US1471617A - Telephone-exchange system - Google Patents

Description

a. 23, 1923. M 5 1 A. E. LUNDELL TELEPHONE EXCHANGE SYSTEM Filed Sept. 8 19 3 Sheets-Sheet 1 @cfi. 23, 1923. 1,471,617

A. E. LUNDELL TELEPHONE EXCHANGE SYSTEM Filed Sept. 8, 1917 I 3 Sheets-Sheet 2 m 1 i L A1315 E "H" -/nve afar! A Ike/7 E Lama ell.

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Oct. 23,1923. imam? A. E. LUNDELL;

TELEPHONE EXCHANGE SYSTEM Filed Sept. 8, 191"? s Sheets-Sheet 5 Patented @ct. 23, 1923.

ALBEN LUNDELL,- F NEN YORK,

iaiisii assieiqoa r0, VIESTERN nnnornrc coin- PANY, INCORPORATED, OF NEVT YORK, N. Y., A CGRPORATION OF YORK.

' r msriaoi nn2rorrs ven .siz's rniirj Application filed September 8, 1917. Serial No. 190,378.

To all whom it may concern:

Be it known that I, ALBEN E. LUNDELL, a citizen of the United States, residing at New York, ii the county of Bron and State of New York, have invented certain new and useful Improvements in Telephone-EX- change Systems, of which the following is a full, clear, concise, and exact description.

his invention relates to telephone exchange systems of the typeemployiiig niachiiie switching devices, and more particularly to systems in which the settin up of a connection is controlled solely by the call- ,ing subscriber.

Iti's the objectof this invention to provide an automatic system in which powerdriven switches may be used, and in which the selective switches are all or the same type of construction. a

A feature of the invention is the use of line finder switches of the panel type in which means are provided for rendering one only of a plurality of brush sets operative during movement of a brush-carrying shaft, such means being individual to each line finder switch.

A further feature ofthe invention is the" provision of a novel circuit arrangement whereby an allotted finder may be started an and by which the group testing operation may be accomplished.

An additional feature of the invention'is ment of the call takes place before these-' lectoi' has establishedconnection to an idle trunk. If the selector has established a coniiection'to an idle trunk, the connection at the final switch vill be completed in the usual manner and the release of the switches will be controlled in the usual manner.

It is thought th'attlieinveiition will best be understood from thefollow'ing detailed description, reference being had to the accompanying drawings. e i

In the drawings, Fig. lshows theliiie trolling circuits of a line finder switch. In

circuit of a calling subscriberand the 0011- the dotted rectangle in Fig. 1 shown an allotting switch, the position of which determines which one of aplu'rality of finders,

similar to that shown'in Fig. 1, shall be started. Intheleft-hand' portion of n ig.2 is shown a' line finder switchand an. allotte'r similar to that shown in Fig.1. In 'theright hand port-ionof Fig. Qare shown control circuits for a directively' operable selector switch; a finalswitch and the line of acaljled station being indicated tothe right of the selector'switch. In Fig. 3 are shown sender control circuits and an arrangement whereby registering switches may be set in accordance with the designation of the wanted line under the control of the calling subscriber. The wipers and contacts, shownv above the dotted lines in Fig. 3, are arranged to be controlledby a single escape magnet,

the wiper's all being mounted on the same shaft. The apparatus. indicated within the dotted lines in the lower left-hand portion of Fig; 3 is under the control of the sequence switch associated therewith. Within the dot ted lines the lowerriglit-hand portion of Fig. 8,15 shown a set ofstep-by-step regsters, a wiper, shown immediately above each stepping magnet, being individual to each such. stepp ng magnet.

The line finder switches shown in Figs. 1 p

and 2, and the selector switch shown in Fig. 2, are similar in mechanical structure to the switch shown in PatentNo. 1,123,696, issuedto E. B. Craft and J. N. Reynolds. The various controlling sequence switches are of the type shown, in Patent No. 1,127,808, issued to JTNL Reynolds 'and C. F. Baldwin, and the side switch shown in Fig. 3, is of the type disclosed in Patent No. 1,252,420,

issued January 8, 1918, to F. Forsberg.

The side switch in the present case is, however, arranged to have SlX positions and the wipers are arranged to be moved into their 7 second position upon the first eiiergization I f the escape magnet, being released into their subsequent positions upon the deencrg'lZfltlOll of the escapeinagiiet. 1

The operation ofthe system is as follows. The subscrl er, Whose substation lS'lIldltated at 11, when desiring to establish a- .13, winding of individual line relay 14, in-- ner armature and back contact of cut-01f relay 15, theloop of the calling subscribers line, outer armatureand back contact of cut off-relay 15, to ground. The subscribers. lines arranged to beserved by the line finders, similar to the line'finder indicated in Fig.1, are divided into groups, there being a relay corresponding to relay 13 associated with each such group.

