US1105492A - Telephone-exchange system. - Google Patents

Description

E. E. CLEMENT.

TELEPHONE EXCHANGE SYSTEM.

APPLIOATION FILED 001228, 1907. RENEWED APR. 28. 1914.

1,105,492. Patented July 28, 1914.

5 SHEETS-BHEET 1.

5] Wm 1 1 fez Wi in @9300 B. E. CLEMENT. TELEPHONE EXCHANGE SYSTEM.

APPLIOATION FILED 0012s, 1907. RENEWED APR. 28, 1914.

1,105,492. Patented July 28, 1914.

41 57 5 sums-$111121 2.

3] nuanfo'a wi tn zoom B. E. CLEMENT.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED 00w. 26, 1907. RENEWED APR. 28, 1914.

1,105,492. Patented July 28,1914.

6 SHEETS-SHEET 3.

atwonfoz E. E. CLEMENT.

TELEPHONE EXCHANGE SYSTEM. APPLIUATION FILED 0M. 26, 1907. RENEWED APR. 28. 1914.

1,105,492. Patented July 28, 1914.

5 SHEET HEET 4.

witnesses E. E. CLEMENT.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED OCT. 26, 1907; RENEWED ,APR. 28, 1914.

1, 105,492. Patented July 28, 1914.

5 SHBETSSHEET 5.

nuunfoz UNITED STATES PATENT OFFICE.

EDWARD E. CLEMENT, OF WASHINGTON, DISTRICT OF COLUMBIA.

TELEPHONE-EXCHAN GE SYSTEM;

Specification of Letters Patent.

Patented July 28, 1914.

Application filed October 26, 1907, Serial No. 399,283. Renewed April 28, 1914. Serial No. 835,046.

To all whom it may concern:

Be it known that I, EDWARD E. CLEMENT, a citizen of the United States, residing at Washington, in the District of Columbia, have invented certain new and useful Improvements in Telephone-Exchange Systems, of which the following is a specification, reference being had therein to the accompanying drawing.

My invention relates to telephone exchange systems, and has for its object the improvement of means for sending electrical impulses for the operation of automatic switches.

The systems in which sending devices are used are known ordinarily as the full automatic, in which case the impulses are generally sent from the calling subscribers station, or the semi-automatic in which a partial connection of the circuit is effected by means of a manual connective apparatus manipulated by an operator, and further connections are effected automatically by means of impulses from an impulse sending device. My invention is particularly applicable to the semi-automatic systems and it is designed to relieve the operator of a considerable part of the work necessary for the completion of the connection.

.An object of my invention is to reduce the time required to send the impulses for operating the automatic switches. Heretofore it has ben found difiicult to decrease the time for sending the impulses, since with the ordinary sending devices considerable time is necessary to allow for the running down of the mechanism after setting it up for the desired number. I accomplish this decrease in the required time by providing a constantly, operating impulse sending device and means for taking any desired number of impulses and projecting them upon the lines for o crating the automatic switches.

A "urther object of my invention is to relicve the operator of all further attention to the call after she has received the number wanted and has set the apparatus for sending the impulses. This is accomplished by means of a series of sending keys and of control relays associated with said sending device in the manner describedhereinafter.

l urthcr objects and advantages will appear in the detailed description of the in- \'(Illl0ll.

ll invention is illustrated in the accompanying drawings in which,

Figure l is a diagrammatical view of a subscribers sub-station and an operators cord-circuit; Fig. 2 is a view showing the vibrator and its associated relays; Fig. 3 is a diagrammatical view of the sending keys and the relays associated therewith; Fig. 4 shows a key set and relays identical with that of Fig. 3; Fig. 5 shows first and second selector switches and an automatic connector switch. Fig. 6, is a detail of the three position key in Fig. 4:.

Referring to Fig. 1, the subscribers substation is shown at A and it comprises the telephone set, including the transmitter T, the receiver R, the ringers Q, and the condensers C. The lines 1 and 2 lead to the central station and terminate thereat on the contacts 3 and 4 respectively of the cut-off relay D. The line relay is indicated at E and controls the signal lamp 30. On the actuation of the cut-off relay D the lines 1 and 2 are extended by means of conductors 5 and 6 to the terminal jack J.

The operators cord-circuit consists. of the plugs P and P normally connected by the conductors 7-8 and 910 through the con densers C and C respectively. The answering supervisory relay G is connected with the strand 7 of the cord-circuit, the other end of the winding being grounded. Associated with the supervisory relay is the signal lamp 37. The supervisory control relay I has one end of its winding connected to the strand 8 of the cord-circuit and the other end connected to the battery. A relay M is arranged to automatically connect the opcrators telephone set with the cord-circuit and cooperates for this purpose with the relay N. The operators telephone set consists of the operators receiver R in the secondary circuit a of an induction coil. The primary 1) is included in a short circuit with the condenser C" and the transmitter T, the latter deriving its current supply direct from the main battery through the choke coil L and ground. The tertiary winding 0 is included in a test circuit which will be describcd hereinafter. A switch K is provided to enable the operator to connect one of two key sets with the cord-circuit 2'. e. the one shown in Fig. 3 or that in Fig. 4 through the medium of the conductors ]1-12 or l3--14 respectively.

