US1267980A

US1267980A - Automatic telephone-exchange system.

Info

Publication number: US1267980A
Application number: US87804714A
Authority: US
Inventors: Edward B Craft; John N Reynolds
Original assignee: Western Electric Co Inc
Current assignee: AT&T Corp
Priority date: 1914-12-19
Filing date: 1914-12-19
Publication date: 1918-05-28
Anticipated expiration: 1935-05-28
Also published as: USRE15341E

Description

E. B. CRAFT & J. N. REYNOLDS. AUTOMATIC TELEPHONE EXCHANGE SYSTEM.

APPLICATION HLED DEC. t9, l9l4. 1 ,267,980. Patented May 28,1918.

3 SHEETSSHEET 1- W/fnesses: Q9741 M 4 IiSHEETSSHEET 2.

Patented May 28, 1918.

E. B. CRAFT 64 J. N. REYNOLDS.

AUTOMATIC TELEPHONE EXCHANGE'SYSTEM.

APPLICATION FILED 05c. 19. 1914.

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AUTOMATIC TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED DEC. I9, 1914 0Q 1 9 m I l 1} H m mm. 0 w f m n M w w Nah ma n e M P llll llll W/fnesses: @257?! M2 Edward 5 Crafi. John /V. Freyno/ds.

.for identifying engaged lines.

UNITED STATES PATEN T OFFICE.

EDWARD B. CRAFT, 0F HACKENSACK, NEW JERSEY, AND JOHN N. REYNOLDS, OF GREENWICH, CONNECTICUT, ASSIGNORS. BY MESNE ASSIGNMENTS, TO WESTERN ELEI TRIC COMPANY, IIUJGRPORATED. A CORPORATION OF NEW YORK.

A'UTLGMATIC TELEPHONE-EXCHANGE SYSTEM.

application filed December 13, 1914.

To all rrhmii it may Muir-cm Be it known that we, lilowaau l5. Chain and Jon n N. Rnr'nonns, citiacns of the United States, residing at. Hackensack, in the county of Bergen and State ol New Jersey, and at Greenwich. in the county oi Fairiirld and State of Connecticut. res 'aeliitively, have invented certain new and useful Inc prorenicnts in Automatic 'ielcphone Ex change Systems oi' which the billowing a. lull. clean conch-c, and exalt! description.

This iurentioxtr in anus rcspc h rrlatrs to telephone exchangr s5 stems gr.- y, but it is applicable more particularly to systems employing autonn tlr switihc for distrihi ing calls to connecting circuits of operators positions.

In one respect its object to adapt an automatic switch of a type having multiple connected brushes for use as a quick-acting line or trunk finder, and to this end the brush selecting mechanism of the switch adapted for adjustment in accordance with the group in which the terminal of a selectable line or trunk lies, and the brush carrier element is adjusted in accordance with the location of the terminal in that group.

In another respect its object is to gain time in cxtciuiling a connection to a call re cciving device. such as an operators telephone. The invention in this respect is espcrially applicable. to a call distributing systern. wherein a two-movement automatic switching mechanism operates first to find an idle operator-s position and then to find an idle connecting circuit in that position. As thus applied it provides for the connection of the operator's set to the line calling in the first switching movement.

In another respect, applicable to auto-- matic switching systems in telephone cX- changes generally, its object is to provide easily manipulated and simple mechanism To this end each line is provided with identifying: means operating over connections preferably established by the automatic switching apparatus from any operatic-s position.

In another respect, its object is to provide simple means for effecting a number of different identifications of a line. To this end, each line has associated with it means for identifying it to the tinder switch as a call ing line, and means for identifying it to the Specification of Letters Patent.

Patented May 28, 1918.

Serial No 878,647

O Tui'tll -fll as a -lartieular calling line. This is done over a path that is used for one identification at one time and for another idcntilicat ion at another time.

In another respect, applicable to systems for distributing calls to operators" positions or to systems in which lines a re connected through automatic switches in series, its ohjtt'i to enahlc the operator to render a connected line available for other connections while continuiim the connection already cstahli hcd. To this end prehirahly the. circuit ot' a cutoff relay for the line is extended lithe operator position, a lie-y heng pro ridcd for controlling;- that circuit.

'lhese and other features of this invention will he more fully considered in the following description of a call. distributing system with reference. to the attacl'ied drawings, in which- Figure 1 illustrates the calling subscrihcrs line, the line finder and the associated con t rolling apparatus;

Fig. 2 illustrates the operators position at the finder and connecting finder with their associated controlling apparatus; and

Fig. 3 illustrates the. operators listening circuit, the operators connecting circuit" and the associated controlling apparatus.

The calling subscribers station 1 of Fig. 1 is provided with the usual switch hook for closing the circuit of the line conductors 3 and 4. Vhen this circuit is closed on the initiation of a call, current. flows from hattery ojhrough relay 6 which is common to a group of lines terminating on the contact points which constitute one level in a group of line finder switches, through line relay 7, contact 8 of cntofl' relay 9, line conductor 3. switch hook 2, line conductor 4 and contact 10 of cutolf relay 9, to earth. The current in this path actuates group relay (3 and line relay T. The actuation of relay '6 closes its contain 12. thus completing a circuit from earth. through conductor 13 which is common to contact points similar to 12 on all of the group relays ti associated with the. sub scrihcrslines terminating in one group of line finder switches, through sequence switch contact 102-1 and through sequenceswitch operating magnet 100 to battery 5 and earth.

Sequence switch 100 and sequence switches 200. 300 and 400 may be similar to that illus trated in patent to F. R. McBerty, No.

1,009,080 dated November 21, 1911, or of an other suitable type.

witch 100 controls sequence switch contacts 101, et seq. Contact 101 of sequence switch 100 is arranged to close the local circuit for the sequence switch operating mag- ,net in all positions of the switch except those indicated by the figures adjacent to contact 101. This provides that the switch may stop only in the ositiops indicated. The other sequence switch contacts 102, et 'se are closed onl in the positions indicated y the figures a jacent to the respective contacts.

