US974955A - Automatic telephone system. - Google Patents

Description

A. H. DYSON.

I AUTOMATIG TELEPHONE SYSTEM. trunnion 3mm nov. 2a, 100".

Patented Nov. 8 1910.

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A. H. DYSON. AUTOMATIC TELEPHONE SYSTEM. LPPLIQATIDN IILHD NOV. 83, 1907.

Patented Nov. 8,1910.

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A. H. yson; AUTOMATIC TELEPHONE SYSTEM. APPLIOLTION FILED NOV. 23, 1907.

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' A. H. DYSON. lUTOMATIG TELEPHONE SYSTEM. APELIOATION FILED NOV. 23, 190i!- Patented Nov. 8, 1910.

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Original application filed November 13, 1906, Serial No. 343,255. Divided and this application filedNovem- UNITED STATES PATENT OFFICE.

ALFRED H. DYSON, OF CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS, TO KELLOGG SjWITGHBOABD & SUPPLY COMPAIIY, A CORPORATION OF ILLINOIS.

AUTOMATIC TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented Nov. 8, 1910.

ber 22, 1907. Serial No. 403,527.

To all whom it may concern:

Be it known that I, ALFRED H. DYsoN, a citizen of the United States, and resident of Chicago, Cook county, Illinois, have invented new and useful Improvements in Automatic Telephone Systems, of which the following is a specification.

This ap lication is a division of my application filo; 343,255, filed November 13, 1906.

My invention relates to telephone systems ofthe specified character wherein a plurality of selective switches are employed successively in completing each connection.

In the'system WlllCll I show in the accompanying drawings, first selector, second selector and connector switches are employed, and in addition, switches of a fourth class which I term line selectors, the said line selectors being each connected to a first selector and having the function of temporarily associating the first selector with the calling line by means of automatically controlled apparatus. 1

An ob ect of my invention is to provide means included in the telephone system for registering the number of calls made over each line, as a calling line, to which a response of the called subscriber is received. This I accomplish by associating with each line selector mechanism, a printing magnet actuated when thecalled subscriber answers the call, together with an adjustable typeframe which may be automatically adjusted by the operation of theline selector in connecting to the calling line so as to bring a type, bearing the number ofthe calling subscriber, into operative relation to the printing magnet. v

The above, with other advantages of my improved system, will appear and be pointed out more specifically in the detailed description of the drawing and in the claims.

Figure 1, comprising parts 1, 2 and 3,

illustrates diagrammatically a preferred cir-.

cult arrangement; Fig. 2 is a front-view of a. master-switch; Fig. 3' is a side-view there of'; Fig. 4 is a sectional View of a line selector, showing particularly the primary magnet .and its associated mechanism; Figs. 5

and 6 show a first selector'release magnet and associated mechanism; Figs. 7 "and 8 show top views of an over-run and primary off-normal switch, respectively;Figs. 9, 10,

and 11 are respectively left, front and right elevations of a line selector. Figs. and 14: show similar elevations of a connec; tor. Fig. 15 is a top-view of the registering mechanism of my invention.

Referring first to Fig. 1, the system there illustrated may be considered as aten thousand line system. Assumingsuch to be the case, each subscribers line such as those' of substationsA and B, extends to the exchange and is there provided with its; individual passive multiple line contacts 20, 22 and 2ft appearing with those of ninety-nine other lines in the contact banks of ten line selec:

tors such as D. Inasmuch as ten. thousand lines are assumed, there will have to be in all one hundred such groups of lines, each with its ten line selectors, making a total of one I thousand such selectors. Each such line sel'ectorhas permanent conne'ctionlwith a particular first selector suchas E, which is antomatically brought under thetcontrol of currents to be sent over the calling line by the operation of the line selector D. The first selector by its adjustable wipers, gives the calling subscriber access to one hundred second selectors, there being ten of. these representing each one thousand lines of the exchange. Gontacts of the second selector engaged by the first selectors, are, o;t course, multipled in the usual manner, to a large number of first selector contact banks and would ordinarily be multipled one hundred times or to one hundred such banks. j

Responsive to currents transmitted over the calling line by the subscriber, the first selector is caused to select the group of second selectors corresponding to the one thousands digit of the called number; the first selector then'automatically selects the-first vided in ten groups of ten switches each, the,

switches of each group being adapted to select out any particular line of a onehundred line group of subscribers to which the switches of the group are assigned. The contact terminals of the connectors are, of

course, multipled alarge number, of times and would ordinarily e multipled in the present 5 stem one hundred times or to each second so ector of a one thousand line group.

Tlie second selector operating responsive to I currents controlled at the calling substation, selects the group bf connectors desired, and then the idle connector, thereby placing it at under the] control of the calling substation. Tl. co lube-tor, by its wipers, has access to ,contact forming multiple terminals of subiscriber lines forming a one hundred line group, said. contacts being multiplied ten times to appear in the contact banks of ten connectors. i In a1 ordinarily busy exchange of ten thousand lines, one thousand line selectors ,with their one thousand first selectors, one ;thousapd"second selectors, and one thousand lconnec .ors, would be adequate to handle the business of the exchange.

As above indicated, line selector D by ,1 means? of its wipers has access to one hun- 26 dred sets'of multiple contacts 20, 22 and 24 forming terminals .01 a group of one-hun dred subscribers lines. The contacts'of these lines are preferably arranged in ten groups of ten contact sets each, the motion of the 25 wipers of switch D being first in a. primary direction in on: plane to select a group of contacts, and then ina secondary direction in another plane to select the calling line 0 the group. Each group of ten lines therefore, has a common or group contact 26 controlled by a common relay 18, which contact the wiper 27 engages. The said wiper 27 controls the primary movement of the switch D, the line wipers-21, 23 and 25 moving 5 along with the said wiper 27. When the wiper 27 reaches a group contact 26 belonging to a group of lines among which a call ing line is included, the primary movement of all the wipers is arrested and the line wipe-rs 21, 23 and 25 then initiate their secondarymovemenls to select the individual contacts 20, 22 and 24 of the calling line, wiper 27 remaining quiescent at this time and not partaking of the secondary move- 11 ment.

As before stated, each group of one hundred calling lines has associated with it ten line selectors D, so that, the contacts 20, 22 and 24 of each line and the group contact 26 of each group is mult-iplecl ten times, once to each such line selector bank. When the,

calling-subscriber removes his receiveryhe causes a line selectortostart into operation to seek out his lineand thereby 'connect the first selector with said line.

through the agency of the master-switch C to whose relay 28 each calling line is enabled to Lausmit current by means of the switch gontacts of its line relay 9. The said masterwitch when operated at the initiation of a call as above indicated, causes an idle line selector to start its operation. The line selector then re-acts'upon the master-switch in such manner that its wip rs 30-34 move 5 away from the switch contacts 3135 of the This is effected.

line selector which they start, and then keep up an independent progressive movement via terminals 3 '35 of busyline selectors until they reach terminals of an idle one, when the said wipers come to rest. The detailed relation of the different parts to one another will be best understood through the narrative of operation.