Tt will be understood that the operators manual connective means herein described is used merely as a typical connection link between the callin subscriber and the first selector switch. bviously the impulse'sending apparatus and its associated key sets could be used with automatic connection means such as primary and secondary selectors or relays adapted to connect the calling subscriber with the proper automatic switches for completing the connect-ion. Such sets are shown in my prior applications Serial Nos. 306,292 and 296,853'filed Mar. 15, 1906 and J an. 19, 1906, respectively. The operators cord-circuit is shown merely for the purpose of-rsimplifying the drawings, the invention lying in the means for sending: the "impulses necessary for operating the'automatic switches.

The trunk lines fi -16' which terminate in the jacks J- are each multipled to all sections of the switchboard so that any olperator can reach any trunk. Thetrunks are arranged in groups, those of each group leading to similar switches. in which the same group of subscribers" line-wires are multipled.

-Referring now to Fig. 2, V denotes in general avibrator comprising astandard 17 to which is lamp'e'd a sprmg member 18 having. an armature '19'attac'hed thereto and provided with spring contact members 20 and 21 adapted'to contact with their anvil's 22 and 23 respectively A weight24 is adj ustably movable along t spring 18 and provides means for regulating the rapidity of vibration of the latter. The magnet 25 when energized by means of the battery B attracts the armature 19 and moves the spring in the same manner as in the ordinary bell vi brator,=athe result being arrapid making and breaking of the circuit.

The two parallel rows of relays shown in Fig. 2 constitute,-together with the vibrator, the means by which the impulses are projected upon the lines for operating the automatic switches to eilect the desired connection. These relays by their joint action project one impulse on the first wire, two impulses on the second wire, three on the third, and so on up to the last wire'wllich finally receives ten impulses. 'After'this the relay set, the individual relays of which have locked after pulling up, is released by means of the relay R when the operation is again repeated, the vibrator and the "relays working continuously.

- The ten conductors shown at the top of ig. 2 lead to and 4. These key sets are composed of a series of keys in, k etc, of the so-called self-latching selective ringing type now in common use on manual switchboards, and employ the principle shown in the patent to Ham No. 605,097, granted June 7th, 1898. lVhcn any key is pressed down it remains in this depressed position until another key in the same set is depressed, when the first key ,in its depressed position.

' 0nd key k last key 10 provided" for Erickson i andthe second the key sets shown in Figs. 3

will be released and the latter will be locked As will be noticed from the figures-"the first key 7c of each set is-connectc'd with wire w,- the sec-' is connected with wire w the being connected with the last wire 40 Four keys, f, 7, f and f of the set K are provided'for party-line selective ringing and an extra key K is also provided for starting the impulses after the numbers have been set up. Two sets of relays operating similarly to those shown in Fig; 2'are the key sets together with their release magnet R 1111 Fig. 5 there is shown an automatic first" selector switch X, a second selector switch X'- and a connector switch These automatic switches are oft-he type shown and described in the patents to Keith and Nos. 815,176 and 8155321, granted March 13,1906. The first selector twitch selector switch are similar in construction and a description of the first selector will sufiice for both. -It consists in general of ashaft -S bearing wipers (l, e and g, the first two-being adapted to'etlect a connection of the talking circuit and the latter being a test wiper. The shaft is capable of both vertical and rotary movement, the former movement being reflected through the medium 043 the magnet 0 and the latter through the magnet W. These magnets are controlled by means of the-relays U and Y respectively while a side switch Z having movable arms 'z", 2 .2 and a is providedfor directing the successive series of imare provided for restoring the switch to its normal condition when conversation has ended.

The connector switch X is similar in construction to the selector switches but has in addition the ringing relay 'E controlled by thb commutator I and adapted 'to connect the generator G with the circuit for furnishing the ringing current. Talking current for the called subscriber is furnished through thewindings of the relays M and G", these two relays also serving in connection with therelav H" as control relays for the ringing relay E.

