 30 oi the line finder 11 comes into engagement with the correspond ng terminal of the calling line, a circuit is completed that includes battery, resistance i3, sequence switch contacts 42, brush 30 and its cooperating line contacts, and the cutoff re lay 21 23 or 25 of the calling line. T1115 e nergizes the cutoff relay and causes it to disconnect the associated line relay branch from the line. \Vhen the sequence switch moves into position' 9, the up-drive magnet of the cord finding switch 12 is made active, over circuits which need not be described, to cause the brushes 32, 33, 31 and 35 of the cord finder switch to engage corresponding contact terminals of an idle connecting cord. When the idle connecting cord is found, the sequence switch 36 is moved, by the closure of circuits that it is unnecessary to describe, into position 11, which is the talking position. In this position of the sequence switch, the two talking conductors 65 and 66 of the finder circuit are connected through from brushes 28 and 29 of the line finder switch to brushes 32 and 33 of the cord finder switch, by way of contacts 39 and 40 of the sequence switch, which contacts are closed in position 14. The third conductor 61 of the circuit is closed, in this position, from brush 30 of the line finder switch to brush 34 of the cord finder switch by way of contacts 41 of the sequence switch, one of the windings of relay 52, and contacts 50 and 51 of the sequence switch. The fourth or identifying conductor 60 is closed from brush 31 of the line finder switch to brush 35 of the cord finder switch by way of contacts 44; of the sequence switch, contacts 53 of relay 52, and contacts 46 and 47 of the sequence switch.

It will be noted that the motor magnet of the sequence switch, while the switch is-resting in the talking position 14, is under the control of contacts 54 of the relay 52 by way of contacts 38 of the sequence switch closed in position 11; so that in the talking position, relay 52 acts as a holding relay, the deenergization of which causes the sequence switch to move to its next position.

\Vl1ile the extension of the calling line to the conductors 60, 61, and 66 of an operators cord circuit has been described as being.

effected through the medium of a finder circuit controlled by the sequence switch 36 and terminating in the brushes of automatic finder switches 11 and 12, it is obvious that the connection terminals 11 and 12 may be plug and spring jack terminals manipulated by an operator, that the contacts described as sequence switch contacts may be manually operated switches, and that the holding relay 52 may control, if desired, adisconnect signal, all in accordance with the common and wellknown practice of the art.

The circuits of the connecting cord are governed by a sequence switch 165 which has three resting positions, as determined by the master contact 166, these resting pos tions being as follows:

Position 1-Normal.

Position 7Listening-in.

Position 15Listening-out.

When the cord circuit is connected with by the cord finder switch 12, the sequence switch 165 is in its normal or No. 1 position. The engaging of brush 35 of the cord finder switch with the corres onding contact of the idle cord circuit, a vances the sequence switch 36 of the finder circuit from its No. 9 or hunting position to its No. 14 or talkin position by well-known circuits which nee not be particularly illustrated or described; and as soon as sequence switch 36 leaves its No. 9 position, it completes a circuit which may be traced from ground through-resistance coil 114, sequence switch contacts and 51, brush 3-! and its corresponding cord circuit contact, conductor 64, contact 67 of relay 68, sequence switch contacts 69 and winding of relay 113 to battery.

Relay 113 in operating closes a circuit for the energization of the motor ma at of sequence switch 165, by way 0 sequence switch contacts 115, contacts ofcalling plug sequence switch 118 closed in position ho. 1 of that switch and contacts 117 of relay 113, which movesthe sequence switch to its No. 7 or listening-in position.

In order to avoid unnecessary confusion in the circuits, the expedient has been adopted of showing, by means of circles with appropriate numbers inclosed therein, the positions of the calling plug sequence switch 118 in which this switch acts to close the path upon which the numbered circles are placed. ()therwise, in order to indicate the control of the conductors by sequence switch 118, it would be necessary to extend them in each case to the vicinity of that switch, which is at a point somewhat remote in the drawing.