Assuming that subscriber A is to be connected with-subscriber B whose telephone number will be assumed to be 3456, subscriber A, first removes his receiver thereby completing a conductive bridge of limbs P and S by the usual elevation of the hook lever. Relay 9 from ground therethrough, normal armature contact 14 over limb P through hook lever and transmitter at station A, limb S, normal armature contact 16, to battery B. Armature 10 is thereby attracted to engage its switch contact, (immediately thereafter breaking the normalcontact' of said. switch contact whereby substation control of relay 9 is removed) to complete a locking circuit for" said relay established from ground therethrough, contact 10, contact 17, relay 18, to battery. Relay 18 attracts its armature to remove group contact 26 at each line selector of the I ten. Armature 11 disengages its normal contact to remove ground from each of the individual private contacts 20 of the line at the ten line selectors, and the. said armature engages its alternate contact operatively connecting relay 12 with the contacts 20. The lower armature of relay 9 engaging its contact, completes a circuit from ground through resistance l9,'the left-hand winding of tery, causing said'relay to attract/its armature. and complete an energizing circuit of relay 29 which latter attracts Its armature and causes a flow of current as follows: from ground at its armature through con tacts 3031, contact 40, at an idle line solector D (wiper 30 when resting always enhereafter explained) through relay 37 of said line selector to battery. Relay 37 attracts its upper armature and closes circuit from ground through resistance 36, righthand winding of relay 28 to battery, whereby the armature of relay 28 is allowed to fall back, because the said relay is'difierentially wound, and resistances 36 and 19 are equal. It is apparent that relay 29-is thereon. immediately armature retracted. Armature 39 of relay 37 is attracted closing circuit through vibratory primary magnet PM, which becoming energized,.'advances wiper 27 to engage the first group contact 26, Wipers 2 1, 23 and 25 moving opposite the contacts of the first group but not engaging any contacts. Relay 37 has attracted its armature 38 and; if

ground from the multiple' master-switch relay '28 to batgages contact 31 of an idle line select-or as,

deenergizedand its is energized by current/ v '27'to engage the the first group contact 26 engaged is in its normal condition, no line in the group then calling, the said contact will be grounded at the armature of grou ing circuit is completec for relay 37 from ba tery through said relay, attracted armature 38, contact 27-26 to ground via armature of the first group relay 18. As armature 39 thus continues PM is, on the retraction ott its vibratory armature, again energized and moves wiper second group contact. If this contact has its normal ground at the second group relay 18, relay 37 will continue energized and the preceding process is repeated; wiper 27 engaging the third group contact 26; and so on until the group contact of a calling line, that of subscriber A, is found whose ground hasbeen removed by the previously described operation of relay 18. No locking circuit for relay 3? is tact 26 of the the original energizing circuit of relay 37.

then completed and its armatures are'retracted, the armature 39 preventing further operation of primary magnet PM Whereby wiper 27 rests engaging group conten line group including line A, while line wipers 21, 23 and 25 have moved along with wiper 27 to such a posi tion that they are ad acent to the group of contacts including a line contact set of subscriber A. a

On the first primary movement of the wipers, contacts 10l1--42 of the primary ofl -normal switch P.O.Sw were shifted to their alternate positions, contact 40 opening Contact 41 completes a circuit from ground, through contacts 34, relay 32 to battery B causing relay 32 to attract its armature whereby circuit is completed for magnet 33 of the master-switch, which, by its energization, advances wipers 30 and 34L a step to engage contacts 3135, respectively, of thenext line selector, it being understood that the said wipers have in front of them ten contacts 31 and ten contacts 35, belonging in pairs to ten line selectors. If the contact 35 now engaged by wiper 34- belongs to a busy line selector, that is, one in which spring 41 has been shifted, relay 32 will continue energized by current from this second line selector-via its shifted spring 41 magnet 33 Will step wipers FED-34 one step farther, when the above process will he rc peated'if that line selector is in use, and so on until Wiper 3% engages contact 35 of an idle line selector, when its contact 41 will be as shown at D, namely, on open circuit whereupon relay 32 will become dci nergizcd preventing further operation of magnet 33, and wipers 30 and will remain on the contacts of an idle line selector waiting for another call to come in.

Returning now to primary otflnormal switch contact 42, its shifting operatively relay 18, and lock cuit is completed from ground attracted, .magnet movi'ng wipers 212325 to 34 of the master-switch connects the Winding of relay 48 with the normal contact of the upper armature of relay 37, so that on the denergization of said-relay occurring as before described, cirat said upper armature, through contact -12, normal contact 1-5, relay 18 to battery B.- Relay 4:8 is there by energized to initiate the secondary more ment-ot wipers 21, 23 and 25 by means of its armature 51 which closes circuit from battery through secondary magnet SM, armature contact 51, tov ground through alternate contact of switch spring 46, springs et(it7 of the release switch RS112 having been previously shifted on the first energization of primary magnet PM. Wipers 21-23 25 engage contacts 2O -2224; respectively, belonging to the first line of the group. When it is at normal, that is, when the sulr scriber is not making a call, its multiple con tact 20 will be grounded by way of the normal contacts 11 and 15 of its relays 9 and 12; hence, armature -50 of relay 48 being at this time attracted, a locking circuit will be closed from grounded contact 20, Wiper 21, attracted armature 50, relay 18 to battery and armature 51 continuing attracted, secondary magnet SM, will, on the retraction.

of its armature, become agaln energized engage contacts 2O2 2'24t of the. second line of the group. If this line is not calling, its contact 20 will be grounded and relay 48 will continue to be locked as before described, a third de'energization and energizatioh of secondary magnet SM resulting, advancing the wipers the third secondary, movement, and so on until contact 20 of the line of subscriber A is reached, which contact on account of the attracted condition of arma.- ture 11 of relay 9, is ling-rounded, whereby locking circuit of relay 48 is destroyed, its armature retracted, opening circuit of secondary magnet SM and preventing further movement of wipers 212325 which remain in engagement with the multiple contacts of the calling line. 52 were held attracted during the secondary movement of the wipers in order that wipers 23 and 25, which were then wiping over line contacts of the various lines, might be insulated so that no disturbance of existing conversations could oc'cur. Upon the deenergization of the relay 48, they will of course be retracted to extend wipers 2325 to connection with the circuits of the first selector E. Contact 50, upon the dciinergization of the relay, falling back to its normal grounded contact, completes a circuit from grounded contact 50, contnct 21-20 and" alternate contact 11, cut-olfirelay 12to battery B, energizing the saidgelay 12 which, by the operation of itsar'niature 13, completes a locking circ, "t for'its'elf to the same ground at content While armature Armatures 49 and 14 completes a circuit from limb P through to wiper 23. Armature- 15 removes the ground from the normal contact of armature 11 of relay 9, thereby preventing a permanent locking of relay 12 which would other- Wise occur when 'a, connector engaged contact'6 of the line. Armature 16in its-operation, opens the normal connection of battery 7 B to limb S and completes the circuit of said line limb through to wiper 25, While armature 17 opens the previously extending series circuit through relays 9 and 18, cansing the denergization of both of them and the retraction of'their armatures, that of ,relay 18 again grounding group contact 26.

Since ground at armature 50 of relay 48 is now connected to the private contact 20 individual to the line, its multiples are nonselectable by any other line selector.