The operation of the system will be readily understood from the foregoing description of the apparatus used. Let us assume for purposes of illustration that the-subscriber at station A desires to communicate with another subscriber whose number 'is 4621. The subscriber at station A takes down his receiver, thereby closing the line circuit through the receiver hook. This en'- ergizes the line relay E. current flowing by the following path: battery B,QG,27,E,3,1. R, T, 2, l and ground. The armature 28 of pulses to the proper magnets in elliecting a I the line relay E then pulls up, putting battery on the conductor 29 whereupon the signal lamp 30 is lighted. On perceiving the signal the operator inserts the plug Pin the jack J. .The cut-ofi' relay D is thereby energized, current flowing by the following path: battery B, 31, I, 32, 8 P, j 6, D to ground. When the cut-off relay D pulls up, the'line wires 1 and 2 are connected with the extensions 5 and 6 respectively by means of the armat-ures 3 and 4, as a consequence of which the answerin supervisory relay G is energized current owing from battery .B, 31, I, 32, P, j 6, 4, 2, T, R, 1, 3, .5, j, 7, 33, G to ground. The attraction of the armature 3 breaks the circuit of the line relay E and the signal lamp 30 is thereby extinguished. The operation of the sleeve relay I puts ,battery current on the conductor 34 throu h the contact 35 by the branch wire 36. T e supervisory lamp 37 would therefore receive current through the contact 38 were it not for the fact'that the latter is attracted when the relay G is energized. When the relay I pulls up it energizes the relay M the energizing current being traced as follows: battery B, 31, 36, 39, 40, M, 41, 42 and ground.

The relay M bridges the operators talking set between the conductors 7 and 8 of the cord, by the following path: conductor 43 (wh1ch is connected with the strand 7,), contact 44, 45, the primary a of the'induction coil, R, 46, contact 47,48, the latter being connected with the strand 8. The operator, having learned the number of the subscriber wanted, depresses the number keys corresponding to the connection desired and inserts the plug P into the 'jack J leading to the first selector switch in the thousands group corresponding with the line wanted. Thereupon the relay N pulls up, cut-ting off the operators setand deenergizing the relay M, the actuating currentfiowing from B through 26, 31, 36, N, 36, p, 7' and ground. In case this particular trunk is busy, the o erator receives a click in the ear on touc ing the jack J with the plug P due to current through the tertiary winding 0 of the induction coil.

In case the system is provided with two sets of key banks the operator may make use of either set by means of the switch K. The provision of two sets is for the purpose of enabling the numbers to be sent with reater rapidity, for while .the impulses are fieing sent from one set the o erator can be using the other set to set up the numbers by merely shifting the switch handle K of another cord to one side or the other, thereby forcing the spring contacts :0. m against their anvils y and 71 and putting the conductors 11 and 12 or 13 and 14 in direct electrical connection with the cord-strands 9 and 10 by means of the conductors 49 and 50.

In case the operator desired to use the key bank shown in Fig. 3 she would shift the switch handle to the right, thereby con meeting the conductors 11 and 12 with the cord-circuit. These conductors appear in the lower right hand corner of Flg. 3, the conductors 13 and 14 appearing in the lower left hand corner of Fig. 4, the extensions 1 112 of the conductors 11--12 and the extensions 13'14 of the conductors 13-14 in Figs. 3 and 4 respectively being multiples leading to other cords.

Referring now to Fig. 2, V, as has been before stated, denotes a constantly oscillating vibrator. It will be observed that when the spring 20 is in contact with its anvil 22 current flows through the magnet 25 by the following path: B, 51, 52, binding post 53, 18, 20, 22, 54, 55, magnet 25 and ground. At the same time relay 1R of the set RA is energized the circuit being completed as follows: battery B, 51, 52, 53, 18, 20, '22, 54,

57, 58, contact 59, 60, IR and ground. The relay 1R then pulls up and locks, the locking circuit being from battery B, through 51, 52, c ntact 61 of relay R", conductor (52, 63, contact 64, G5, 60 1R and ground. It will be observed that t e same impulse that operates the relay 1R is placed on all the wires in the group from the conductor 57 through conductor 67 and the extra contacts 68 of all the relays in the group RB.

It should be here stated that the purpose of the groups of relays RA and RB is ,to automatically place one impulse on the first wire 1, two impulses on the second wire 2,, and so on up to ten impulses on the tenth wire 10. These impulses are not placed successivelybut are placed simultaneously and at each succeeding impulse one wire of the group is cut off from the current source. Thus all the ten wires receive the first impulse; the first wire 1 is then cut out and the nine remaining wires from 2" to 10 inclusive receive another impulse; then wire 2" is cut out and the remaining wires receive an impulse. Thus it will be seen that the first wire receives one impulse, the second two, and so on up to the last wire which receives 10. The manner in which this is done is as follows: When the magnet 25 is energized the armature 19 is attracted and the spring 18 effects a closing of the contacts 2123. This puts current on the relay 1R of the set RB over the following path: battery, 51, 52, 53, 18, 21 23, 56, armature'GG (which pulled up when the relay 1R was first energized), conductor (if), contact 70 of relay 2B. 71, 1B and ground. The armature 59 of the relay 1R on pulling up breaks the circuit of the relay IR and connects conductor 57 with the relay 2R through conductors 72, contact 73 of relay 2R and conductor 74. At the same time the relay IR is locked through the armature 75 on its opposite end, the locking -means of the same locking circuit traced in therefore, is actuated on the next impulse relay forms part of the locking circuits for the action being continuous.

circuit being from battery B, 52, 61, 62, 76, 75, 77, 71, 1B to ground. On the return of the spring 18 and the engagement of the contacts 20 -22, current from the conductor 57 energizes the relay 2R (over the path already traced) which pulls up and locks through the contacts 78 and 79 by connection with the relay 1R. At the same time an impulse is placed upon the wires 2 to 10 inclusive through the conductors 67 and 68. lit will be observed that since the relay 1R has pulled up and locked, its armature 68 has broken its connection with the first wire 1 of the group W This wiretherefore, does not receive the second impulse which is placed upon the remaining wires.