The current flowing through conductor 13, sequence switch contact 102 1 and the operating magnet of sequence switch 100 causes the movement of the sequence switch from its first to its second position. In this position a circuit is completed from battery 5 through clutch magnet 16 of the grou finding brush trip shaft 19 associated witi line finder switch A, contact 1032, contact 34 of relay 29, to earth. This brings the driving disk 17 into frictional engagement with the shaft disk 18 and causes the shaft 19 to rotate in a counter clockwise direction. The upper end of shaft 19 carries the brush 20 which, in its rotation, wipes over the group contact points 21. These contact points are normally disconnected from bat tery, but upon the actuation of grou relay 6, a particular one of the contact points 21, corresponding to the levclof contact points in which the calling subscribers line terminates, has battery potential connected to it through contact 22 of relay 6. When the shaft 19 is rotated to the position at which brush 20 engages contact point 21 of the level including the calling subscribers' line, a path is completed from battery 5 through the non-inductive resistance 25, contact 22 of relay 6, contact and brush 21 and 20, sequence switch contact 1042, conductor 26, winding 27 of test relay 28 and the coil of test relay 29, to ground. The current in this path actuates relay 28, closing a low resistance path through its contact 30 and winding 31, and actuates relay 29. The actuation of relay 29 severs its normal contact 34, thus interrupting the current through clutch magnet 16 and stopping the rotation of shaft 19.

Located at equal intervals along shaft 19 are brush tripping fingers 23, angulurly disosed with respect to one another, and equal in number to contact points 21. The function :of each finger 23 is to releases particular set of brushes 40, 47, 48 and 49, correspond ing to the contact level of switch A in which the calling line teminates. The degree of rotation necessary to bring the desired tripping finger 23 into operatin position is determined by the selection 0 the contact point 21 by brush 20, as described above.

To prevent the rotation of shaft19 from stopping the instant that brush 20 comes in contact with the point 21 and before it is accurately centered thereon, said shaft carries a toothed wheel 11 whose function it is to force arm 15 into intcrmittent contact with spring 14, thereby closing a local circuit for magnet 16 during the interval in which brush 20 is passing from one point 21 to another. The rotation of shaft 19 therefore ceases only when brush ,20 com letel covers the contact point 21 to be so ecte Upon the actuation of relay 29, contact 35 is closed and a circuit is completed from ground, through contact 35, conductor 36, sequence switch contact 105-2 and the operating magnet of sequence switch 100 to battery 5. Current in this path causes the sequence switch 100 to move to its third sition. In moving out of the second position, sequence switch contact .104-2 is opened, thus interrupting the'circuit of test relays 28 and 29. In the third position of se uence contact 115-3 is closed thereby p acing busy potential on the contact point 21 which has been selected. The circuit of

relays

28 and 29 is now connected through sequence switch contact 1043 to brush 40, which brush being in its normal osition, does not as yet complete a circuit f dr the test relays 26 and 29. In the third position of sequence switch 100, contact 101 is closed. This maintains a local circuit for the operating magnet 100, and'the sequence switch does not therefore stop in position 3, but is advanced to and stops next in position 4.

During the latter half of the movement of .the sequence switch out of position 3 contact 106-454 is closed, thus sending an impulse over conductor 41 to start the operator finder sequence switch 200 of Fig. 2, the op eration of which will be hereinafter described.

In the fourth position of the sequence switch 100, circuit is completed from battery 5 through the brush operating magnet 43, sequence switch contact 1074 and back contact 34 of relay 29, to ground. Current in this path actuates clutch magnet 43, cansing the brush carriage shaft 44 to rotate in counter-clockwise direction. As the shaft 44 starts to rotate, one of the insulating blocks point 42, and brush 40, sequence switch contact 104-4. oonductor 26, high resistance mana e coil :2? of test. relay 2;). and the coil of test relay it; to ground. delay :29 is. limverer short-circaitotl at this tinic hr a. path to g1 ounu' through contact lii -i. contact arm 35, and. tin: 'ihis h is opnn only at tic pr'r t ti to ground.

$1M? in track at, which occurs only when the brushes it). ll; i: and it) are centered on a not of illlt contacts. Test relay 1% is one iZlLi t'l'mt'ciij/ closing Contact. 39 and shunt ng the high r .anco winding 2? by the low resistance winding 31. This re- (ltitftiz the tost potoutiai on. contact 2, so that the) subscribers lino in cpiostion, cannot hr rlictett in; another switch of the group in which it terminates. When the switch lirushcs are centered on the contacts of the calling: lino. tho path to ground through rollcr 3T opons and relay it! openates thcrcl y opening tho oirnuit of clutch magnet. -13, than stopp ng the rotation of the shut: it and leaving the brushes it), &7, 16 and it in cngageincnt with the contact points 1'3, it Iii and 5; of the calling line. 'lho operation of tow rchiy Lll closcs contact 35. thus LUlltitiiilllif a circuit. from ground, through conductor Clo. scqucnce switch contact. ltltl l on the coil oi holding magnet .57, to battery. 'lhc .l'unction ol' the holding iuugnct ST is to prcicnl tho inertia of the clutch disk of tlic iirush carriage t'roni carry ing the brushes beyond tho dcsircd position. Contact 35 of relay 25) also now completes a circuit through conductor 36. sequence switch contact lt).--l and the operating magnet. of scquenco switch too to battery 5. thus moving the sequent-c switch out of its fourth and into its lifth position. In this position a. circuit is closed from ground through scquenco switch contact 100-4), rosistanco 4U. brush -57. contact. 5U of the lino tinder and the coil of count? ltllly U to bat.- tery. This opcratos the ciit oll' relay and opens the ircuit. of group relay i and line relay T. The potential of contact 50 is thus ahcrcd this changc in potential providing the busy tcst potential for the multiple con tacts oi llic calling line which may extend cithei' to nadtiple jarlt at. a. manual board or to terminals of automatic connector switches.