The secondary off-normal switch S.O.Sw contacts 4445 were shifted at the first energization of the secondary magnet SM, spring 45 interrupting the original energizing circuit for relay 48; while spring 44 interrupts a neutralizing circuit including resistance 36 hereafter described, and said spring 45, by engaging its alternate contact, operatively associates relay 48 with the normal contact of release switchspring 46 for use in the restoration of the line selector, as

hereafter described.

It will be observed that upon the retrac tion of the armature of relay 37, which in its attracted position originally completed the neutralizing circuit for rela 28, a new path for continuing such neutra ization had been completed by the shifting of switch spring 46 occurringon the first actuation of primary magnet PM, the new neutralizing circuit extending from the ground of said switch spring 46, its alternate contact, no'rmal contact of switch spring 44, and re-' sistance 36. This circuit is of course broken on the first energization of secondary magnet SM by tlie shifting of spring 44, but before that occurred, a thirdicircuit was completed from ground at switch spring 46,

I ing of'relay 28. Thus, it will be observed thiiylikglay windings continuing until selecits alternate contact, attracted armature 51 of relay 48 and resistance 36. This last circuit "continued until the deenergization of relay 48, when the circuit of resistance 36 in the right-hand winding of relay 28 is opened at contact 51; but simultaneously with the opening of this circuit, relay 12 was operated and relay 9 denergized', the retraction of the lower armature of the latter opening the circuit through the left-hand wind that from tl1e'ti1ne',tl1e line selector starts, armature of relay 28 willremain retracted as far as line A and sw itch D are concerned, first because of the neutralized condition of tion "of the line, and thereafter because of the} practicallysimultaneous opening of the neutralizing circuits of its windings. Thus an untoward attraction. of its armature is prevented which, should it occur or exist after wipers 30 and 34 have reached contacts 3l35 of an idle line selector, would cause the initial operation of saidselector to no avail, as there would be no calling line for it to make connection with.

The relation of the master-switch to the line selectors and the calling lines which it serves, is such that as many line selectors will be started to seek out calling lines as therefore, the armature of relay 28 will continue attracted, and as soon as the wipers 30 and 34 reach contacts 31 and 35 of the next idle line selector, this switch will also be in circuitwith the right-hand winding of started; there will. then be two windings 86 relay 28, but there being three windings in circuit with the left-hand winding, its armature will continue attracted, and when wipers 30 and 34 reach the third idle line selector, this one will also be started in search of the third line. As soon as this switch starts, however, a third winding 36 will be included in circuit with. the righthand winding of relay 28. The three windings 36 will effectively neutralize the three windings 19, the armature of relay 28 will be retracted, and when wipers 3034 engage contacts of a fourth idle line selector, this switch will not be started.

One of the rarely occurring. instances above referred to where more than the required number of line selectors will be started may be imagined as follows: Suppose that the positions of wipers 30 and 34 of the master-switch are such that. the first and second steps will cause them to engage contacts of idle line selectors. Let it be also supposed that a call comes in from a line whose individual contacts are the 9th contact sets of the fifth rows in the line selector banks, and that a call simultaneously comes in from a line whose individual contacts are located in the seventh group or row of cont'acts. In such cases, a line selector D'would start, Its starting would throw wipers 30-34 upon the contacts of the next line selector; relay 28 continuing energized owing to the inclusion of two windings 19, one

for each calling line, would cause this second fit) line selector to instantly start, and the two ine electors would be simultancously perthe first one reached the ninth contacts of.

the said group, and as a result, the wipers of the second line selector would begin wiping along the fifth row in Search of the line contacts of the calling line. But the first line selector beingtwo steps in advance would reach the contacts'of the calling line first and render them unselectable so that the second line selector would continue,

passing the said contacts to be released when it reached the end of the group by means of the switch spring 43, so arranged in the switch mechanism as to be shift-ed when the line selector is over-run on its secondary movement. In' the meantime, wipers 30-34 have been ,moved to. engage the contacts of the third line selecton' This line selector has not been started since the armature of relay 28 was retracted. As soon however, as the second line'selector is released, its winding 36 is removed from circuit of relay 28 and winding 19of the sec ond calling line is therefore again effective to attract the armature of relay 28 and causes the operation of the third line selector, which proceeds in its orderly operation to select the second calling line; We thus have three line selectors operating to connect lirst selectors with the two. calling lines. Taking into consideration the various taci: tors necessary for the occurrence of the above described OpBlatl0I1,1i3 1s apparent that even in the case of callssimultaneously coming in from a single group ofone hundred lines to its master-switch; the above' operation will very rarely occur.

The amount of time required for the operation of the line selector to connect'with the calling line is exceedingly small relquin .ing, (as will be more fully understood, when the mechanical features of the switches are described hereinafter) a maximum thirty step-l') v-step movements underthe most-untavorable condition, the switch'eisb'cing of such cliaractcr that tl'iis-ninnber of steps can be performed in less than one second of time.

Subscriber A desiring his to be connected with the line 3456, iiow ttperates C2lll-' ing device to transmit. three impulses of currcnt, by rotating the said. device cloclcwise until three of its insulated teeth have passed below spring 3 and then releasing it Where on its associated spring turns the dial in the opposite direction, the three insulated teeth each causing spring 3 to engage and disengage its contact once. With the return of the dial to norma its insulated tooth at the extreme left causes sp,ing. 2 to engage its associated contact a single time, thereb sending one impulse of current over limb 'but not until the last tooth at the right has sent the last impulse over limb P.

While the-dial is at any other than at.

normal. position, the pin shown thereon is 1 brought toisuch position that tension is removed from spring 4.- which then disengages its associated contact temporarily conductively disuniting the two line limbs P and S at that point in order that impulses may be sent over the line limbs separately. The operation of the dial as described, sends three impulses of current from ground at the substation through spring 3 and its contact, over. limb P of the line, through itttracted armature 14, contact 2223, ar-

mature 49, contact 54 at switch E, upper armature of relay 73, contact 55, through the winding of primary relay PR to battery causing theenergizations and deenergizations of said relay whose thrice attracted armature, causes three impulses to flow from ground through armature spring 57, and its alternate-contact, contact 58, primary magnet PM ,-.to battery. The three resulting energizatilons of PM move the first selector switch Wipers 59-60-61 to positions'adjacent to the third group of second selector contacts, terminals of second selectors belonging to the third thousand lines including those from 3,000., to 3,999. With the first primarymovement of the wipers, the primary off-normal switch P.O.Sw contact, and the release switch RS'w contact, are

shifted to their alternate positions preparatory to the energizationof the secondary magnet SM'. 4

lV'th the return of the dial to normal,- an impulse flows irom ground at. thersubstw tion through 3 ring,2 and its contact over limb S of the ine, through attracted arn ature 1.6, contact .24-25', contact 52, through contact 62 at switch E, lower armatureiof relay 7 3, contact-64, winding of secondary relay-SR, to battery, causing the attraction and release of said relays armature and. a flow of cflrrent-from ground through spring 65 and its alternate contact, contact 66 and busy relay BR, to battery. Contacts 6770 are attracted to disconnect wipers 6061- from battery while wiping over. contacts of busy second selectors; armature 68 is at treated to close circuit from ground through the primary oil-normal switch P.O.Sw', the alternate contact of the release switch R310, alternate contact 68, secondary magnet SM to batteryv The secondary magnet having a vibratory circuit, attracts and releases its armature, the operation beingeffective to move wipers 59 .606l into engagement with contacts 868788 of the first second selector of the group. With the first secondary movement of the wi ers, the secondary ofi' -nor1 a1 switch .O.Sw contacts 58-66 are shr ted to dperatively disconnect the windings of the primary magnet PM and of the busy rela'y BR from switch springs 57 and 65, respectively. It, the second selector mentioned is idle, it will be in the condition shown in Fig. 1. Contact 86 being on open circuit, busy relay BR becomes denergized, armature 68 opens the circuit of magnet SM, and the wipers rest in engagement with the contacts of the first second selector; armature 67-70 by their retraction render the said second selector re sponsive to current to be transmitted by.

relays PR and SR.