When the armature 70 of the relay 2R pulls up, it connects the relay 2183' with the wire 56 by means of the contact 66 of the relay 1R, conductor 69, contact 70 of the relay 2R, conductor 80, contact 81 of armature 3E and conductor 82. The relay 2R received by the wire 56 when the armature 19 is attracted by the magnet 25. When the relay 2R pulls up it is locked on the corn-i mon locking circuit traced in connection with the relay 1R and its armature 68 breaks the connection with the wire :2". This relay also places the relay 3R in electrical connection with the wire 57 by the pulling up of its armature 73. The relay 3B is now in condition to be energized when the next impulse is received from the wire 57 and the remaining wires in the group W' i. 6. wires 3 to 10 receive an impulse in the manner described. Similar impulses are placed upon the remaining wires of the group, one wire in each case being cut 0H and the two rowsof relays RA and RB locking as they are operated on the common locking circuits alrcadyj traced- The actuation of the relaylOR places the battery current on the relay 10R in the manner already described and the armature 83 or the latter on pulling up connects the release relay B3: with the wire 57 and puts it in condition tobe actuated by the next impulse on the wire 57. Tt will be noticed that the contact 61 of the release both the rows of relays RA and RE. The attraction of the armature 61 breaks this locking circuit and all of the relays let go, thereby restoring the relays to their original condition as shown in Fig. 2. The retraction of the armature 83 of the relay 10R. breaks the actuating circuit of the release relay and it also lets go. thereby. restoring the entire apparatus to its original condition group W and ready for another cycle of operations,

The last im- I pulse received from the wire 57 is piaced on a wire 84 by means of the contact 68 of l the relay 10R. The succeeding impulse from the wire 56 is placed through the medium of the armature 66 of the relay 1R (the latter having retracted after the release of the locking'circuit was broken), on a wire 85, these two wires 84.- and 85 being extended to the relay sets RC and RD of Fig. 3 on to the relay'sets REand RF of Fig. 4. This impulse onthe wire 85 is in reality. the start ing impulse for the control relays associated 'with the. key sets and should be considered as the necessary impulse preceding the next cycle, not as an impulse following a completed cycle.

Referring to- .Fig. 3, the wires of the are shown extended from Fig. 2

to their connections with the key banks.

The means by which the impulses are taken from the wires VV and placed upon the cord conductors by means of the key sets is as follows: I have assumed that the operator has set up the numbers 4621.. She

'now depresses the starting key K Current flows from battery B through conductor 86, 87, contactsp- ring 88, 89, 90, relay 1R of the set RD and ground. The relay-1R having pulled up, .the wire .85 is connected with the relay 1R through conductor 91, contact 92,93, 94, 95, 1R and" ground. At the same time it locks, the locking-circuit being from battery through 86, 87, contact 96 of the release relay R conductor 97 contact 98, 90, IR and ground. Associated with the relay llt is an extra contact 99 connected with the conductor 100. When this armature pulls up it puts the battery current on the guard lamp L by the followin path: battery, 86, 101, L 100, 99, 102 an ground. The guard lamp thereupon lights up and indicates to the operator that the numbers are being sent. lltwill be noticed that this lamp does not light up until the relay 1R has been actuated by the closing of thestarting key K- 39', 100, 99, 102 and ground. The. pulling up of the armature 92 of the relay 1R as has been stated energizes the relay 1R This connects the wire 84 with the relay 2R through 103, contact 104:, 105, 100, 107, 2B

and ground, and places the relay in condition for actuation at the succeeding impulse on the wire 84. The attraction of the armatrue 104 also connects the wire84 with the wire 11 leading tothe sleeve side of the cord-circuit through I The relay IR is locked, the locking cirthe conductor 108.

'cuit being from battery through 86, 87, 96,

.101, 1,015, 106, 127,-128 and 129.

97, 109, 110, IR and ground. The armature 111 on pulling up places one side of all the contact keys in the set K 9 on the wire 12 leading to the tip side of the cord-circuit through the conductors 112, 111, 113, 114, 115, 116, 117, 118, 119, 120 and 121. The key is in the set K having been depressed, the wire 4 is connected with the wire 12 over the path traced and four impulses are placed upon the wire 12 and through the latter upon the trunk line 15 leading to the first selector switch X.

Referring again to the set RD, when the.

second relay 2R of this set pulls up (the energizing circuit of which has been already traced), it is locked on the common looking wire 97 by one of its armatures 122 in a similar manner to the locking of the relay 1R3 by the actuation of the armature 98.