Scquenco switch contact. i03-5 now closed. than completing a local circuit for tripshaft opwating: magnet. iii ii way of the conta t lwtvsccn spring it and arm 15. which contact is cioscll for all positions of tho shaft 15) cxccpt the normal position. Shah It; will thus he returned to normal.

in thc fifth pa..-ition of scqaencc switch 100 the icrer of contact. Mil, which hits been standing in. an intcrinciiiatc position since the first position of he ht gli't'ilfl snitch, s moved to'its lower position in which it who pletcs connection auh coniitai'tia which extends through a tiaanictor similar to 13 and through another of sequence switch contacts similar to 102, to the sequence switch magnet of another line finder. This nil line tinder will ho operated n the niaunor as the onc described, prorioh 7 second call initiated during the use of the, first. lino tinder. This series of seqncnce switch contacts iucariied out through the entire group of lino iin-zlcr swit hes as signed to the particular gr: 3 of snlincrihcrs" lines, the number of switches depending upon the number of simultaneous calls which may he desired from a giron group of subscribers lines.

In tho fifth position of scuucncc switch 100. contacts 110 and 111 are closed. extending the line conductors to the operator tinder switch B of Fig-,2.

Tho next stop of tho linc lindcr sequence switch 100 dependent upon an impulse which vrili be rccciicil ore! conductor (30 from sequence switch 200 of Fig. 2. through sequence switch contact.--. 112 it is therefore now adrisalile to trace tho operation of the opcratous finder switch up to the point at which it, gircs the impulse mcr conductor 60 for moving the scepicncc switch 100 out of its fifth position.

As prc'riousl (lcscrihcd. scqucncc switch contact iU6 Zl l ig. l. couiplcics a circuit over conductor 41 through tho opt-rating magnet of sequence switch 200, Fig. 2. to battery and ground. The actuation of this magnet causes scqucncc switch 200m more to its second position. In this position, a. circuit is completed from battery through the coil of brush trip operating magnet (39, sequence switch contact 2U:22. and contact (:2 of test relay 63 to ground. Current in this path aotuatcs the clutch magnet 59 cansing thc rotation of the brush trip shaft (51, after the manner described in connection with Fig. 1. Carried at the top of the shaft 61. are the three brushes G5. G6 and 6? which Wipe orcr contact points conncclcd with "tll'iUllS operators listening and talking cir cuits. These circuits when idle. will have liattcry potcntial on contact points (38. so that the arrival of the brush H5 upon such a contact point completes a circuit through the coil of test relay (i3. tho coil of locking relay 64, scquonce switch contact 2U3-2, brush 65, oontact (38, sequence. switch contact. 30Q-l of Fig. 3, and the coil of signal relay 69 to battcry anl ground. Currcnt in this path actuates relays (53 and (54. lielay 69 also actuated. thereby closing the circuit from ground through contact TU. souucucc switch contact 2301-1. operating magnet of sequence switch 300, to battery and advancing this switch to its second positioii.

The actuation of relay (533 opcns its conitijiand opens the circuit. of the brush ing magnet tilt. thus flopping tho quence switch contacts 2063 and 2073 are closed at this time, thus connecting the rotation of the brushes 65, 66 and 67 upon contact points 68, 71 and 72. The actuation of test relay 63 also closes its contact position. In this position, sequence switch contact 205-3 is closed, placlng a ground potential upon brush 65 and contact point 68 to maintain the actuation of relay 69 and to furnish a busy test potential to prevent other operator finder switches from connecting with this particular operators listening and talking circuit during its use. Se

calling subscribers line through brushes 66 and 67 and contact points 71 and 72 with one Winding of the operators repeating coil 76, the middle terminal'sof this winding being connected to the opposite poles of a battery to furnish current for the calling subscribers transmitter through sequence switch contacts 3032 and 304:2. The operator is thus connected conversationally with the calling subscriber through sequence switch contact 3052 and 3062, even before anidle connecting circuit at the operators position has been selected, thus enabling the operator to obtain the number of the desired line, while the automatic selection of the connecting circuit is pro ceeding.

Sequence switch 200 does not stop in its third position, but proceeds immediately to its fourth position by reason of the closure of contact 201 during the third position. In position 4, sequence switch contact 208 is closed and a circuit is completed for the brush clutch magnet 7 7 from battery through the coil of said magnet, sequence switch contact 208-i and contact of test relay 63 to ground. This causes the rotation of the brush carrying shaft 78 in a clockwise direction, the particular set of brushes tripped during the movement by a particular finger upon shaft 61, after the manner described in connection with switch A. As these brushes 79, 80, 81 and 82 wipe over the contact points on which various cord circuits terminate, a circuit through test relay 63 is again coin leted through the various test contacts 0 the cord circuits until an idle cord is reached. As will be hereinafter explained, the test contact points 83 of all idle connecting circuits will have battery otential thereon. A circuit will, therefore,

e completed from said contact point 83, through test brush 81, sequence switch contact 2034, one coil of relay 6% and the winding of test relay 63 to ground. When the brushes first engage the connecting circuit contact relay 63 wili be short-circuited by a path to ground through contact 217 brush 253 and the interrupted track to ground, as described in connection with switch A. However, relay (34 will be encrgized, and by attracting its armature, will include its lo\\'-rcsistance right winding in parallel with its high-resistance left wind- 1ng,"thus providing a low-resistance path to ground from the contact engaged by test brush 81, and causing the multiples of that contact to test busy. \Vhen the switch brushes are centrally positioned on the contacts of the selected connecting circuit, the path to ground through the interrupter will be opened, thus actuating test relay G3. The actuation of relay U3 opens its contact 62, thusdeenergizing the clutch magnet 77. The closure of contact 75 of relay ($3 completes a circuit through sequence switch contact 209% and the winding of holding magnet 8i which on actuating, stops the brushes 79, 80,. 81. and 82 in contact with the stationary terminals of the connecting circuit. The closure of contact 75 of relay 03 also completes a circuit through sequence switch contact 204-4, and through the winding of sequence switch operating magnet 200 to more the sequence switch out of its fourth and into its fifth position. Sequence switch contact 2025 is now closed. thus completing a local circuit for trip shaft operating magnet 59 and returning shaft hi to normal after the manner described in connection with switch A. In this position of the sequenrc switch, contacts 2l0--5 and 2l1--5 are closed, completing the circuit of the calling line through brushes 79 and to the talking strands of the connecting circuit.