7 Upon the energization of relay 13 a circuit is completed from grounded battery, lower contact of sequence switch spring 102, left and right-hand windings of relay 16 in series, lower contact of sequence switch spring 103, conductor 17, armature and front contact of relay 13, conductor 18, allotter contact 202, in position 1, normal commutator segment 19, commutator brush 20, to ground. It, is to be understood that all the line finders which serve the lines in which the calling line is included are multipled to lead 17 and thence to conductor 18 in the manner described, but, due to the action of the allotter switch 200, only one of these switches can be resting-in position 1 at any given time and, therefore, only the relay 16 associated with such allotted finder will be energizedl Upon the energization of relay 16 a circuit is completed from grounded battery, power magnet of sequence switch 100, upper contact of sequence switch spring 101, righthand armature and front contact of relay 16 to ground, for moving this sequence switch out of position 1 and into position 2, under the control of its normal spring 101.

In position 2 of sequence switch 100 a circuit is completed from grounded battery, winding of up-drive magnet 21, lower contact of sequence switch spring 10&, righthand armature and front contact of relay 7 16, to ground. When brush shaft 22 is eleiii Vvated under the control of magnet 21 it causes a plurality of brush sets, similar to the set indicated at 23, 24 and 25, to be moved into a position wherein one of them may be tripped to become operative with respect to the terminals in a contact bank of the panel type. 1

When the group test brush 20 engages the first commutator test segment26 the energiw Zing circuit of relay 16 is maintained over a I circuit from grounded battery, lower con? tact of sequence switch spring 102, windings of relay 16, lower contact of sequence switch spring 103, conductor 17, armature and back contact of group relay 13", conductor 27, commutator segment 26, brush 20, to ground. When the brush 20 engages the third commutator segment 26, which is assumed to be the segment controlled by the group relay 13 associated with the group of a calling line, the circuit of magnet 16 is opened, since the armature of relay 13 is resting on its front contactand no circuitto segment 26 can be completed. Relay 16 thereupon retracts its armature, breaking the circuit of up-drive magnet .21, thus bringing the brush shaft 22 to rest in a position wherein the third set of brushes may be tripped. The deenergization of relay 16 also completed a circuit from grounded battery, power magnet of sequence switch 100, upper contact of sequence switch spring 105, right liand armature and back contact of relay 16, to ground, for moving this sequence switch out of position 2 and into position'3.

In positions 2 to 3 of sequence switch 100 a circuit is completed for trip magnet 28 from grounded battery, winding of magnet 28, lower contact of sequence switch spring 106, right-hand armature and back contact of relay 16, to ground. The trip magnet moves a trip rod into position so that on the subsequent, upward movement of the shaft 22 the set-of brushes indicated at 23, 241 and 25 will be released.

In position 3 of sequence'switch 100 the circuit of up-drive magnet 21 is again completed from grounded battery, updrive magnet 21, upper contact of sequence switch spring 106, right-hand armature and back contact of relay 16, to ground, lVhile the test brush 25 is passing over terminal 29 of busy or non-calling lines, relay 16 remains deenergized, due to the presence of ground potential or reduced battery potential on such terminal 29. However, when the terminal 29, associated with the calling line, is engaged by the-brush 25 a circuit is com pleted from grounded battery, righthand Wlndingof relay 14, which was energized in the original line circuit, right-ha nd armature and front contact of relaylt, winding of cut-off relay 15, terminal 29, brush 25, upper contact of sequence switch spring 103, the windings of relay 16, upper contact of sequence switch 102, to ground. Relays 15' and 16 are energized in this circuit, relay 15 operating to remove the control of the line relay in the well-known manner and allow-- ing the group relay 13 to be deenergized so that other subscribers in the same group may initiate calls. The energization of relay 16 opens the circuit of up-drive magnet 21 and brings the brushes to rest in engagement with the terminals of the desired line. A circuit is at the same time completed from grounded battery, power magnet of sequence switch 100, upper contact of sequence switch spring 101, right-hand armature and front contact of relay 16, to ground, fornioving the sequence switch 100 out of position 3 and into position 13.

As soon as sequence switch 100 leaves energize when its test brushengages a multiple of terminal 29.

As soon as sequence switch 100 arrives in position 4 a circuit is completed from grounded battery, winding of relay 32, lower contact of sequence switch s ring 108, brush '24, terminal 30, loop of t e calling sub scribers line, terminal 31, brush 23, lower contact of sequence 'switchspring 109 to ground. Relay 32 is energized inthis cir cuit and completes a circuit from grounded batter winding of group relay 33, armature and [front contact of relay 32, upper contact of sequence switch spring 110, to

ground. Relay 33 is common to a group of trunks terminating in primary line finders ot the type whose operation has just been described. Upon the energization of relay a secondary line finder which has been allotted by means of an allotting switch .400, is started in the same manner in which the primary line finder was started. The opera =3 tion of the sesondaryline finder is substantially similar to that of the line finder just described.