. The other armature 94, of the relay 2R, on

pulling up connects the wire 85 with the relay 2R through conductor 91, 92, 93, 94,

' 123, 124, E5, 2R so that when the succeeding impulse is placed on the wire 85 the relay 2R is actuated. It is locked on the common locking circuit 97 through the pulling up of its armature 126 in a manner similar. to the locking of the first relay ofthe set BC. The pulling up of its armature 106 connects the relay 3R of the set RD with the wire 84 through conductor 103, At the same time the movement of the armature 106 breaks the actuatingv circuit of the relay 2R the actuating circuit of the relay 1R having been broken in the forward movement of the armature 94 of the relay 2R The armature 114 of the'relay 2R on pulling up connects one side of the key contacts of the key set K with the wire 12 through its engagement with the front contact through conductor 130 and the remainlng path already traced in connection with key set K 9. The action of the remaining relays 3R 41R and 5R 311-,411 and ER is simply a repetition of the action of the.

relays 2R and 2R respectively. It has been shown how the relays IR and 2B of the set BC in co-action with the first three relays of the set RD place the conductors 112 and 130 leading to the key sets K and K respectively, in successive connection with the wire 12 leading to the tip side of the cord-conductor and-thenee on to the a corresponding trunks leading to the automatic switches. In like manner the pulling u of the armature 116 cuts oil" the kc sets 15 and K from connection with the wire 12 and connects the third set K and the armature 118 of the relay 4R connects the set K. The last relay of each set serves to connect the fifth set of keys K for the purposes of selective ringin where the impulse sending device is to used in connection with a party-line system, The pullthereby releasing all of the relays of both sets and restoring them to their normal position as shown in Figs. 3 and 4, leaving them ready for further actuation when the starting key K is again depressed.

It will be remembered that at the beginning of the operation of the relays of the set RA in Fig. 2, one impulse is placed on the Wire 85 through the conductor 56 leading to the vibrator and through the armature 66 of the relay 1R of the set RA and that one impulse is finally placed on the wire 84 by the pulling up of the armature 68 of the relay 10R 01' the set RB, this im ulse being derived through the wire 57 leading to the other side of the vibrator. It has also been shown how the wire 85 furnishes the actuating current for the set of relays RC which control the circuits leading to the key sets, while the wire 84 is connected at the first actuation of the relay 1R directly to the wire 11 leading to the sleeve side of the cord and thence to the automatic switches. Bearing this in mind it will be apparent that after the numbers 4621 have been set up in the manner described and the starting key depressed, the first impulse placed upon the wire 85 and actuating the relay 1R will send four impulses from the wire 4 through the closed contact of the key It and conductor 112 to the wire 12 and thence to the trunks leading to the automatic switches. This having occurred, a single impulse coming on the wire 84 will be placed on the wire 11 leading to the sleeve side of the trunk, but this same impulse, as has been before described, puts the relay 2R in condition to be energized (through the pulling up of the relay 2R) which places six impulses from wire 6 through the closed contact 7c of the set K on the wire 12 lead' ing to the tip side of the trunk. Following this comes another impulse on wire 84. In like manner two impulses are sent from wire 2 -through the closed key In when the relay 3R pulls up, followed by a single impulse from the wire 84 to the sleeve side of the trunk, and one impulse from the wire 1 on wire 12, with one final impulse on the wire 11. Incase the party-line keys are to be used the key depressed will place a corresponding number of impulses on the tip side of the trunk with a final impulse from the wire 84 on the sleeve side.

In Figs. 3 and 4 I have shown branch wires 87 and 90 leading from the starting'wires 87 and 90 to a master contact m controlled by the locking bar of the key set K through the switch S This provides a means for sending the numbers evenmore rapldl than when the starting key K is used. T e latter key, it will be remembered, is depressed after all of the numbers have been set up. Ordinarily the calls can be answered readily by using the starting key K but during the busy portion of the day the-operator may want to increase her speed.- She therefore shifts the handle of the switch Sf thereby H time of one second before the control relays connectthe succeeding key set 1 withthe lines. In order to keep ahead of the control relays which send in, the numbers the operator must set up the four numbers. in four seconds or less; As an expert operator can do this with ease it will be readily seen that time will be saved by starting the impulses with the depression of the first number key.