As soon as sequence switch 165 moves out of position 1, it closes an energizing circuit for relay 68 as follows: battery, winding of relay 68, contacts 119 of sequence switch 165 to ground. The operation of relay 68 closes a locking circuit for the relay as follows: battery, winding of relay 68, contacts 120 of that relay, and contacts 119 closed in position 1 to 7 of sequence switch 165 to ground. Subsequently there is an alternative ath closed in positions to 17} of the calling plug sequence 118 to ground. This locking circuit provides for the continued energizetion of relay 68 from the time the connecting plug 14 is inserted in the spring jack of the called line until it-is removed.

Relay 68 in operating disconnects the third strand 64 from the relay 113 and con nects it with the relay 121. This closes the path of the third strand'64 of the connecting circuit that remains normally completed during the period of extension of the calling line to the operators circuit and to the called line. This path is as follows: battery, winding of relay 121, back contacts 122 of relay 123, front contacts 67 of relay 68, contact terminal and brush 34 of the cord finder switch 12, contacts 51 and 50 of sequence switch 36, winding of holding relay 52, sequence switch contacts 41, brush 30 of line finder switch 11 and the associated line contact, Winding of cutoff relay 21, 23 or to ground. The relay 121, the holding relay 52, and the cutoff relay are thus kept energized while the line is extended.

l/Vhen sequence switch 165 moves into position 7, it breaks the direct talking path through conductors 65 and 66 of the connecting cord circuit, and substitutes a loop which passes through contacts of certain of the operators control keys 124 and 125 and has connectionwith the operators telephone 1 set 16. aThis loop is controlled. in the contacts 126, 127, 128 and 129 of sequence switch 165. The operators key 124, thus brought into circuit in position 7 of sequence switch 165, is for the purpose of connecting high-voltage current of negative polarity with the calling line to bring about the return of a coin which may be held in the coin box of the line; while operators key 125 is for'the purpose of ringing back on the calling line circuit. 4

The movement of sequence switch 165 into position 7 brings the operators telephone into circuit, as above described, and also brings'the operators class-of-service indicatin mechanism into association with the circult. The latter is accomplished by the closure in position 7 of the sequence switch contacts 130, 131 and 78. The closure of contact 130 completes a path for the flow of current through conductor 61 including relay 70 of the class-of-service indicating apparatus, the closure of sequence switch contacts 131 extends the fourth or identifying conductor of the line circuit to the class-of-service indicating apparatus, and the closure of sequence switch contact 78 brings the pick-up impulse commutator into association with the class-of-service sequence switch 71'. This automatically causes the indicating apparatus to operate to apprise the operator of the characteristics of the calling line with which the apparatus has just acted to connect her. The manner in which the apparatus acts to effect this result is as follows: The closure of conductor 63 connects-the motor magnet of'sequence switch 71 with the pick-up commutator over the following path: battery, magnet of sequence switch 71, sequence switch contacts 72, contacts 78 of sequence switch 165, and to earth by way of commutator section 4-at the beginning of the next folthe master contact 75 of the sequence switch.

In the second position of the sequence switch the identifying conductor 60 is extended by way of sequence switch contacts 74 to the group of signal controlling relays.

The first identifying impulse that flows over conductor 60 after contacts 74 are closed actuates relay 81 over-the followingcircuit: battery, winding of relay 81, normally closed contacts 133 of relay 81, back contacts 134 of relay 86, back contacts 135 of relay 83, and thence following identifying conductor 60 through the various switch mechanisms heretofore described to ground by way of the particular identifying commutator 1, 2 or 3 associated with the particular line that is calling. Current flowing in this path operates relay 81 and causes it to close a locking circuit for itself at its front contacts, this locking circuit extending by way of the winding of the associated relay 80, back contacts 136 of relay 83, and

front contacts 76 of relay to ground.

from identifying conductor 60. and relay 80 in operating connects the identifying conductor with relay 84 of the second pair. As

va result the second impulse of identifying current flows from battery through the winding of relay 84, normally closed contacts 137 of that relay, front contacts 138 of relay 80. and to the identifying conductor 60. This energizes relay 84, which in operating disconnects itself from the identifying conductor, and closes a locking circuit for itself, which locking circuit extends through the winding of the associated relay83, back contacts 140 of relay 86, and front contact 76 of relay 70 to ground. lurrent in this circuit energizes relay 83, which in operating opens atits contacts 136 the locking circuit which had been holding relays 80 and 81 energized and their associated lamp 82 lighted and closes at its contacts 135 a conducting path between the conductor 60 and the winding of relay 87 of the third pair so that a third impulse of identifying cur-.

lamp 85 is included in the circuit in parallel with the winding of the relay 84 of the second pair, and is kept lighted as long as the second pair of relays 83 and 84 are held energized.