Upon the arrival of test brush 81, upon stationary contact point 83, a circuit is (0H1- pleted from battery through sequence switch contact 402-l, and the coil of relay 85, key contact 92, sequence switch contact 203-5, relays 64 and 63, to ground. Current through this circuit causes relay 85 to actuate, completing a. circuit through its contact 86, sequence switch contact -i031, and the coil of sequence switch operating magnet 400 to battery. This causes sequence switch 400 to move to its second position in which contacts 402'and 403 are opened. In this position contacts 410i and 4-05 are closed to connect the operators set directl with the talking conductors of the connecting circuit.

Sequence switch 400 in passing from posilamp 87 which indicates to the operator which of the particular connecting circuits at her position has been selected. In this position also, sequence switch contact if/W 2 is closed, completing a circuit through noninductive resistance 88, contact point 89 and brush 82, through selector switch sequence switch contact 21Q-Ii, and the coil of the release control relay 90 to battery and ground. Current in the path just described actuates relay ll), closing its contact 91 to complete a circuit through sequence switch contact 213----5, and the coil of sequence switch operating magnet 1300 to battery, thus moving the sequence switch 200 out oi; its fifth and into its sixth position. in moving out ofitbe fifth position, contacts 206 and 207 are interrupted, disconnecting the brushes of the opcratofis position finder from the talking circuit. In position (5 of sequence switch 200 contact is closed,

thus completing circuit through conductor 60, sequence switch contact 1125 and the coil of sequence switch operating magnet 100 to battery. This causes the sequence switch 100 to move out of its fit'th and into its sixth position. W hcu sequence switch 100 leaves its fifth position, contact 109 is opened and contact 113 4; is closed, thus shifting the control of the cutoff relay 9 from the line finder switch to the operators connector circuit, circuit being new maintained through brush 81, contact 83, series of contacts of cutoff relay release key 92, the coil of relay 85 and sequence switch contact 4OR--2 to ground, Position 6 of sequence switch 100 being the talking position, this switch is not again actuated until the release is desired.

In order that the operator may determine the number of the line which is calling, a. bank of lamps 152 or a plurality of banks of lamps is located in easy sight of the operator, these lamps being arranged in definite,

order. so that the number of any lamp which is displayed or flashed, may be readily dcterinincd From a distance. It is not always necessary for the operator to determine the niunlwr of the calling suhscribcrs line, or to verify a subscribers statement of his line number, but in order that this may be done when necessary. means are provided whereby the operator may flash the lamp 151 of the calling subscriber in the bank or banks. For this purpose the line lamp flashing key 93 is provided, which when actuated, completes a low resistance circuit through contact 89, of the connecting circuit finder, contact, '1 12 4;, brush and contact point 42 oi the line tinder switch and the coil of relay 94 to battery and ground through the back contact 53 of line relay 7. The current in this path actuatcs relay fl-l which completes the circuit of the line number lamp i751 hereby the lamp may be flashed in syn chronisin with the actuation of the operators line lamp flashing key The circuit coin iletcd in the finder switch contort-ts and it, and the branches of this circuit with their included devices, act to eiiect: two identifications of any line the terminals of which are engaged by the finder switch. The branch that is closed by way of the resistance when the line relay T is energized, cooperates with the oranch that is timed by way of the test relays 28 and to identify the line as a calling line and stop the brushes of the line finder switch in cngagena-nt with the corresponding line tcrniiinils. The branch including the relay 1H that is closed when the line relay 7 is inert, cooperates with the branch including the flashing key SE3 to identify the line to the operator as a particular one of the lines which she serves.

Furthermore, by adjusting the electrical values of the branches and the devices included in them. each branch is adapted to cooperate only with its corresponding branch. To provide the margin that do terniines the operation or non-operation of the test relay 2?, relay .94 in the normally closed branch of the conductor extending to switch terminal 42 may have a resistance of 1000 ohms, while the coil 55 included in the alternate branch of the conductor may have a resistance of 100 ohms. The margin that detcrn'iines the operation or nonoperation of the relay .l-l is obtained by making the normal path through the windings of the test relays 8 and 29 of high resistance by including a resistance 88 of, say, 400 ohms in the extension of the conductor by way of the finder switch B, and by arranging the flashing key 93 to connect the conductor directly to ground. The adjustments of the relays are such that the test relay 27 is actuated only when a line is encountered with its relatively low resistance branch closed by Way of the front contact of the line relay 7; and so that the relay 94 is actuated only when a low resistance path for the flow of current through it closed by the opcralion ot' the flashing key 93.

After the operator has terminated her conversation with the calling subscriber and has taken the first stop touard securing won ncction with the desir d suhsrrila'ns line, which may be either by means of automatic switches or a plug. and jack, she depress her listening cutolli' hey .l5 which closes a circuit throu h sequence switclr contact MEL-2, and t rough the coil of sequence switch operating magnet 400 to battery.

position. In this position, contacts 404 and 405 are opened, thus discomnrctii'sg the open ator's talhlng: and listening set of the con nwting circuit. is switch 400 passes from This causes sequence switch 400 to more out i of its second and mto its third or. tallrinn position 2 to position 3 the circuit through tlze motor magnet of operator's listening sequence switch 300 is momentarily closed throu h sequence switch contact 412-21; and t e switch returned to normal. The contact point 68 is thus again rendered selectable so that the operators position will test idle, and so that another call may he received by this operator at any one of her connecting circuits.