Armature 68 in engaging its normal contact, places direct ground through the primary oft-normal switch 1 .0.8112 and release switch contacts, normal contact 68, right-hand armature ofRM and wiper 59/ upon contact 86 of the second selector and its multiples to render the said second se- K .lector busy. 3 0

It will therefore, result, that should the wipers of another first" selector now be brought to engage multiples of contacts 8687-88 of the'first second selector switch F, busy relay,BR of this other first selector then energized will have its circuitv continued in ,this condition by current flowing from grounded 'contact- 86 .to its multiple engaged, the right armature contact of RM, through attracted armature 69, of its busy relay BR, through said relay. to 'battery. The relay wi'l therefore, continue as be energized. Secondary magnet SM by the retraction of its armature will have its circuit closed and become energized and deenergized a secondtime, movingthe wipers 59,60 61 to engage the contacts of the second second selector of the grouo. If this be in use,'another lockin circuit fdr busy relay BR will be est'ablis ed'as the preceding one is broken; SM advances.thejvipers a third step, and soon until contacts of an idle second selector are reached, when owing to the insulated-condition of its contact 86, the deenergizing of BB ensues, preventing further operation of 'SM, and the wipers come tcr 'res t.

Returning to the connection being established, subscriber A'now operates dial 1 to transmit four, impulses of current through relay PR'UVQ-l the above traced path, which said relay is operated four times transmitting four current impulses from ground through alternate contact 57, normal con tact 67, contacts .60-87, normal contact 89,-

normul contact 91, primary magzet PM to battery, causing fou:- energizations of the said primary magnet. The said magnet thereby moves wipers 9f?!.l l---95' of the second selector adjacent to a group of contacts,

terminals of connectors belonging to the fourth one hundred'group of subscribers lines of the third thousand, 'this including lines from 3,400 to 3,499. With the first movement of the wipers, the primary olinorinal switch springs P.O.Sw are shifted to their alternate positions and also the spring of the release switch RS40 VVi'th the return of the dial to normal, a single impulse flows from ground at the substation through relay SR over the before traced path, said relay being 'energized and .deenergized to transmit a current impulse from ground through spring 65 and its alternate contact, through normal contact 70, contact 6l88, contact 90, busy relay BR to'battery, energizing the said relay. Its upper. armature 'and armature 98 place wipers 94: and ,95 on open circuit, while armature 96 completes circuit from ground atthe primary off-normal switch P.().Sw='

through the alternate release switch RS'w contact, attracted armature 96 and the winding of the secondary magnet 3M to battery, causing the' energization of said magnet which is eitective to cause wipers esoires to engage contacts 99-100- 101 of the first connector of the selected group.

If contact 99 belongs to an idle connector, 1t

will be on open circuit as shown at Gun Fig 1. No locking circuit for relay BB will result from the attraction of armature 97,

back, the upper armature and" armature 98, ope-ratiyely connecting the tircuits of the connector with relays Plit'and SR, rendering the connec or controllable from substation A, While armature 96 opens the circuit and the armature of said relay fallsof secondary magnet SM leaving the wipers in engageh'ient with the terminals of the first connector of the group, and, by the engagement of its alternate contact, said arm ature 96 places dead ground from the primary ottnormal switch springs, alternate contact of release switch 'RSw normal contact '96, normal contact of the right armature of release magnet RM contact 93.--99 upon the multiples of the said con}; tact 99 appearing at the other second s.e lector banks, so that if another second-so lector F. has its wiper 93 brought to engagement with a multiple of contact 99, its relay BB will be locked by current from grounded contact 99'viaalternate contact 97; secondary magnet SM then advances the wipers to engage contacts. terminals of the If this consecond connector of the group. I tact 99 belongs to an idle connector, the second selector will stop its secondary movement and the contact 99 will be rendered busy as described in connection with the second selector I so that a third s cond -j 5 adjustment they are lector seeking a. connector in the same group willselect the third connector of a group, and so on.

With the first secondary movement of the wipers 93, 94, 95 springs, 89-90 of the secondary off-normal switch ed to opcratively disconnect primary magnet PM and busy relay BB from relays PR and SR. Subscriber A now operates dial .1-0 1 transmitting five impulses ofcurrent from ground at the substation through relay PR, causing. five actuations thereof, which are effective to transmit five impulses of current I from ground contacts 67, 60-87, 94-400, normal contact 102, contact 103, through primary magnet PM at the connector G to battery. Five resulting actuations of said magnet are effective to move Wipers 105'106-107to positions adjacent to a group of ten contacfisets in .their banks, forming terminals of the fifth group of the one hundred lines which the connector serves, namely: terminals of lines from to 3459 inclusive, followed by terminals-of line 3450, it being understood that zero is represented by ten current impulses. With the first primary movement of the wipers, primary off-normal switch spring 110-Sin is shifted to operatively connect contact 99, via-normal contact 122, with the winding of ,the release magnet RM to place the same under control of the calling subscriber, as will be hereinafter more fully'explained.

With the return of dial 1 -to normal, at single impulse is transmitted after the last of the five preceding ones fr'om ground over limb S through relay SR, traversing a-be fore traced path, actuatin relaySR a single time, whose armature is efi'ective to transmit a single current impulse as follows: from ground, contacts 65, 70, 61, S8, 98, 95, 101, normal contact 108, 'net RM through secondary magnet to battery. The secondary magnet SlVP is (5 thereby actuated a single time moving wipers 105, 106, 107. one step nearer the selected contact group, it being understood that the normal positions of the wipers of a connector are such that after any primary two steps distant from the first contacts of the group selected. lVith the first secondary movement of the w-i ers, springs 102]08 of the secondary 0 normal switch 3.0.820" are shifted; 102, 'to enjilage its alternate contact, while 108 is shiftedtonly sufiiciently to disengage its normal contact; a second step of the wipers being required to shift it sufliciently to on gage its alternate contact. This arrangement of spring 108 is for the following pur hose: to prevent an otherwise possible premature operation of test relay Tlt WlUCll would occur were spring 108 completely shifted to engage its alternate contact before secondary relay SR had its armature resir,