When relay 33 was energized a circuit was completedfrom grounded battery, lower contact oi sequence switch spring 302, wind-- ings of relay 34, lower contact of sequence switch spring 303, conductor 35, armature and front contact of group relay 33, conductor 36, alotterspring 402 (in position l),normal commutator segment 37, commutator brush 38, to ground. Relay 34 upon energization completesacircuit from grounded battery, powermagnet of sequence switch 300, contact 304, right-hand armature and front contact of relay 34, to ground, for moving the sequence switch 300 out or position land into position 2, under the control of its normal spring 301 In position 2 of sequence switch 300 a circuit is completed from grounded battery, winding oi tip-drive magnet 39, lower contact of sequence switch spring 304, righthand armature and front contact of relay 34, to ground. The brush shaft 40 is elevated under the control of magnet 39 and a plurality of brush sets, similar to the set including brushes 41., 42 and 43, are moved into a position wherein they may be tripped by the action of trip magnet 44. The brush 38 tests for the group of trunks in which the incoming trunk is located, in

a manner similar to that described in connection with the line finder shown in Fig. 1. In this case it has been assumed that the incoming trunk is one of a group served by thei first brush set of the secondaryline finder, Therefore, as soon as the brush38 engages 'thetirst group test segment 645, the circuit of relay34 willbe opened,qsince relayQ33 is in an actuated condition, and relay 34 will be deenergized,- opening the circuitot the rip-drive magnet I 39 to bring the brush shaft 40 to rest in a position wherein the first brush set may be tripped At the same time [a circuit v is completed from grounded -;battery,& power,

magnet ofsequenceswit'ch 300, upper contact of sequenceswitch spring 305 righthand armatureand back contactoi relay 34, to ground, for moving this sequence switch out of position 2 and into position 3.

The deenergization of relay 34 also C01I1- pleted a-circuit for the trip magnet 44 from V grouded battery, winding of magnet 44,

lower contact of sequence switch spring 306, right-hand armature and back contact of relay 34, to ground.v The energization of the trip magnet'44 operates the tripping rod (notshown) to engage a positioned set of brushes so that on subsequent upward movement of shaft 40 they will be released into engagement with the terminals of the contact bank. I

In position 3 of the sequence switch 300 the brush rod 40 is again advanced under the control of magnet '39, the energizingcircuit for magnet 39 extending from grounded battery, winding of magnet 39, uppercon 34, to ground. ,l Vhile the test brush 43 is passing over test terminals 45, associated tact of sequence switch spring 306, right hand armature and. back contact of relay with busy or non-calling trunks, relay 34..

will not be energized, since, in the firstcase, there will be an absence of potential on the test terminals 45 and in the second case there will besuiiiciently reduced potential,

to prevent the operation of the marginal test relay 34. hen the brush 43 engages the testterminal ofthe trunk overwhich the call is being extended a circuit is con pleted from grounded battery, upper contact ot-sequence switch spring 111, winding of the relay 46, terminal 45, brush 43,'up'per spring 304, right-hand armature and front i contact of relay 34, to ground, for movv ing sequence switch 300'out 0f. position 3 and'into position 4.

In position 4v of sequence switch 300 relay 34 looks itself to ground through lLS left:- hand armature and the contact of sequence switch spring 307, thus shunting out its high resistance left-hand winding and sufficiently reducing the potential on test terminal 45 to render the multiple terminals of this trunk non-selectable to other huntcontact the energizing circuit of magnet 39.-

This magnet thereupon deencrgized, bringing' the tripped brush set, to rest on the terminals of the proper trunk.

Relay 46, when energized, locks itself to grounded battery throughits right-hand armature and front contact and at lts lefthand armature and front contact completed a circuit fromgrounded battery, power-magnet of sequence switch 100, lower contact of sequence switch 105, left-hand armature and front contact of relay 46 to ground, for

moving this sequence switch out of position 13 and into'position 14, which is the talking position.