After the busy time has passed and'the calls begin to come in more slowly the operator will. not need to set up the numbers so.

rapidly and she can break the circuit at the switch S and again make use of the starting key K asbefore. v

' In the preceding paragraphs I have shown how the actuating impulses are taken from the wires upon which the impulses are being continuously placed by means of the vibrator. These impulses are intended to operate the automatic switches for efl'ecting connection between the two subscribers, and

- while I have shown in Fig. 5 automatic switches of the particular type heretofore mentioned it is to be understood that any type of automatic switch operating by selective impulses may be substituted for those herein shown. While therefore, I shall ,de-

scribe the working of these switches in detail it is for the mere purpose of better illustrating the uses to which my invention can be put.. I v t l Referring now to Fig. 5, the first four impulses coming over the trunk wire 15 cause the actuation of the relay U, current impulses flowing from the trunk wire 15 through the switch arm .2 132, U, 133 and ,to ground. The armature of the relay U on pulling up closes the contacts 134, 135, thereby energizing the vertical magnet 0 through .the following path: battery, 26, 136, 137, U, 138, 139, 140, 141, 134,135, and ground. The

menace four impulses on the magnet d cause the spindle S to step up to the fourth row of contacts. One impulse from wire 11 is now received over the sleeve side of the trunk 16 through the switch arm 2 conductor 142, relay Y and ground. The relay Y, pulling up for a moment, closes the contacts 143 and 135 therebyenergizing relay Z, controlling the side switch, through the following path: battery, 26, 136, 144, relay Z, 143, 135 and ground. The actuation of the relay Z turns the switch arms a, z? and 2 one step. This results in the cutting off-of the relays U and Y and the actuation of the relay WV, current flowing by the following path: battery B, 26, 136, 144, 137, 145,.W, 146, z" and ground. The relay W is a make and breakdevice as indicated by the diagram. It controls the rotary action of the spindlefS and at each impulse turns the latter one step, the test wiper g sweeping-along the test contacts g to find an idle trunk leadingto a second selector switch. If the first trunk encountered 136, 144, Z, 143, 147, contact 148, switch arm e, 149, H, 150, g, g, and through the corresponding contact of the busy switch connected in multiple with the contact g, back over the wiper of the busy first selector switch corresponding to g and to ground through the relay corresponding to the relay H and the switch arm 2 which is resting on the third contact in the selector switch of the busy trunk. The relay Z is wound to a high resistance while the relay H has a low resistance. When the two are in series as in this test circuit just traced, the relay Z is energized while the relay H is not. As long as the wipers g find busy trunks this test circuit is maintained and hence the relay Z is kept energized. I When however, an idle trunk is found the test circuit is broken, the armature of the relay Z drops back and in doing so-it moves the switcharms e, 2 etc., to their third position. Themovement of the switch arm ya to its third position cuts oif the rotary magnet W thereby bringing the switch to rest. The movement of the switch arms .2 and 2 close the talking circuit of the switch, while the movement of the switch arm 2 places the release magnet F in condition to be energized at the end of conversation. The first selector switch is now connected with the trunk leading to the second selector switch X. Six impulses are now received by the relay U and the spindle of the second selector switch is stepped up to the sixth row. A single impulse from the j wire 11 is received by the rotary relay Y thereby actuating the side switch Z starting the rotary magnet 'W in a manner similar to that described in connection with the first selector switch. This starts the-spindle S rotating and it continues to do so until it finds an idle trunk leading to the connector switch X when the wipers d and 6 will effect connection between the trunk received by the relay U thereby actuating the vertical ma et 0 and stepping up the connector switc to the second row. The single impulse on the relay Y operates the side switch Z in the manner described and places the rotary magnet W through the shifting of the switch arm a to its second position, in condition to be energized on a subsequent actuation of the relay U One impulse is now sent from the key set K in Fig. 3 which acting through the relay Y closes the contacts 151, 152 and operates the magnet W thereby turning the switch spindle S to the first contact in the row, the actuating current being over the following path: B, 26, 153, 154, 155, magnet W con: ductor 156, contact 157, 2, 158, 159, 160, 151, 152 and ground. The Wipers d and 6 now rest upon the contacts leading to the called subscribers line. This places the relays G and the cut-off relay of the called subscribers line, in series and they both pull up, the energizing current being from, battery B, 26, 163, G, 164, 165, contacts 166 and 167, 168, 2 169, e", sleeve sideot subscribers line out-ofi' relay and ground. The ulling up of the armature 170 of the relay (E places battery on the ringing relay E when the constantly rotating commutator I is in its conducting position, as follows battery, 26, 163, 171, 170, 172, contact 173, 174, E, 175, commutator 'I and ground. This current actuates the relay E intermittently, each actuation of said relay projecting ringing current from the generator Gr as follows: G, 176, 177, through the wiper d and by the tip side of the subscribers line throu it his ringer, returning by the sleeve side an wiper 0 168, 167, and 178. When the subscriber answers, his line circuit is closed and the relays G and M are placed in series, the talking current flowing from battery throu h the relay G and the sleeve side of. the su scribers line back upon the tip side and to ground through the relay M. The latter then pulls up its armature 179 thereby energizing the relay H, the energizing circuit being as follows: battery, 26, 163, 171, 170, 180, 187, 179, 192, H 183, and to ground through the closed contacts 162 and 161, the latter bein closed by the first upward movement of t e spindle S The actuation of the relay H breaks the energizing circuit of the ringing relay E by the movement of its armature 173. n