$11810 are shift-' sequent wipers 106107 which through alternate contact 57,

spring 57,

lower armature of magthe impulse transmitted by tracted; grounded alternate SR through contact 108, lower armature ofrelay 109, left-hand Winding of relay TR to 1 battery, which wouldcause the energiZation and deiinergization of relay TR and the con f 111 of the test switch. would cause ringing gized to include generator in circuit with: should properly be; on open circuit during the other seconeiiary movements to connect with the called line. Subscriber A now operates dial 1 to transmit six current impulses from ground at the substation through primary relay PR, causing six actuations thereof and six current impulses to be transmitted from ground via over the before traced path, con tact 102, the impulses then passing via alternate contact 102, normal switch contact of. upper armature of relay l09,'lower armature of magnet RM secondary magnet SM to The first resulting actuation of secondary magnet SM moves wipers 105- 10('3 107, now on their normal open circuits, to engage contacts 6, 7-and 8 of the first line of the group, or line 3451, and with this movement, the complete shifting of secondary off-normal switch spring 108 is accomphshed; The succeeding five actuati'bns of 8M are effective only to move wipers 105- 106107 successive steps, the sixth actua tion causing them to engage contacts 67+ 8, multiple terminals of the called line 3456 belonging to subscriber B. After the trans mission of the last of the six impulses, a single inipulse is, in the usual manner, caused to flow from ground at the substation over limb Slto secondary relay SR Whose actuation transmits an impulse from ground through contact 65 over the before traced path to contact108', thence via its alternate contact and the normal contact of the lower 1 armature a relay 109 through the left-hand.

winding of test relay TR, to battery, causing the said relay to attract its, armatures. Let it be first assumed that the called line B isidle, in which case as shown, contact 6 is connected to battery B through the winding of cut otl relay 12, there being no ground connection to the said contact except through battery; The attraction of the right-hand armature of test relay TR connected its right-hand winding from battery through said attracted armature, normal contact 10%, normal contact 110, wiper 105, to contact 6, but since this contact is already connected to battery, upon the cessation of secondary relay shifting of switch springs 110 and 5 The shifting of 111 relay 112 to be ener- SR, test rclay'TR is detinergized, its armatures falling back, this being effected to shift springs 110 and 111 of the test switch Ta m. The shifting of spring 110 connects groulnl to wiper 105, contact 0 and itsmultiples, completing circuit through cut-off "relay 12 of called line B to battery. The resulting attraction of armatures 14 and 16 v +6ompletes the circuit over limbs P and S of the called-for line to contacts 7'and 8. That of 14 also disconnects line relay 9 from limb 1 The shifting of test swltch spring 20 111, completes circuit through relay 109 from ground, spring 111, contact 115, ringingrelay 112, to battery B traction of the armatures of relay 109, a circuit is completed from ground through nor- 2 mal contact of the lower armature of relay 1%7, normal contact 119, attracted armature o relay 109, alternate contact 102, cont-acts 10094, 87-60, contact 67, normal contact 57, contact 71, magnet 73 to battery, causing the energization of said magnet 7 3 whose attracted armatures complete a bridge of battery B in'the line of subscriber A from ground through upper windings of relays 74: and 75, attracted upper armature of relay 5 73, contact 54i,'to the left over the heavily marked conductor, to limb P through the ltransmitter at the substation, returning over llimb S and the other heavily marked coni :ductor, contact 62, attracted lower armature 49 bf relay 73, lower windings of relays 75 and 7 1 to battery. Differentially connected rel ay 7 1 ,is not energized, the flow in'its two windings being equal but cumulatively connected relay 75 attracts its a-rmatures of which 56 and 63 complete parallel paths from ground and battery to limbs P and S respectively, while contacts and 64; disconnect relays PR and SR- from the talking circuit. 3

Having explained the effect of the shifting of spring 111 at G with respect to the first selector, I will now describe its effect with respect to the called line. Its shifting energizesringing relay 112 over a before traced 55 circuit and the attracted armatures of said relay cause alternating current to flow from generator G upper armature of relay 1'12, contact 1067, alternate contact 14, limb P of the line of B, normal hook switch contact,

bell and condenser, limb S, alternate contact 16, contact 18, 107, attracted lower armature of relay, 112, lower winding of relay 113 through \battery B The interrupter I is W provided in the circuit of generator G? so arranged {as to periodically connect the said line, in the well-known manner.

On the resulting at-fl generator in and out of circuit; ith said it will be observed however, that the brushes of I are so arranged that at all times during the ringing, ground is connected to limb P of the rung line either through generator or the grounded brush of the interrupter. Y

It should be observed that the character of relay 113 is such that the flow of generator current through the substation condenser does not actuate the relay. As soon, how ever, as the called subscriber answers the call by" removing his receiver, the substation hook lever engages its alternate contact completing a conductively continuous circuit from ground through generator G or interrupter 1 as the case may be, to limb P over the before traced path for ringing current, the alternate contact of the hook lever and. through the transmitter, returning over the limblS and thence overthe before traced path and the lower winding of relay 113 to battery 13". Current flowing over this conductive circuit, energizes relay 113 whose attracted armature 114: first completes, by engaging spring 115, a locking circ'uit'including serially the already energized relay 109 and the upper winding of relay 113 causing 'bot-h relays to remain energized, the said armature. immediately thereafter breaking the normal contact 115, thereby efii'ecting the dee'nerization of ringing relay 112 and the immediate exclusion of generator G from connection with the called line. The attraction of the lower armature and armature 116 of relay 113 bridges relay 117 across the called-for line, which relay is immediately energized by current flowing over said line. The lower armature of relay 117 disengages its normal contact whereby the before traced circuit through magnet 73 at E is interrupted and the said magnet is deenergized, the consequent retraction of its armature shifting springs 5%71 and 62-72 to their alternate positions. The deenergization of 73 does not effect the continued energization after breaking the normal contacts of said springs reverses the connections of battery B to the calling line, causing a reverse flow of current thereover through the substation. This reversal of direct current over the calling line occurrin when the called subscriber answers the call, may profitably be employed for various purposcs,.as for instance, in connection with the polarized structure shown in Fig. 5 of my United States Letters Patent. #830 ,('53, issued September 11, 1906. The attraction of armature. T7 encrgizes printing magnet 77 which thereupon by the aid of its associated mechanism prints the nulnber of the calling line recording a completed call against it.

Returning now to relay llT at. (l. having explained the et'l'ect ot the lower armature. of said relay in disengaging its normal contact, it will be observed that the said armature engaging its alternate contact, completes a. circuit from ground through relay 118, said relay 118 by the attraction of armature 121. establishing a locking circuit for itself through switch spring 110 ol' the test switch-'lhw to ground. Armature 11$) com pletes the talking circuit to wiper 106; armature 120, closes a break in the circuit of release magnet RM", while armature 122 in leaving its normal contact removes the previously existing control of release magnet RM from the calling substation, and by engaging its alternate contact. places an ilulependcnt groundupon contact 99 and its multiples, so that the connector is now rendered unselectable by any other second selector until both subscribers have replaced their receivers, which will be hereafter more fully explained. The two subscribers A and B are now in conversation. circuit being traced from substation A to substation It by m *ans ot the hca vily marked conductors and condensers 81-82 through the exchange, talking battery being supplied to the calling line through the impedances of relays 74--75 and to the called line through the impedances of relay 17 at the connector.