If there is a third impulse of current produced in the identifying conductor, it flows through relay 87 of the third pair by way of the path prepared for it by the closure of contacts 135 of the previously operated relay 83, the circuit being from battery through the winding of relay 87, normally closed contacts 139 of that relay, front contacts 135 of relay 83, and thence by way of conductor 60 and the impulse producing commutator to ground. Relay 87 in operating closes a locking circuit for itself that includes the winding of the associated relay 86 and extends to ground by way ,of contacts 76 of relay 70. Relay 86 in operating opens the circuit that has been keeping the second pair of relays 83 and Si energized and their associated lamp 85 lighted. The third lamp 88 is included in the circuit over which the third pair of relays 86 and 87 are energized, and is lighted when these relays are operated.

At the completion of the cycle of rotation of the commutator, section 4 again operates to close the circuit of the conductor associated with it. The pick-up impulse thus produced flows from battery through the clutch magnet of sequence switch 71, sequence switch contacts 72, contacts 78 of sequence switch 165 and pick-up commutator 4 to ground. This causes sequence switch." pares the path for 71 to move into its third position. In leaving its second position the sequence switch opens its contacts 74. thus preventing any further impulses of identifying current from reaching the group of signal controlling or counting relays. At the conclusion of the cycle the first lamp the second lamp 85 or the third lamp 853 will remain lighted, depending upon whether one. two or three impulses of identifying current passed over the identifying conductor during the cycle, which in turn depends upon whether the identifying conductor of the calling line is connected with section 1, section 2 or section 3 of the identifying commutator 13.

From the foregoing description of the selectively operating signal controlling organization of this invention. it may be seen that the signal controlling relay mechanisms exercise such reciprocal control over one another that they are. brought one at a time into operative relation w' th the identifying conductor, each mechanism in operating preparing the path for the operation of the next mechanism. and rendering inoperative the previously operated mechanism. The first pair of relays is normally in operative relation with the conductor (30. subject to the control of contacts 134 and 13?) associated with the other two pairs of relays. The first pair of relays in operating prepares, in contacts 138,

other is such that only one of these paths for the identifying impulses is closed at a time. It is further to be noted that each of the relay mechanisms in operating renders inoperative the previously operated mechanism by opening its locking circuit, thus obliterating the previously produced signal indication and insuring that only one of the signals will be displayed at a t'iine. Thus the signal indication of the first relay mechanism is destroyed by the opening of contacts 136 of the second relay mechanism, and the signal indication of the second relay mechanism is destroyed by the opening of contacts 140 of the third relay mechanism. Whichcver mechanism is left in its energized condition at the end of the cycle is finally released by the opening of contacts 76 when the relay '70 is deenergized.

In order to prevent the possibility of a.

single identifying impulse efl'ecting the op- 4 eration of more than one pair of relays, the relays 80, 83 and 86 preferably are relatively slow acting relays, which result may be obtained by providing them with copper sleeves or in any other well known way, the

object being to prevent the closure of the contact--such as 138, and 135-which prethe operation of the next pair of relays in order until the impulse that caused the operation of the preceding pair has terminated. By pro rly proportioning the speed of o eration o the relays, the rate of rotation o the impulse producing commutator 13 and the length of the commutator contact segments, each impulse is made to cause the operation of its corres riding pair of relays and to terminate be ore the path has been prepared for the operation of the succeeding pair. The relation must merely be such that the identifying impulse lasts long enough to cause the relay 81 or 84 to close its contacts, and terminates before the associated slow acting relay 80 or 83 closed its contacts.

From the foregoing detailed description it may be seen how the operators identity indicating apparatus operates when the seque'nce switch 165 of the connecting cord circuit moves into its No. 7 or listening position. to apprise the operator, by means of the particular lamp lighted, of the class of service for which the calling line is adapted. Thus informed, the operator is enabled to write suchtickets or memoranda, or give such service as her instructions require for this sort of a line.