' In case the called subscriber is busy a test circuit is established either through the relay of the busy connector switch corres ending to the relay M, or (if the called su scriber had originated the previous call) through the relay of the cord-circuit corresponding to the relay G. In the first case the circuit would be traced from battery through 26, 153, 18 1, relay H ,185,186, 187, 188, 189, 190 and 191, switch arm 2", 192 and on the sleeve side of the connector switch through the sleeve relay corresponding to M onto the rough the relay correcord-circuit and t sponding to the relay G. In either case the actuation of the relay H puts battery on the release magnet F the circuit being from battery through 26, 153,193, 194, 195 and ground. The release magnet releases the spindle S and restores the connect r Switch to its original osition. Ordinarily this would connect a usy back Si nal with the trunk wires leading from t e connector switch to the second selector switch and thence back over the line to the calling subscriber thereby ivin him to understand that thecalled su scriger is busy. In either case, whether hefinds the line busy or after conversation with the called subscriber (in case his line was not busy) the calling subscriber hangs up, thereby placing an impulse on both the bridged relays U 'and Y their simultaneous action causing a closure of the contacts 196 and 197. This places the relays H and H in series, the current flowing by the path B, 26, 153, 184, Hi-185, 197, 196, 198, g, 199, H, 200, 2, contact 201 and ground. The connector switch is released as efore d ribed and theoperation of the relay H closes the ontacts 202 and 203 leading to the release magnet F of the relay X putting the latter in series with the re a H of the first selector switch X, current owing through the magnets by the following path: batter 26, 204, 205, F, 206, 203, 202, 207, g, 150, 149, z, 208, and ground. The actuation of the relay F releases the second selector switch and restores it to its normal con hile the actuation of the relay H closes the contacts 209 and 210 and establishes a release circuit for the magnet F, said release circuit being from battery through 26, 136, 211, F, 212, 210, 209, 213 and ground. This releases the first selector switch and restores it to its normal condition. The breaking of the circuit at the subscribers substation de'clner izes the supervisory relay G thereby esta lishing a circuit through the lamp.37 from the battery through 31, 36, 35, 34, 38, 37, and ground. The operator receiving the clearing out signal withdraws the plugs P and P from their jacks thereby restoring the whole system to its normal con dition.

Having thus described my invention what I claim as new and desire to secure by Letters Patent of the United States is:

1. An impulse sending device comprising the following instrumentalities: a group of impulse transmitting conductors, a common vibrator furnishing impulses thereto, and means to govern said impulses in recurring cycles so as to supply a predetermined distinctive number of impulses to each conductor in each cycle.

2. An impulse sending device comprising the following instrumentalities: a group of impulse transmitting conductors, a common vibrator furnishing impulses thereto, means governing said impulses in recurring cycles so as to supply a predetermined distinctive number of impulses to each conductor in each cycle, and means-for selectively connecting a said conductors with a transmission circuit. 8. An impulse sending device comprising the following instrumentalitiesz a group 0t 7 impulse transmitting conductors, a common vibrator furnishing impulses thereto, means governing said impulses in recurring cycles so.

as to supply a predetermined distinctive number of impulses to each conductor" in each cycle, and-a set of switching devices corresponding to and connected with the respective condpctors and adapted to selectively con nect the same to a transmission circuit.

4. An impulse sending device comprising sponding to and connected with the respec-,

tive transmitting conductors each adapted when operated to connect its conductor with a transmission circuit.

5; An impulse sending device comprising the following instrumentalities: a group oi impulses transmittin conductors, a single ev1ce therefor, means impulse producing distributing the impulses from said dev1ce in recurring cycles so as to supply a predetermined dlstinctive number'of impulses to each of said transmitting conductors during each cycle, switching means associated with said conductors and adapted to selectively connect the same with a transmission circuit, and means to produce successive selective transmission during a plurality of cycles.

(5. An impulse sending device comprising the following instrumentalities: a group of impulse transmitting conductors, a single impulse producing device therefor, means distributing the impulses from said device in recurring cycles so as to supply a predetermined distinctive number of impulses to each of said conductors during each cycle,

means corresponding to and connected with the'respective conductors adapted to connect them to a plurality of branch transmission wires, and means i'or connecting one branch said impulse receiving ioness after another to a main transmission circuit durmg successive cycles, whereby a definite predetermined number of impulses will be transmitted for each cycle over said maincircuit.

7. A calling device comprising the follow-' ing instrumentalities: a constantly actuated impulse sending device, a group of impulse receiving conductors,and step by step relays adapted to place upon said conductors a constantly recurring series of impulses, the impulses received by each conductonvarying in number fromthose received by any other conductor of the group.

8., A calling device comprising the following instrumentalities: a constantly actuated impulse sending device, a group of impulse receiving conductors, a series of groups of contact keys associated with said conductors, means for placing upon said impulse receiving conductors a constantly recurring series of impulses varying in number with each conductor of the group, and means for bringing into operation each group ofcontact keys successivelyand for'placlng upon a trunkor transmission line impulses from any selected impulsereceiving conductor.