Vhen the subscribers have finished their conversation, they replace their receivers upon the hook levers. the act of subscriber l in so doing restores the connector (i to normal. while the act ot subscriber in so doing. restores line selector 1 tirst selector ti and second selector F to normal. The purpose of dividing the control o't-the release in this manner may be stated as tollows: lrimarily. it is o'l course dc:-:irable that each subscriber b able to tree his line from any switch connected to it lest. should one subscriber have sole control of the re lease. he might by carelessly or maliciously failing to hang up his receiver, hold the other line busy preventing its use. The control of the release of the connector by the calling subscriber, after the called sulr scriber has answered. is preferably pre vented because were it allowed, when the calling subscriber replaced his receiver first thereby causing wipers 1(l5 l06- -107 of connector (1 to leave contacts ('-7 -8 of the called line,,it would result that upon the to cause the release at the 'lhe replacing of the opening circuit through breaking of contact 105(, outwit relay 12 of the called line would be det nergized and upon the retraction of its armatures, the substation receiver at B being otf the hook, relay 9 of the called line would be energized causing the selection of the line by one of the associated line selectors. The called subscriber B, would of course be replacing his receiver at about this time, and if he replaced it before the line selector co1'n] )letcd the selection, the said selector would come to rest in connection with the line, and so remain rendering the line busy against incoming calls, etc.

\l'ere the called subscriber enabled, 7 replacing the receiver, to restore all of the switches used in the connection including the line selector connected to the calling line. the inconvenience. pointed out in the preceding mragraph would be duplicated.

In consequence ot the division of the release operations indicated, the armature 122 and its grounded alternate contact is provided which etiective as subscriber answers, to place a second ground upon contact 99 ot' the connector 'and its multiples, in addition to-the ground already placed upon said contacts by the operation of the second selector lest, should the calling subscrili er release the second selector (thereby opening contact 99-93 before the calledfor subscriber B replaces his receiver), another line selector F in connection with another calling line. seeking an idle connector in the same group. might select the connector already. connected to called line B. It will he thus seen that although subscriber B has independent control. of the restoration of switch and sn'bscriberA has independent control of the release of the other switches, D. E and F,' the cooperation of both is required to remove the busy potential from the private contact 99 ot' the connector.

I will now trace in detail the release operation occurring when the subscribers replace their receivers. Vl'hcn subscriber B does so. the operation oi arm 5 of the hook lever upon its associated contact springs, momentarily grounds limbs l and 5' in the usual manner. but this operation is not used called substation. receiver causes the its alternate contact relay 117. held energized by current over the line during eonversation. The upper armature of relay 117 then falls back. and completes a circuit through release magnet RM from ground through contact. 120 of relay 11S, upper armature contact 01 relay 117 to battery. (it-- fecting the encrgization ot' the release magnet whose arlnature is thus attracted. shifts the switch springs 110111tonormalfopei'iing the circuit of relays 109, 113 and 11% causing their denergizations. The deenerbook lever to disengage soon as a called. I

gization of relay 11S opened the circuit of the release magnet RM whose armature thereupon is retracted and wipers l05106- 107 allowed to return to normal, their restoration causing, on its completion, the shifting to normal of the primary oft-normal switch 1 .0.310 the secondary oil-normal switch springs SOS m being restored at the time the wipers'have been restored as to their secondary movements. When the calling subscriber replaces his receiver, arm 5 temporarily grounds limbs P and S of the line, the grounding of limb S short-circuit ing the upper winding of differential release relay 74, and, current continuing through the lower winding of said relay to ground at the substation, its armatureis attracted to complete circuit through release magnet RM at switch D; from ground, at tracted armature ofrelay T l, release magnet RM of switch, E to battery. The attracted right-hand armature of release magnet RM closes circuit through release mag net RM at second selector' E from ground through the shifted primary oft normal switch P.O.Swcontact, contact 86 59, at tracted armature of RM to battery. 'lfhe release magnets of all the switches D, E and F, are now energized and their energizations shift to normal the various release switches RSw, RSw and RS10 the shifting of said switches causing respectively the energizations of relays 48, BR and whereby the Wipers of the various switches are dis connected from battery and so held during the release of the switches. In the restoration of the hook lever at substation A, arm '5 passing from the top of its associated contact spring, removes ground from the two limbs of the line and the armature of relay 74 returns to normal deenergizing release magnets 11M and RM, the deenergization of RM opening thecircuit of RM The denergizations of the various release magnets RM, RM and Ell I cause the restoration of the wipers of the various switches with which they are associated. When. the switches have. reached normal as to their secondary movements, the secoudarr ofilnormal' switches SOS-w, SOS w and S.().Sw are restored; when the wipers have been restored as to their. primary movements,

tacts (3, 7 and 8 of the called line, this line was a busy line. in such case, groundovill be connected to contact 6 and its multiples via the shifted test switch TSw, contact 110 of another connector (it the busy line be a 0 called line), or via armature 13 pertaining to the busy line, its contact 20, wiper 21 of a line selector then connected thereto, to ground through contact 50 at the said line selector (if the busy line he a calling line). 75

In either case, upon the energization of the test relay .Tlt at switch Gr, as before described, the said relay, instead of being thereon deenergized, will have its armatures locked in their attracted positions by cur- 8Q rent from grounded contact 6, wiper 105, normal contact 110, contact 104, right armature of relay TR, its right winding to battery. The testswitch contacts therefore remain at normal. and a busy signal is transmitted to the calling subscriber from interrupter I through the induction coil and condenser, left armature of relay TR, normal contact of lower armature of relay 109, to

the left over the talking circuit indicated hy'90 heavy lines to switch E, via normal contact 70, condenser 83, to the left over the heavily marked talking conductor, limb S of the line of A, through the transmitter and the primary of the induction coil, causing an audible signal in thereceiver, returning over limh P, to the right overthe upper are still operatively connected to line limbs P and S rcspectivelyand they are therefore, on the grounding of the line limbs, both simultaneously energized to close contact 84t-85. Circuit is then completed from ground at release magnetv'ltM of the line,

selector, contact 85,84, release magnet RM of the first selector to battery. RM attracts its armature, closing circuit from ground at release uiagnet BM of second selector. F, through alternate contact of primary oil-normal switch 1.O.S'w contact 8(359, attracted armature of RM- to battery. The attracted armature of RM closes circuit from ground through RM at the connector, normal. contact 122, the

shifted contact of primary off-normal switch ROS e0 contact Shh-93, attracted armature of RM to battery. I The armatures of all the release magnets are now attracted; and

when'gro'und is removed from) the two line "limbs at substation A, the resulting de'e'nergization of relays PR and SR allows contact 885 to be opened, deinerg'izing RM and Bhlflthe deenergiaation the latter detinergizing Eli i the dctinergization of The calling sub- 100 RM deenergizing HM; and each switch' is restored as its release magnet RM, RM, etc., isdeenergized. Thus it. is seen that until the called subscriber answers the call, the release of the connector remains under the control of the calling subscriber; the instrumentality controlled by the called subscribcr for removing the calling subscriber's control of RM, consists of 122 of relay 118, which, when actuated, by disengaging its normal contact, opens a contact. in the circuit of RM and thereafter puts the. second busy )otential upon contact 99, as before described.