Having learned the number of the line that the calling line desires connection with, the operator completes the connection by plug end of the connecting cord circuit are controlled by a sequence switch 118, the principal resting positions of which, as determined by the master contact'157, are as follows:

Position 1-Normal.

Position 2-Awaiting listening key sequence switch.

Position 5Ringing on. tip conductor.

Position 8,Ringing on tip conductor.

Position 11Ringing on ring conductor.

Position 13Ringing on ring conducton Position 16Awaiting supervisory re1ay.-

Position 17Ta1king.

The sequence switch 118 remains in position No. 1 until plug 1:i:'lS inserted, when it moves into position No. 2, and there waits upon certain actions in the associated connecting cord circuit, which are not particularly concerned with this invention and. need not be described, and presently is moved into position 5. In this position,- ringing current may be applied to the tip conductor of the cord by way of sequence switch contacts 158, the ring strand of the cord being connected to ground by way of' contacts 159. In position 8 of the sequence switch,- ringing current of a different sort may be applied to the tip strand and the ring strand grounded by way of the same sequence switch contacts. In positions Nos. 11 and 13, ringing current of diflerentsorts' may be applied to the ring strand and the tip strand grounded by way ofsequence' switch contacts 160 and .161 closed in these positions. Sequence switch 118 then moves to position 16 where it awaits the response of the calledfsubscriber; and upon the subscriber takinghis telephone from its hook,

- the sequence switch moves to position 17,

which is the talking position.

In the talkingposition, the conversational circuit is completed between the calling and the called subscribers by way of the windings of the repeatingcoil 162 and contacts 163 and 161 of sequence switch 118. The

' tip strand of the talking circuit also passes through contacts 175 of relay 176, which 'relay, with relay 167 is included in a con-' ductor extending from battery to the' sleeve of connecting plug 14. and thence to ground through the cutoff relay .of the-called line. Answering supervisory relay 168 and calling supervisory relay 169 are included in the ring strands of theconnecting cord circuit in the usual manner, and control, the associated answering and calling supervisory lamps in the usual w-ayavhen the sequence switch is in its talking position. I A call lamp 170 is also provided, this lamp being caused to flash by a commutator 171 while sequence switch 118 is in its first and second positions, to designate to the operator the connecting cord to which the calling line has been extended, and being thereafter caused to glow steadily until the called subscriber has answered, and the sequence switch 118 has moved into its talking position 17.

When the sequence switch 118 moved to position 2, at the time the operator inserted the calling plug 14 into the spring jack 15,

it closed contacts which completed a circuit that moved the sequence switch 165 out of its listening-in position 7. in which it had been standing, and into its listening-0111: po-

sition 15. This circuit is as follows: bat

sequence switch 118 closed in the second position, back contact 117 of relay 113 to ground. In moving out of its listening-in position 7, sequence switch 165 opens, in sequence -switch contacts 131, 130 and 78, thecircuit of conductors 60, 61 and 63, and closes, in sequence switch contacts 77, the circuit, of conductor 62 extending to the class-of-service responsive apparatus. paths of conductors 60 and 63 are ,already open in contacts'i' l and 72 of the class-0t service sequence switch 71. The opening of conductor 61 allows relay to fall back, thus opening the locking circuit and permitting the deenergization of whichever pair of relays andassociatedlamp was made operative by the identifying impulses. The closing of conductor 62 closes a circuit by way of contacts 73 of sequence switch 71 The for current to flow through the clutch magnet of sequence switch 71 and cause the quence switch to move around to its No. 1 or normal position. The operators line identifying apparatus is thus restored and placed in readiness to give another identify ing indication.

When it is resting in its listening-in position 7, the sequence switch 165 may also be moved into its listening-out position over a circuit which passes from battery through the motor magnet of sequence switch 165,

contacts 173 of the sequence switch and contacts of' the master listening-out key 174. If the sequence switch 118 associated with the calling plug is in, its first position when the master listening-out key 174 closes the circuit traced above, the sequence switch 165 finds a circuit to ground in its 15 position by way of contacts 177 of sequence switch 165, and contacts of the sequence switch 118 closed in the normal position of that switch. This condition causes the sequence switch 165 to pass through its 15-position-and return, to normal.