It is not deemed necessary to illustrate in detail the means for establishing an automatic connection or a manual connection with a desired line. It is to be understood. however, that when such a connection is established, the coil of supervisory relay 96 is senally included in the calling telephone line and the coil of supervisory relay 9? is serially included in the called telephone line, current being fed to the transmitters of the respective substations from the central source of current through these coils. At the termination of a conversation, the sub scribers replace their receivers upon their switch-hooks, and thus allow relays tit) and 97 to 'return to their normal positions, and complete the circuits of the disconnect supervisory lamps in the usual way, through sequence switch contact 410--3. When the operator observes the display of both the calling and answering disconnect lamps. she depresses her clearing out key 9 which completes a circuit through sequence switch contact 411-43. and through the coil of sequence switch operating magnet 4:00 to battery and ground. switch 400 to move out of its third and into its first or normal position. As this occurs.

sequence switch contact 410 is interrupted,

thus extinguishing the disconnect lamps. Contact 407 is now interrupted and the holding circuit of release relay thereby opened, allowing its armature to return to its normal position. closing contact 99 and completing a circuit from ground through contact 99. sequence switch contact 215 6 and the coil of operating magnet 200 to battery and ground. Current in this path actuates the sequence switch 200, causing it to move out of its sixth, and into its seventh position. Between the sixth and the seventh ositions of sequence switch 200. contact 216 is momentarily closed, sending an impulse of current through contact 112-6 and the coil of sequence switch operating magnet 100 to battery and ground. Current in this path causes the sequence switch 100 to move out of its sixth and into its seventh position.

In the seventh position of sequence switch 200 a circuit is closed for brush shaft operatingmagnet 77 from battery through sequence switch contact 208-7. and contact 62 of relay 63 to ground. This causes the brush shaft to rotate until track brush 250 This causes sequence comes in contact with plate 251, when a circuitis completed from battery through resistance 252. track 5251. track brush 250, contact arm 253, sequence switch contact 217--7 and relay G3 to ground. This causes relay ()3 to operate, opening the circuit of magnet 77 at contact (32 and closing a circuit for holding magnet. 8- by way of sequence switch contact 209 7 and contact 75 of relay 63. The closure of contact 75 also completes a circuit from ground through sequence switch contact 20=1-7 and sequence switch operating magnet 200 to battery. causing this switch to return to its normal or first position.

In the seventh position of sequence switch 100 a circuit is completed from battery through the coil of the brush operating magnet 43. contact l0T-7. and contact 34 of relay 29 to ground. Current in this path actuatcs magnet 43, causing the brush carryinp shaft 44 to rotate again in a clockwise direction. The rotation of this shaft will continue until the track brush 37 engages the plate 39, at which time a circuit is completed from battery through the resistance 73, plate 39. brush 37. contact arm 38. sequence switch contact lit-- 7, and the coil of relay 29 to earth. Current in this path iuterrupts the circuit cl? clutch magnet 43 at contact 34 of relay 29. and closes the circuit: for holding magnet 57 through contact 35 of relay 29 and the sequence switch contact 108- 7.

The actustiun of relay 29 also completes 103 a circuit through contact 35. sequence switch contact $6.1 1, and the coil of sequence switch operating magnet 100 to battery. This causes the sequence switch to step to its eighth position. in which contact 114 is 5 interrupted. permitting relay 29 to return to normal and in which contact 107 is interrupted to prevent the brush carrying shaft ll from being carried beyond its normal position. Contacts and 108 are also 110 opened at this time. the separation of contact 108 releasing the holding magnet. which now has no purpose. If sequence switch 200 has by this time returned to its normal position, a circuitis now completed through 5 contact 216--L contact 112-8. and the coil of sequence switch operating magnet 100 to battery. Current in this path actuates the sequence switch 100. causing it to move out of its eighth and into its first or normu] position, at the same time opening its contact- 112. sequence switclr 100 returns to its normal position. contact 102-l is closed. so that another call. may be. received by this line tinder switch.

It sometimes occurs that an operator will for some reason wish to hold the connection. 7 between a calling subsrribers line and one of her connecting circuits. for the purpose of, for example, notifying the calling suh 139 Scriber when a suhserihers lino which tests busy, becomes available. During this time it is nit desired that the willing suhserihors line shall, he rendered available to others desiring rounetzt iun there itfht The con nestling operator in therefore provided with eutoti' re-leaso key 92, which when aotuaten, hQVtt'h the hoiding aircuit for the nutolt' "ir la v 9 and at the name time removes the busy potential from the Contact point, 5:0 and its multiple irontart points, which may' be either the tear rout-act points of multiple jacks or the tent t'ontaet; points of an automatic eonnliuitor switrh. The operator's position is also prmided with a key lfi l whit-h when actuated, ronneeta a souri-e of current of a particular strength or wharaeiri' tn actuate, a llltSSilgt register. I

In ease the operator decides to hold the eonneetion in the al ow described manner, she will instrnet the calling Sllilht'fl'lllil' to retrain from initiating new (rail? until he s notified lay her that the dwired lino lieizanm a railabie. It; notwithstanding these in 11 ruetions. the willing Hllhstt'llni'i' does iuitiate a new rail, then, duo to the ehergizntion ot' relajr ti t the anmveringl' supervisory lamp at the operalofs p sition will be extinguinht-d. whereu 'ion the operator ran H'TUI' the eonnet-t ion that has been held by urinating her key 9 Before thus severing: the connertion. the operator ill preferably first artuate her manual listening in key (Fig. ll) to ase'rrtain whether the sub st'riher has initiated a new call, or whether he has removed hi5 receiver from the awitrhhook in answering a rail. Before signaling the railing subscriber that the called line heeanie available, the operator may actuate her manual listening in key to ascertain whether the (ailing subscriber is engaged in a conversation. It should be noted that the resistances of the repeating coil and reiay 96 (Fig. 3) are of such value that, ringing current applied to the calling line while a conneetion being held will not be diverted to an extent that would interfere with the proper operation of the bell at the suhscriberh station.