9. A calling-device comprising the following instrumentalities: a constantly actuated impulse sending device, a group of impulse receivin conductors, a series of groups of contact eys associated with said group of impulse receiving conductors and adaptedto connect the latter with trunk" lines, controlling means for bringing 'each groupbf keys .into operation successively, and means for placing upon said group of impulse receivmg conductors. impulses varying 1n number with each conductor and for actuating said controlling means.

v10. A calling device comprising the following instrumentalit-ies: a constantly ac tuated impulse sending device, a group of impulse receiving conductors, a series of groups of contact keys adapted to connect the latter with trunk lines, controlling re: lays for bringing the groups of contact keys into successive operation, and a series of step by step relays adapted to place a constantly recurring series of impulses upon conductors and to furnish actuating impulses tor the operation of the control relays. 11. A. calling device comprising the following instrumentalities: a constantly act ing impulse producing device, a group of impulse connected-with trunk lines, a series of relays corresponding in number to the impulse receiving conductors, and a second series of relays cooperating with the first series to place upon said impulse receiving conductors a constantly recurring series of impulses varying in number with each conductor of the receiving conductors adapted to be Mill) too 12. A calling device comprising the following instrumentalities: an impulse sending device, impulse receiving conductors, key sets for connecting said conductors with trunk lines, control relays for bringing said key sets into operation, means forplacing an impulse simultaneously upon all of the impulse receiving wires, and means to thereafter cut off the individual wires of the group one by one in succession, at each step placing a simultaneous impulse upon all the remaining wires.

13. A calling device comprising the following instrumentalities: an impulse sending device, a group of impulse receiving conductors, and a plurality of groups of coacting relays arranged to place upon the impulse receiving wires a constantly recurring series of impulses, the first wire receiving the lowest number of impulses and succeeding Wires receiving progressively increasing numbers of impulses.

v14. A calling device comprising the following instrumentalities: a constantly actuated-impulse sending device, a group of impulse receiving conductors, a plurality of groups of co-acting distributing relays adapted to be actuated by the impulses from said sending device and to pull up and lock on a common locking circuit in step by step order, and a release relay controlling said common locking circuit and arranged to be actuated in the movement of the last relay of one of said groups for releasing all the re lays and restorin them to their normal condition whereby t eir operation is constantly and automatically repeated.

15. An impulse sending device comprising as its essential elements a constantly acting periodic circuit changer, and a plurality of coacting relays adapted to be set up in successive order so as to govern the transmission of impulses from said circuit changer.

16. A multiple circuit impulse sending device composed of a single circuit changer imd a plurality of coactmg distributing reays.

17. An operators control apparatus for signaling systems comprising an impulse producing device, a plurality of selective devices, means for startin the transmission of impulses in the actuation of said selective devices, and alternative starting means separate from and independent of said devices, together with means to render the first means operative 'or inoperative at will.

18. In a system of selective impulse transmission, an impulse producing device, selective switching means cooperating therewith to determine the number and grdup relation of impulses to be transmitted, a manual key, starting means actuated thereby to cause transmission of the impulses selected,

alternative starting mechanism automatically actuated in the operation of the selective switching means, and a disabling switch for said alternative starting mechanism.

19. In a system of selective impulse transmission, an impulse producing device, selective keys for determining the impulses to be transmitted therefrom, a connection therefrom to the main transmission circuit, a starting relay,-a starting key controlling said relay, and starting contacts also controlling said relay, operated in the actuation of the selective eys.

20. In a system of selective impulse trans mission, an impulse producing device, selective keys for determining the impulses to be transmitted therefrom, a connection therefrom to the main transmission circuit, a

starting relay, a starting key controlling said relay, starting contacts also controlling said relay, operated in the actuation of the selective keys, and a switch controlling said contacts, adapted to connect the same to and disconnect them from the starting relay at will, whereby rapid operation may be had by closing said switch, without using the starting key. 4

21. In a system of selective impulse transmission having automatic switches and means for producing working impulses therefor, selective keys for determining the number of impulses to be rendered effective on the switches, a transmission circuit eX- tending from the keys, a plurality of branch circuits includin contacts in the individual keys adapted to e closed when the same are actuated and selective switching means acting synchronously with and in obedience to the impulses in the transmission circuit to test the keys in succession in order to determine selectively which key has been actuated, and means to stop the transmission of impulses, and thereby to stop the movement of any automatic switch then in circuit, when said key has been reached.

22. In a system of selective impulse transmission, means for producing impulses, se lective keys for determining the impulses to be transmitted therefrom, a transmission circuit, starting means controlling the operative continuity of the transmission circuit, a circuit including said starting means, and starting contacts in said circuit, vassociated with and operated in the actuation of the selective keys, whereby the setting of the keys to determine the number of impulses will automatically start the transmission of the same.

, In testimony whereofI afiix my signature 'in presence of two witnesses.

EDWARD E. CLEMENT.

Witnesses PEARL THWAITE, E. EmroNsroN, Jr.

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