Assuming that the been inserted, and that the called subscriber has been signaled and has responded by taking his telephone from its book, the conversational circuit between the calling and calling plug ll has.

called subscribers stations is completed by way of the talking conductors 65 and 66,- sequence switch 36 standing in its osition 14, sequence switch 118 standing in its talking pos tion 17, and sequence switch 165 standing in its listening-out position 15, in which position the operators telephone set and the class-of-service responsive apparatus are disconnected from the circuit.

\Vhen the subscribers have finished their conversation they hang up their telephones,

listening-out her listening-in key 180. The pressing o as a result of which the answering supervisory relay 168 and the calling supervisory relay 169 of the connecting cord circuit are deenergized and cause the illumination of their associated supervisory lamps. Upon receiving this disconnect signal, the operator may, listen-in on the circuit by pressing this key closes the following circuit: ground, contacts 116 of sequence switch 165, motor magnet of sequence switch 165, battery. This energizes the sequence switch and causes it to move out of its listening-out position 15. But instead of stopping in position 1, the sequence switch finds a circuit in that 'position as follows: battery, motor magnet of sequence switch 165, contacts 181, contacts closed in positions 2 to 18 of the calling plug sequence switch 118, ground. This circuit causes the sequence switch 165 to move through position 1 and come to rest in its listening-in position 7. As a result, by pressing. her listening-in key 180, the operator reestablishes the connection oi her telephone set and of the class-of-service indicating apparatus with the connecting cord circuit, and the last mentioned apparatus thereupon operates, in the manner already described, to indicate again the class of service of the calling line.

If, for any reason, the operator wishes to do so, she may listen-in and listen-out on the connection as many while the connection is established between the two subscribers lines, by merely pressing her listening-in .key 180 and her master key 174, the sequence switch 165 being thus correspondingly moved to its listening-in position 7 or its listening-out position 15; and each time the sequence switch moves to the listening-in position, the lamps of the operators class-of-service responsive device again indicate the class-ofservice of the calling line.

At the conclusion of the conversation between the subscribers, and before taking down the connection, the operator presses her charge key 179. When this key is pressed, it causes the operation of two relays, 189 and 123, the circuit of the last mentioned relay being further controlled by contacts that are closed in osition 17 of the calling-plug sequence switc 118, so that the chargpjkey, has control over the relay 123 talking times as she cares tO only when the calling plu sequence switch is in its talking position, hat is, only when a connection has been completed with the called line. Assuming that this is the condition, and that the relay 123 is operated, it

the contacts of the switch 184. The branch normall closed includes the winding of a relative y high-resistance and sensitive relay 186 and a battery of, say, twenty-four volts; 3

while the other branch, which is closed when the switch 184 is operated, includes a relatively low-resistance and insensitive relay 187 and a battery of, say, forty-eight volts.

f -Each of the relays 186 and 187, when it operates, is adapted to operate a position register 188, and this position register, in operating, registers the connection and lights an associated pilot lamp.

The conductor 64, with whichone or the other ofthese branches is connected when the relay 123 is operated, is the third strand of the connecting cord circuit; and is an extension of the conductor of the calling line which includes the cut-ofi relay. If the calling line is a flat rate or coin collector line, its third conductor includes only the cutoff relay. If it is a message rate line, a message register 27 is also connected with the third conductor 6-1 in parallel with the cutoff relay. This message register 27 may be of a well-known ty e having two windings in series, one 0 which windings is short-circuited when the register operates to permit an increased flow of current over the circuit. When the line is a message rate line with the message register 27 connected, the branch that includes the winding of relay 187 and the forty-eight volt battery is included in the circuit. The relay 187 is message register acts'and short-circuits one of its windings, the increased flow of current is sufficient to.operate the relay 187. As a result, the relay 187 acts to operate the position register 188 and the" associated pilot lamp only after the message register 27 has operated.