While this, inventiitin is shown and described with reference to a particular em" hodiment, obviously it, is suseepti ile of many snmlifieationn without departing from its spirit or scope.

W'lmt is elainied is:

i. In a telephone erwhange. system, the ronibinzition with lines, and a line selector having terminals tnr said lines arranged in groups, a )lurality of multiply eonneeted lHHHlIQS one .or eat'h'izroup, a brush carrier and. brush selectorineehauium of means for retnlering any of said linen seleetaliie, and. means for starting and operating said line. selertor to eonneet with a nelertahle line by ailjuntnieni of said brush selertor nierhare inn: in arrorilaniu with the group in \v'nirh the terminal of aid uelei-talil line lien and adjustment in" raid inusli Carrier in areordanre with the l lttil llil o Slili terminal in that group 2. ln a teleph ne exrliauge system. the einni inatiiui with linra and line relertor having: lin terminal arranged in (coordinate groups, a pluraln of brushes eonuerteil in multiple. a brush Carrier and a brush nelertolg of means for rendering any oi said terminals selwtalile, and means for starting and autunnitieally operating said line Selector li r aeljuntment of said lHllHil seleetor and maid brush Carrier. IKHPUUllVlLV, in areordanre with tho iot'ation of a se liittllllt terminal in said roiirclinate groups.

Cl. In a telephone exchange gram-in, the (-omliinatimi with a plurality of lines arranged in groups and a nrush carrier having a pluralit of multiply (-onneeted nets of liI'HFlHLS, of a brush selector, a eontaet meml er carried by said brush selector, Oontart points, one for watrh of said line groups adapted for eoi'iprrating with said member, and means operable by a calling line for rendering one of fittlt'i t-ontarti points selerlalile and means tor Starting and for adj1r-ting1 said brush seleetor in aeeordance with the position of said selectable Contact point.

4. In a telephone exchange system, the eonihinat ion with a line selector having terminals arranged in groups, said selector being ai'ljustahle in e ueensnive movements to eonneet with any terminal, ot a cult receiving derive for eaeh of said groups, means for rendering: any of aaid termi als selectable, and meann for operating said selector in its first movement to find a group containing a Seleetahle terminal and thereupon to (-onneet with said call receiving derive and in its second movement to ind a Selectable terminal in that group.

5. in a iQlOPliO IQ exrhange system, the emnl ination with a line RtlQfitOl having terminals arranged in groups. said selector be ing adjustable in successive movements to ronnert with an terminal, of a call receiving device for each of said. groups. means for remlering any of sa d terminals selectable, and HIPHHH tor opt-rating said fudertor in its firnt movement to find a group containing a selectable terminz'ii and tlierei'ipon to run neet with said eall rewiring clOViCi and in its second movement to find a selectable ter' minal in that. grnup and thereupon to (iiS i-nnnert said rail ret'eiving deviee,

6. In a telephone exehangz e system, a pinrality ut terminating linear operators pour tions. a telephone 9% and a group ot ennlimiting :ifl' tliim' a!" earl) nt' Raid ponitinns, means in! tlllifilllttlllilll f," wonneeting a -alling itlm to an idle one ul' mid telephone s and means For :euhseuurutly extending connecting circuits terminatln line to an idle connecting circuit associated with said telephone set.

7. In a telephone exchange system, a plu rality of terminating lines, operators positions. a telephone set and a group of con ncctiug circuits at each of said positions, means for automatically connectin 'a calling line to the telephone set of an idle operamrs position and other means for subsequcntly connecting said line with an idle connecting circuit at said position.

In a telephone exchange systdm, an operator selector switch, a plurality of groups of connecting circuits tcrminatin thereon, an operator-s telephone set individual to each of said groups, a calling line, means for extending said line to said switch, and means for operating said switch to select the roup of an idle operator and simultaneous y to connect said line with the telephone set of said operator.

9. In a telephone exchange system, a plu-. rality of terminating lines, operators positions. a telephone set and a group of connecting circuits at each of said positions, means for establishing a preliminary connection between a calling line and a'telephone set. at an idle operators position, and means for subsequently connecting said line to an idle cpnnecting circuit at said position. connecting said telephone set thereto, and breaking said preliminary connection.

10. In a telephone exchange system, an automatic switch comprising a plurality of groups of stationary contact points; a plurality of connecting circuits terminating thereon, a set of movable contact members individual to each of said groups, tripping means for bringing any of said sets into opcrative engagement with its corresponding group, an operators telephone set associated with said. group, a calling line connection extended to said switch, and contact members carried on said tripping means for completing a temporaryconnection between said calling line and said operators set.

11. In a telephone exchange system, an automatic switch, a plurality of groups of thereon, an operators telephone set individual to each of said groups, a plurality of sets of contact brushes normally held in non-contacting position, a calling line extended thereto, a brush tripping shaft with projecting members spirally positioned thereon and rotat able to bring any of said members into position for releasing a corresponding set of contact brushes, and contact members carried on said shaft for simultaneously completing a connection between said calling line and the telephone setof an idle operator and selecting the group of connecting.

circuits individual thereto.