From the release operations already described, it is apparent that as soon as the line selector has selected his line, the calling subscriber may, by grounding. the two line limbs simultaneously, cause the closure of contact 85-84, which will be effective to release whatever switches are connected to his line, so that, whatever stage of completing a connection may have been reached, the release of all switches so far 0 erated may be secured.

As before indicated, it may sometimes happen that a line selector will over-run on its primary or secondary movement through accident or certain rarely occurring combinations of circumstances. To take care of these occurrences, I have provided the two switch springs 43 and 53; the former being so related to the switch mechanism that, if the switch shall make an eleventh primary movement, the contact 43 will be closed; while if the switch makes an eleventh step in its secondary movement, the contact of 53 will be closed. In either case, a circuit will-be completed from ground through the release magnet RM, contact 43 or 53, as the case may be alternate contact 47 of the rclease switch ES w to batter energizing relcasemagno RM, upon whose energization the release switch RSw will be shifted to normal, spring 47 then opening the circuit of release magnet RM, whose. deeucrgization causes the restoration of the line selector.

Referrin to armatures TSand 80 oil" switch E controlled by relay 76: their func- .tion to take care of certain dillicult ics which might occur were they omitted, being as follows: Assuming that the called subscriber has answered the call, causing the cnergiza- 'tion '01 relay 76, then it will be remembered that current flows from ground at I). up per windings o'l relays Tat--75. attracted armature 50. attracted armatlu'c 79, o\cr the talking circuit to limb $4. returning ovcr limb l.atlractcd armalurcs To and (12}. to battery through the lower windings ot relays T5 and 7-1. It is thus seen that the cir-- cuit energizing relay T i i.- t|'accd through its own armaturcs 54' and (113 and the calling line. Assuming that during conversation the calling subscriber accidentally moves armature spring his dial Z from normal. the resulting opening of his linecircuit'. a t. contact. 4 would deenergize relay 7;"); its ari'mltnrcs 5t) and (311 would tall back; and when the line at A wasagain closed condnctively, relay T5 wound continue deiinergized so that when the subscriber replaced his receiver, ditt'ercntial release relay 74 would be out of openativ'c relation with his line. .-\rmature con-- tactsih and 80 are therefore. provided. controller l by relay Tti (which is only dciinergized when the release of the first. sclectoi actually occurs) establishing, when attracted, a parallel path for current through the windings ot relays 74 and 75, thearmatures 56 and 63 being excludedfrom this circuit so that an accidental opening of the line circuit at the substation of the calling subscriber, causing temporarily the denergization of relay 75,v does not put the central oflice apparatusin such condition as to prevent the said relay 75 from becoming again energized when the substation circuit is again closed.

Referring now to the mechanical drawi ngs, as shown in Fig. a preferred form of the master-switch, the contacts 31 and 35 are the terminals of the line selectors, while the contacts 30 and 34 extend around under the respective rows of contacts 31 and 35 the wipers 30" and 34- (Figs. 2 and 3) having in themselves no circuit connections, be"- ing employed only to successively cross the individual contacts 31. and 3:") to the respective' common contacts 30 and 34-, leading (as shown in Fig. 1) to the armatures of ,relays 29 and to relays 32. The said wipers 30 and 34 are fastened 30 adapted to be driven, stcp-by-step, by thearmatiure-actuated pawl 30 of magnet 33, the magnet: being provided with an interrupter actuated by its armaturi. as shown.

A line selector (Figs. +l, 7, 8 toll inclusive), comprises essentially ten group con tacts 26 and a group wiper 27, making primary movementsonly, a contact bank including one hundred sets of contacts 22, '20, 24, arranged in ten groups of ten sets of contacts each, a set of wipers 23, 25, 21, capable of primary movements to select a group and secondary movements in an intersecting plane to select ,a contact set of a groupQa. primarv otl'-normal switch ROS)! comprising switch springs shifted on the first primary movement of the wipers, a secondary oft-normal switch $0.82!) comprising switch springs shifted on the first secondary movement of the wipers, a release switch H.910 comprising springs shitted on the first primary movement of thcwipcrs, a prin'iary over-run switch shifted when primary movement takes place and a secondary over-run switch shifted when a'ncleventh secondary movement takes place. i

A sectional view of a. bank seen, from the to a rotatable ratchet an eleventl'i- 144 whose momentum is ell'ective, on the atbe caught and held bv the hook of arm 13']. hen magnet RM is now dciincnqizcd, its retracted armature draws arm i230 to the right, which. keeping its hold on delcnls l 125 and 12%. moves them away trom their shaft ratchcls so that; the shafts are.now free to be restored. shaft SS by spring 231 fastened to the wipers. and shaft PS by spring 161.

A spline .170 (Figs. l and 9) ishprovidcd on the secondary shaft engaging with tha first movementthereof any adjacent tooth ot ratchet 124 to hold the primar sha'l't against return movmnent. to the end that on I the restoration of the shafts as descrilicdf the secondary shaft may be first completely restored clearing the wipers from thebank, whereon spline 170 releases the primary shaft and permits its restoration. 'lhe'ivri} mary and secondary cit-normal switches arc.- of course restored by the. respective. shafts" when they reach normal. the restoration of the secondary one occurring first.

Recapitnlating the principal operations: the first actuation of primary magnet PM rotates the wipers a step. shifts the primary elf-normal switch. releases the primary and secondary shal'tdetents and shifts the re-" lease switch. Subsequent actuations of said magnet serve only to advance the wipers successive primary steps, until a possible. eleventh step when the over-run switch is shifted. The first actuation of secondary magnet SM advances the line wipers a ondary step. shifts the secondary oil-normal switch. and interlocks spline 170 with ratchet 124. Additional actuations of said magnet merely ad once. the line wipers additional secondary steps until a possible eleventh step when the secondary over-run switch will be, shifted. The'relcase magnet when energized shifts the release switch to normal, and when detinergizcd withdraws the shaft detents, restoring the switch.

The mechanism associated with magnet '77 of Fig. 1, part .1. is shown in detail in the top view (Fig. 15). It includes the suitably pivoted teed-spool 14-5 carrying a supply of Inked ribbon 153-and record ribbon 152 which may be of paper in alternate laytu s, and the receiving-spool 140 to which lastcned ratchetv ll]. operated, to wind the ribbons oll'thc teed-spool onto the rcccivingspool, by the pawl H52- l'astened to arm lfit) upon armature 1 13, the attraction of said armature serving to draw pawl it.) to the left to engage the next tooth of ratch t 141. so that, on the retraction ol the. arn'iaturc, pawl 142 rotates ratchct 1 l] and spool Ht) a. step. .-\r1nature 143 carries a hammer piece traction of t lt), to give a reboundingblow upon the portions ot ribbons 153 and 152 that :n'e'adjzu-entv to the hannner, prmtmg upon record ribljioi'i 155! whatever number upon the curved type trame o eration of the line elector, have been brought opposite the hammer 1'l-l-. The gene .l conformation of type frame 146 and its association with the primary and secomlary'shatts will be seen in Fig. 15 and Figs. ll. ll) and 11. The cylindrical bearing ol. .t'ranu: 'l-lti is splined to primary shaft PS (a shown in Fig. 1:1) so that. it is rotated with lhesha'tt, but is tree to move down and up thereon. The lower edge of the frame Ill; is pressed agail'ist a projection .1119 on secondary shaft SS (Fig. spring 11-? shown in Figs. 1), l0, and 11. to the end that. when shaft SS is worked downwardly in the operation of the line so. lcctor, spring H9 may move. the type frame 1 H] a corresponding cxlent downward.