If the calling line is not a message rate line, the relatively high resistance and more sensitive relay 186 is included inthe circuit of the third strand or conductor M, so that when the relay 123 operates, as a result of the depression of the charge key 179, the relay 186 acts to operate the position register 188 and light the "associated pilpt lamp without waiting for the operation ot some other device, such as the message register BEST AVAILABLE COP 27. Thus, one of the branches, that which includes the winding of the relay 187 and the forty-eight volt battery, is adapted to the circuit conditions present in message rate lines; while the other branch, that which includes the winding of relay 18(3 and the twenty-four volt battery, is adapted for the circuit conditions that are present in lines other than message rate. v

The other relay 189, which is operatec when the operator depresses her charge key 17 9, breaks, in its contacts 190, the tip conductor 66 of the connecting cord circuit, and connects the portion that extends to the calling line with a branch which ineludes normally open contacts of switch 191, the winding of apilot relay 193 and a protective lamp, and extends to the positive ole of a high potential source of current.

he current that flows by way of this path to the tip conductor of the calling line is for the purpose of operating the coin-box mechanism at the subscribers station to collect the deposited coin. The mechanism at the subscribers station involved in this operation, and in the operation of returning the coin when high potential current of the opposite polarity is applied to the calling line by way of the operators key 124, under control of the relay 19% operated in the listening position of the sequence switch 165, is well known in the art, and need not be particularly shown or described.

There are, therefore, three branches which may be closed when the operators charge key 179 is depressed, one of these being the branch of conductor 64 which'includes the relay 186 and low potential battery, another being the branch'ot the conductor (34 that includes .the relay 187 and the high potential battery, and the third being the extension of the tip conductor 66 of the line which includes the relay 193 and extends to the positive pole of the high potential source of current. Which of these three branches is to be closed when the. operator depresses her charge key 179, depends upon whether the calling line is a flat rate line, a message-rate line or a coin collector line, and of this the operator is informed by her class-of-service indicating device in the manner already described. It the calling line is a. flat rate line. the. switches 181- and 191 are left in their normal positions when the charge key 179 is depressed, and the result is that the position register 188 is operated. If the calling line is a message rate line, the. switch 184 is operated. either manually or otherwise, before the charge key 179 is depressed, and in consequence the connection register 27 of the calling line and the position register 188 are both operated. If the calling line is a coincollector line, the switch 191 is operated, either manually or otherwise, before the charge key 179 is depressed, and in consequence high potential current of positive polarity is applied to the tip'side of the calling line to collect the coin, and at the same time the relay 186 is actuated to operate the position register 188.

After the operator has pressed the charge key. she withdraws the plug 14 from the jack 15 of the called line. This starts a train of operations governed by the sequence switches, in a manner which need not be described, that results in all of the apparatus involved in the connection being restored to its normal condition.

With respect to those features of the or; ganization disclosed herein which have to do broadly with the provision in a'call distributing system of means for autonnitically apprising an operator of the identity of a calling hne, this invention is subordinate to that disclosed in the application of SB. lVilliams, Jr. filed May 22, 1915, Serial No. 29,875.

What is claimed is 1. A controlling apparatus comprising a source of electrical impulses, a train of relays, means for causing the first impulse to train, an energizing circuit for each succeeding relay of the train adapted to be brought into operative relation with said source of impulses by the operation of the preceding relay of the train, a locking circuit for each relay closed in the operation of said relay and opened in the operation of the succeeding relay of the train, and a switch for opening the locking circuit of the last relay of. the train.,

2. A controlling apparatus comprising a source of electrical impulses, atrain of relays, an energizing circuit for the first relay of the train normally adapted for connec tion with said source'of impulses, an energizing circuit for each succeeding relay of the train adapted to be brought into operative relation with said source of impulses by the operation of the preceding relay of the train, a, signal device operated in the operation of each relay, a locking circuit for each relay opened by the operation of the succeeding relay of the train, and aswitch for opening the locking circuit of which ever relay may remain operated at the termination of the train of impulses.

3. A Controlling system comprising a source of electrical impulses, a train of relays. means for causing successive impulses to effect the operation of successive relays of said train, a. signal associated with each relay and displayed in the operation of the same. and a locking circuit for each relav closed in the operation of said relay and opened in the operation of the succeeding relay of thetrain.

effect the operation of the first relay of the 4. Asignaling system comprising a source BE'ST AVAILABLECOF of electrical impulses, a train of electrically actuated signal devices, means for causing successive impulses to effect the operation of successive devices of said train, means associated with each device and rendered active in the operation thereof for maintaining said device in its operated condition, said maintaining means bein rendered inoperalive by the operation 0 the succeeding device in the train.