12. In an automatic call distributing system, a plurality of lines, line finder switches,

circuit at said connecting circuit finder switches connected thereto, 0 )erators' positions, connecting circuits available at said positions and terminatin on said connecting circuit finder switc es, and meansfqr establishing a preliminary conversational connection between a calling line and an, idle operator upon the selection of said operators position and prior to the selection of an idle connecting osition. 13. In a te ephone exchange system, a line finder switch comprising a group solecting mechanism and a line selecting mechanism, a plurality of lines terminating in groups on said switch. circuit closing means rendered active by a ca-llin line and car ried by said group selector or selecting the group includmg said line, a connecting circuit finder switch, means for extending said calling line thereto, a plurality of groups of connecting circuits terminating thereon,

-an operators telephone set individual to each combination with lines, operators of said groups, and means for selecting the group individual to an idle operator and simultaneously closing a temporary by-path to said operators telephone set prior to the selection of an idle connecting circuit in said group.

14. In a telephone exchange system, con necting circuit finder switches, operators positions, line finder switches for automatically extending calling lines to said connecting circuit finder switches, connecting circuits terminating in groups on said connecting circuit finder switches and selectable thereby, an operators telephone set individual to each of said groups, an operator finder switch for each of said connecting circuit finder switches for establishing a preliminary conversational connection between a calling line and an idle operator, said connecting circuit finder switch subsequently connecting said line to an idle connecting circuit, and means for connecting said operators set to said connecting circuit and breaking said preliminary connectio 15. In a telephone exchange system, the combination with lines, operators positions, automatic switching apparatus, and means for extending connections through said apparatus between said line and positions, of means common to said ositions and controllable from an one t ereof for indicating the identity 0 a connected line.

16. In a telephone exchange sy m, the

positions, connecting circuits at said positions, means for automatically extending connection between any of the connecting circuits of any of said positions, and any of said lines, of an identifying signal individual to each line, and means at each operators position'for actuating the signal of any line connected thereto. 7

17. In a. telephone exchange system, the

combination with lines, operators positions and automatic means for distributively connecting calling lines to said positions, of means common to said positions and controllable from any one thereof for indicating the identity of a line engaged at that position.

18. In a telephone exchange system, the combination with subscribers lines, operators positions, a plurality of connectin circuits apportioned to said positions, an automatic means for distributively connecting calling lines to said connecting circuits, of an indicating signal for each subscribers line, and means at each position for actuating the signal of a calling line connected to any connecting circuit of that position.

19. In an automatic call distributing systern, a plurality of lines, operators positions, an indicating signal individual to each of said lines and common to said operators positions, and controllable at any time by the operator thereat, means at each of said positions for causing at any time the display of the signal of a line engaged at said position.

20. In a telephone exchange system, lines, operators positions, connecting circuits at said positions, means for automatically extending a callin line to an idle connecting circuit at an id e operators position, an identifying signal individual to said line, and means at said operators position for actuating said signal.

21. In a telephone exchange system. lines, operators positions, connecting circuits at said positions, means for automatically ex-' tending a calling line to an idle connecting circuit at an idle operato1"s position, an identifying signal individual to said line, and means associated with said connecting circuit and controllable at said opcrators position for displaying said signal.

22. In a telephone exchange system, lines, a plurality of operators positions. an indicating mechanism common thereto and comprising a displayable signal individual to each of said lines, connecting circuits at said operators positions, means for automatically extending a callin line to an idle connecting circuit at an i le operators position, and means at said position for controlling the signal individual to said calling line.

23. In a telephone exchange system, the combination with line terminals, automatic switches and a connection to any of said line terminals established serially through and by means of a pluralty of said switches, of means controllable over said connection for producing at will a busy or free test condition at the connected line terminal.

24. In a telephone exchange system, a plurality of lines, operators positions, an automatic switch for extending a connection from a calling line to an operators position, and means controllable from said position over contacts closed by said. switch for rendering said line available for other connections while continuing the connection already established.

25. In a telephone exchange system, a plurality of lines, operators positions, line finder switches. connecting circuit finder switches, a calling line automatically extended to an idle operators position through a line finder switch and a connecting circuit finder switch, a cutoff relay individual to said line and having its circuit carried through said line finder switch and said connecting circuit finder switch to said operators position, and a key at said position for releasing said relay.

26. In a telephone exchange system, a plurality of operators positions, a line finder switch and a connecting circuit finder switch for automatically connecting a calling line with an idle operator, a control circuit extended through said switches, and a switch in said circuit whereby the operator may render said line available for other connections while continuing the connection already established.

27. In a telephone exchange system, connecting circuit finder switches, a plurality of lines terminating thereon, operators positions. line finder switches for automatically extending calling lines to said connecting circuit finder switches, connecting circuits terminating in groups on said connecting circuit finder switches and selectable thereby, n operators telephone set individual to each of said groups, means on said connecting circuit finder switches for establishing a preliminary conversational connection between a calling line and an idle operator, means for subsequently connecting said line to an idle connecting circuit, connecting said operators set thereto and breaking said preliinii'iary connection, an identifying signal individual to said line, a cutoff relay for removing busy potential from the terminals of said line, and keys within the control of said operator for actuating said signal and releasing said cutofl' relay.

28. In a telephone exchange system, connecting circuit finder switches, operators positions, iinc finder switches for automatically extending calling lines to said connect ing circuit finder switches. con necting circuits terminating in groups on said connecting circuit finder switches and selectable thereby, an operators telephone set individual to each of said groups, an operator finder switch for each of said connecting circuit-finder switches for establishing a preliminary conversational connection between a callin line and an idle operator, said connecting circuit finder switch subsequently connecting said line to an idle connecting circuit. means for connecting said operators set to said connecting circuit and breaking said preliminary connection, an identifying signal individual to said line, a cutofi relay likewise individual to said line, and control circuits for said signal and said reiay 8X- tending through said line finder switch and said operator finder switch and controllable by said operator.

cuit and adapted for selective cooperation with said diii'crent identifying means.