The type numbers corresponding to the respective tens and units values ol the subscribers lines in their respective hundreds arc to secure greater spacing, preferably arranged in ten vertically disposed double col-- nmns. as indicated in .l igs. 10 and ll, numbers 11, 12. 13. H. etc, comprising a double column.

sllll]il1; that subscriber 9924. makes a. call. the primary shaft. ll'i of the line solector Fig. t. makes of comr'se two rotary steps which bring the column of numbers including g1, 22, 23. etc, to a position directly above the hammer end 151, (Fig. 15). The. secondary shaft HQ then makes four downward steps to bringthe wipers to connectv with the contacts ol the line, and spring 1 17 causes the type -l'rame to descend correspondingly. number Z-l being thereby brought di rectly opposite the cnd 151 of hammer .144. Similarly, it" any other subscriber makes a call, the line selector o 'ierating will, with the zuljustment of its wipers. move its type frame so that the type number correspond ing to the number of the. calling line 1s adjusted to the hammer. \Vhen a'line selector is restored its shafts of course restore the type frame to normal.

'lelcphone subscribers on measured service are usually'cl'iargod only for such calls as are answered, and to conform to this practice. l have so arranged the circuits of my svstcm that printing magnet 77 is only operalcd in case aml at. the moment when the called subscriber responds. .\t that time it will of course record the number of the calling subscriber on ribbon 152. hen the 146 may, by the calling subscriber at. the end oi".conversationcauscs the first selector to be restored, mag-.

net 77 is detincrgized and pawl 142, turning spool 14-0, ln'ings fresh spaces of ribbon in front of hannner and 151 ready to print; the next number. Since, the line selectors belong to a particular one hundred lines, it is necessary, in order to get a pernianent printed record of each completed call over a line, to place upon the type frames of the ten line 1:3) by a spiral selectors only the last two digits of each subscribers number, the line selector itself indicating the thousands and hundreds digit.

It is apparent that only one thousand call recorders are required tor ten thousand subscribers lines, a material. saving' over recorders individual to lines.

The mccluinisni of the first, selector is, in general, similar to that of the line selector. The vibratory interrupter of the primary magnet and the measured service mechanism are omitted.

The primary oiT-normal, secondary oil normal and release switches are controlled in a nianner similar to'those of the line sclector, and the adjustment of the line wipers is mechanically similar, The spring combinations of the various off-normal and lease switches corrcs 'mlnl of: course to those indicated at E in i.

In Figs. 5 and (3 shown the nicchanisn'i associated with the first HElrAjlGl' for shifting Sp]; 5 7i, and Ti, 32, dime-Flinn. in (:-f)l'i nectlon with .lig. l; springs mounted as indicated in Pig. o, the vied slimving the springs at normal. The two insulated studs .135) are drawn to the left to shift the springs, and when they are freed the tension of the springs rot-ores the studs and springs. The studs 12-35 are fastened to an arm 134 (Fig. (5) pivoted as shown, and having a small projection on its lower e trcniity adapted to he engaged by the hook of arm 133 when the arn'zaturc of magnet 73 is attracted. i lhen said magnet is there; er deener ized on the response of the called subscriier, its retracted armature causes 133 to draw the lower portion oi. nie'i'nher 134 to the right, whereby studs move to the leftto shift their snrings.

The operation of release magnet RM is similar to that of magnet RM of the line selector, except that its armature carries an arm 136 adapted, when the armature at ti'acted, to en 'ag e and lift hooked arm 133 free of mem 1' 134, thus allowing the restoration of studs 135.

It will .be reinemhere'd that the shifting of spring 72 (see Fig. 1) energizes relay 76, whose energization causes-that of the printinfigmagnet 77. The latter should preferab y not be operated when a. calling snh-- scriher has connected his line with. an idle called line and fails to secure an answer. Under such circumstances, magnet 73 is ener gized as soon as connection is madc wit-h the called line, and its denergization follows when the calling subscriber replaces his 1"- ceiver, causing the energization of releas maiet RM, which, by shifting spring 1h. 24;, energised relay BR whose armatnre opens tie circuit of magnet 73. The previous encrgization of 73 has,cau sed arm 133 to engage member 1.34 (see Fig 6) The energization of magnet RM, preceding the deenergization of magnet 73, is effective lo cause arm 1.36 to lift arm 133 free that the deenergization of magnet 73 (oc curing while magnet RM remains energiZ-cd) is inetl'ective to move n'ielnher 134; spring 72 and the other associated springs remaining at normal, \i'hsri'el'iy an improper I)(J&lll )ll o'l magnet 77 is avoided.

The second selector is mechanically similar to the first selector, except that .n'iagnct 73 is not employed, the various ofi norinal and release spring con'ihinations being a1." ranged as indicated at F in Fig. 1.

The connector shown in Figs. 12, 13, 14 inclusive, is generally similar to the first selector. No vibratory circuit-breaker of the secondmy magnet SM is provided and the positions of the Wipers with respect to the contact bank is such that two secondary steps are required tocause the Wipers to engagc the first contact set of a selected rovv for the purposes hcreinhefore indicated.

'ihe niechanis ,1 of test relay TB is best shown. in Fig. 1 1-. The test switch sprin lid-ill are preferably vertically disposed and am; 1.37, carried by the arn'iatnre of relay TR, has a raised portion adapted, when the armature is attracted, to clear spring 111, the spring associated with arm then missing the upraise'to engage said spring 111. Uri the deenergization of relay TR, the springs 111i. and 210 are of course shifted for the purposes hereinhefore in? by arm 13.: dicated. When release magnet attracts its armature, piece 138 fastened thereto draws arm 13? down so that its upraise frees spring 11.1 and the twosprings 11 0, 111 by their tension return to i'iorinal. .Moreover it will he -h served that when testrelay TR is locked because the switch wipers have engaged terminals of a has} line, the energization of the release magnet. 3M (occuring when the calling subscriber replaces his receiver) will be eilfective by piece 138 to Withdraw arm 137 from engagement with sgring 111} so that the springs remain 1111-- s ifted, It is to be. u'ndestood that Fig. 1, purely symholical diagram, the various isa cated by conventional signs, no attempt hecon doctors, relays, anhatnres, etc being indiing made to indicate mechanical structures therein or particular types of apparatus, as those skilled in the art will readily supply the mechanisms best adapted for practicing the invention. Similarly, any known or approved mechanical combinations may he employed in place of the particular con'ihinations 1 have elected to illustrate in the me chanical' drawings, and I do not. intend to limit. my invention to switches having movementsin intersecting planes. The various batteries illustrated at B, B and B may, if desired, he a single battery.

It is my intention not to limit the scope

Images