, 5. A controlling system comprising a source of impulses, a train of relays, an energizing circuit for the first relay in said train serially including normally closed contacts of the succeeding relays in the train,

' an energizing circuit for each succeeding relay operatively connected with said source of impulses by the operation of the preceding relay of the train. a locking: circuit for each relay made active in the operation thereof, means operated in the operation of each relay for rendering inactive the locking circuit of the preceding relay of the train, means for rendering inactive the locking circuit of the last relay of said train,v

and a responsive device associated with each relay and actuated in the operation thereof.

6. A- telephone system comprising a plurality of lines extending to a central office, means for impressing upon each line a charactcristic number oi electrical impulses for its identification, an extension circuit for said lines, a train of relays associated with said extension circuit, means for causing the successive impulses impressed upon an extended line to effect the operation of successive relays of said train, a signal associated with each relay and displayed in the opera- .tion thereof, and a locking circuit for each i in excepting the last oi the train to render the succeeding rrlay ol' the train responsive to ii'npulsus impressed upon said extended lin and nu'urzr controlled by each relay excepting the first of the train to render the preceding operated relay of the train in' H. in a telephone system, the combination with a. plurality of lines adapted for diii'cron? classes of service, oi moans l orcxtcnding any one of said lines to an operators posi- Lion. 'a clussoF-scrvicc idcntifving device laptcd to produce and apply to said lines diflerent and characteristic groups of impulses, signals and a series of signal controlling relays at the operators position, said relays being progressively energized and deenergized by the impulses of a group 7 toproduce an indication corresponding to the number of impulses in the, particular group that identifies the extended line.

9. In a call distributing system, the 001m bination with a connecting circuit, of counting relays operatively associated therewith, signals selectively controlled by said relays,

a plurality of lines of different characteristics adapted to be severally extended to said connecting circuit, and means assoso ciated with each line for impressing thereon a distinguishingnumb'er of identifying impulses for selectively operating said counting relays.

10. In a telephone system, the combina- 8 5 if tion' with an identifying commutator adapted to produce pick-up impulses and diflerent trains of counting impulses, of a plurality of terminating telephone lines to variously applied for the identification of,

said lines. an extension circuit for said lines, a group of counting relays, an energizing 1 circuit for the same, andvan electromagnetic avhichsa-id trains of countingimpulses are switch responsive to said pick-up impulses I i and adapted to control the operative relation of said energizing circuit With a telephone line;

11. In a telephone system, the combina- I i tion with identifving mechanism adapted to 10 produce pick-up impulses and different trains of counting impulses,of a plurality of telephone lines to which said trains of counting impulses are variously applied to identifv the same, an electromagnetic count- 10a ing device. an energizing circuit for the same adapted to he hrought'into operative connection with any of said telephone'lines and to he affected by the train of counting i m'pulscs flowing therein,and an electrically actuated switch responsive to said pick-pp iii-pulses and controlling the operative relation of said energizing circuit, with the associated telephone circuit.

F2. in a telephone system, the comhina- 11 tion with a circuit and a plurality of lines adapted to he severally extended thereto, of p an identifying device common to said lines and adapted to apply to the famous l1nes various numbers ofimpulses for their iden- 12 tiiication. a group of counting relays, s1gnuls controlled selectively by said relays,

and means for bringing saidcounting relays into association with said ClICllIlJ.

13. To a telephone system, the combina- -5 1 tion with a circuit and a pluralityo'l lines adapted to he severally extended thereto, of

a :1 identifying device common to said lines and adapted to apply to the various lines various numbers of impulses for their identification,

a series of electrically actuated signal devices adapted to be successively operated by successive impulses, means associated with each signal device and controlled in the operation thereof forrendering the preceding signal device in the series inoperative and means for bringing said series of signal devices into association with said circuit.

H. In a telephone system, the combina tion With a connecting circuit and a plurality of lines adapted to be severally ex-' tended thereto, of an identifying device common to said lines and adapted to apply to the various lines various numbers of im pulses for their i'dei'itification, a series of electrically actuated signal devices associated with said coi'inecting circuit, and means made operative by each of said Sig-- nal devices in its actuation to bring the next device in the series into operative relation with said circuit.

In witness whereof, l hereunto subscribe my name this 29th day of June A. D, 1915.

EDGAR HARRISON CLARK.

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