30. The combination with a telephone line, of switch controlling means, a line identifying de ice, a relay for bringing said means and device alternatively into operative relation with-said line, a finder switch for making connection with said line, motor mechanism for driving said switch, switch stopping mechanism responsive to the aforesaid controlling means, and apparatus as sociated with said switch and adapted to cooperate with said identifying device.

31. The con'ibination with a finder switch having movable brashcs and a plurality of stationary terminals, of a connecting circuit extending to said movable brushes,a plurality of lines extending to said stationary terminals, a plurality of line identifying means as soriated with each line, a relay for each line adapted to control the operative connection with said line of one or another of said identifying means, and apparatus associated with said connecting circuit and adapted for selective coiiperation with the difi'erent identii'ying means of a connected line.

The combination with a finder switch having movable brushes and a plurality of stationary terminais, of a connecting circuit extending to said movable brushes, a plurality of lines extending to said stationary terminals, means for identifying each line 'withrespect to a special characteristic, means for identifying each line as a calling line. a line relay for each line for opera tivcly associating therewith one or the other of said identifying means, mechanism associated with said connecting circuit for controlling the movement of said finder switch, said mechanism being responsive to said calling line identifying means, and! apparatus associated with said connecting circuit and adapted to coiiperate with saidspecial characteristic identifying means.

The combination with a. telephone line, of a plurality of identifying means associated therewith, a connecting circuit, a

plurality of devices associated with said circuit for cooperating with said plurality of identifying means of connected line, and

neeaeeo switching mechanism adapted to associate the various novices and the corresponding identifying means with each other in' difierent staqes off the operation.

3;. he combination with a telephone line having an associated identifying conductor, of two identifying means arranged i' or alternative association with said identifying conductor, a switch for controlling said ai":riiative association of said different means with said conductor, a connecting circuit adapted to be extended to said line and having a conductor for completing the circuit of said identifying conductor, and two devices adapted to be brought alternatively into operative relation with said last-mentioned conductor, and each adapted to cooperate with a different one of said identi'iying means.

The ((Wlllllidtltlll with a telephone line having a line tcrn' inal and an associated local terminal, of a line relay, a local conductor terminating on said local terminal and having two branches of different electrical characierislics alternatively closed by said line rclz'iy, finder switch brushes adapted to'ei'igage said terminals, means for controlling the naivc'nrnt of said finder switch brushes respon ve to the closure of a pan ticular one of said branches, mechanism included in the other branch, and apparatus associated with said switch brushes adapted to cooperate with said mechanism when the rorrespomling branch is closed.

:16. The combination with a finder switch having movable brushes and a plurality of sets of stationa terminals adapted to be engaged thereby, of a connecting circuit connccted with said movable brushes, a plurality of lines connected with said plurality of sets of stationary terminals, an identity ing conductor associated with each line and connected with one terminal of the corresponding set, each identifying conductor having two branches, means associated with each line for closing one of said branches in the act of calling, means associated with said switch and responsive to the closure of said branch for stopping the brushes in engagement with the corresponding line terminals, means made operative in the engage 'ment of the brushes with said terminals for closing said other branch of the identifying conductor, and line identifying mechanism adapted to be controlled over said last-mentioned branch,

37. In a telephone system, the combination with a plurality of lines, an operators posi tion and means for automatically extending the circuit of any one of said lines to said position, of electrically actuated apparatus for giving a difierent signal indication for each of said lines, means associated with each line for rendering said apparatus operable upon the cxtenslon of the line to pro duce the signal indication corresponding to said line, and operator controlled means for efiecting the operation of said apparatus to produce the signal indication corresponding to the extended line.

38. In a telephone system, the combination with a plurality of lines, an operators position and an extension circuit for extending any one of said lines to said position, of normally inactive apparatus for indicating the identity of an ext ded line, and means controllable atany ti n ih by the operator to render said apparatus active.

39. In a telephone system, the combination with a plurality of lines, an operators position and an extension circuit for extending any one of said lines to said position, of normally inactive apparatus adapted to give a difi'erent signal indication for each of said lines, and means controllable by an operator to render said apparatus active to give the signal indication corresponding to an extended line.

40. In a telephone system, the combination with a plurality of lines, an operators position and an extension circuit for extending any one of said lines to said position, of normally inactive apparatus for indicating the identity of an extended line, means for connecting said extended line with another line, and means operable at will during the continuance of said connection for rendering said identifying apparatus active.

41. In a telephone system, the combination with a plurality of lines, of means for ex tending any one of said lines to an operators position and there connecting it with another of said lines, normally inactive apparatus adapted to give a different signal indication for each line which may be extended to said operators position, and means operable at will during the continuance of a connection for making said apparatus active to give the signal indication corresponding to the extended line.

42. In a telephone system, the combination with a plurality of lines, an operators position, a connecting circuit for extending the circuit of any one of said lines to said posiposition, said switch being ada ted to select said position and then one of t e connecting circuits thereof, a signal at said position, and means made operative upon the selection of said position for operating said signal.

44. The combination with an operators position, of a plurality of connectin circuits therefor, a switch for extending cal s to said position, said switch being adapted to select said position and then one of the connecting circuits thereof, a signal at said position means made 0 erative upon the selection of said position or operating said signal, and means actuated upon the selection of a connecting circuit for withdrawing said signal. 45. The combination with an operators position, of a lurality of connectin circuits therefor, a switch for extending cal s to said position, said switch being adapted first to select said position and then one of the connecting circuits thereof, a common calling signal at said positio an individual calling signal for each of said connecting circuits, means made operative upon the selection of said position for operating said common signal, and means actuated upon the selection of a connecting circuit for operating the individual calling signal of the circuit and withdrawing said common signal.

In witness whereof, we hereunto subscribe our names this 18th day of December A. D.,

Witnesses:

E. Emma, K. L. Sum.