When sequence switch 100 arrived in position 4, a circuit was completed from grounded battery, power magnet of allotting sequence switch 200, upper left-hand contact of sequence switch spring 112, allotter spring 203, to ground, whereupon allotter 200 was moved into a position to move another finder into position 1, from which position it may be started in response 3 "to the initiation of the next call. Similarly,

when sequence switch 300 arrives in posi tion' 4 a circuit is completed irom grounded battery, powermagnet of allotting sequence switch 400, lower contact of sequence switch spring 308, allotter spring 403, to ground, for moving this allotter into a position wherein another secondary line findermay be moved out of position17 and into position 18. When the sequence switch 300 arrived in position 17 upon its restoration after a precedinguse. it remained in such position until allotter 400 arrived in position 1. l Vhen the allotter arrived in position 1 a circuit was completed from grounded battery, power magnet of sequence switch 300, upper contact of sequence switch spring 308, contact of allotter spring 403, to ground, for moving sequence switch 300 out of position 17 and into position 18. lVhen' the sequence switch300 arrived in position 18 a circuit was completed from grounded battery, winding of an escape magnet 47, side-switch wiper 48 and its first contact, conductor 49, lower contact of sequence switch spring 309, to ground. The magnet 47 was energized and moved the side switch into its second position. i

Vfith the side-switch wipers in their second position a circuit was completed from grounded battery, power magnet of sequence switch 300, lower contact of sequence switch spring 305, conductor 50, wiper 51 audits second contact, sequence switch spring 515, upper armature and back contact ofrelay 60, armature and back contact ofrelay 54 to ground, for moving sequence switch 300 out of position 18 and into position 1. The subsequent operation is accomplished as set forthin the preceding description.

Tt isto be understood that in practice there would be a plurality of sending equipments, such as shown in Fig. 3, less in number, than the. number of secondary line switches, and that they would be associated with the desired link circuits by means of a cord finder switch of any desired type. This cord finder switch has been omitted in order to simplify the description of opera-- .ed battery, left-hand winding of relay 54, conductor 55. lower contact of sequence switch spring 310, brush 42, terminal 53, trunk conductor 56, upper contact of sequencc switch spring 108, brush 24. terminal 30., the loop of the calling subscribers line including an impulse sending device 57, terminal 31, brush 23, upper contact of sequence switch spring 109, trunk conductor 58, terminal 52, brush 41, the lower contact of sequence switch spring 311, conductor 59, right-hand winding of relay 54, to ground. Relay 54 attracts its armature and completes circuit for slow release relay 60 from grounded battery, winding of relay 60, ar-

mature and frontcontact oi: relay 54, to

ground. lVhen the subscriber operates his sending device 57 to send the first series of 1 impulses relay 54 is intermittently deenergized. Upon the first deenergization of re lay 54 a circuit is completed from grounded battery, winding of slow release relay 61, upper armature and front contact of relay 60, armature and back contact of relay 54, to

ground Relays 60 and 61 retain their armatures during the sending of series of impulses. The QDGI'gEZfliZlOII of relay 61 comletes a circuit from grounded batter Y winding of escape magnet 47, side-switch wiper 48 in its second position, armature and front 2 contact of relay 61, to ground. The escape magnet is energized but does not release the side-switch wipers. Each deenergization of relay 54 causes the thousands register wiper 62 to be advanced one step under the control of a stepping magnet 63, the circuit of thisstepping magnet being from grounded battery, winding of magnet 63, side-switch wiper 64 in its second position, upper arma ture and front contact of relay 60", armature and back contact of relay 1, to'ground.

After the first series of impulses has been sent relay 54: remains energized for a com- 7 paratively long periodof time and relay 61 is allowed to deenergize, causing in turn the deenergization of escape magnet 47. -lvlagnet 47, when deenergized. releases the sideswitch wipers into their third position.

The operation of setting the hundreds register'upon the receipt of the next series of impulses is identicalwiththat previously described, except that in this case the hundreds register wiper 65 is advanced under the'control of stepping magnet 66, the circuit of magnet 66 being extended through side-switch wiper 64- in its third. position,

Upon the termination of the second series of impulses the side switch is moved into its fourth position'upon the deenergization of escape magnet i? as previously. described.

"With the side-switch wipers in their fourth position the tens'register wiper 67 is advanced under the control of the stepping magnet 68 through the side-switch wiper 64:, in its fourth position, and upon the completion of thisseries of impulses, the side switch is moved into its fifth position, as

described.

V In the fifth position the side switch for.

the units register wiper 69 is positioned in 'responseto the operation of its stepping magnet 70 through the side-switch wiper 64 in its fifth position, and uponthet-ermlnation of the last series of impulses the side switch is moved into its sixth position.

When side-switch wiper71 arrived in its third position a circuit was completed from grounded battery, powermagnet of sequence switch 500, upper left contact of sequence switch spring 502, side-switch wiper 71 and:

its third contact, to ground, for moving this sequence switch out of its first and into its second position under the control ofits nor inalaspring 501. A circuit is then completed for line relay 72 from grounded battery, contact of sequence switch spring 312,

conductor 73, winding of stepping relay 74,.

left hand armature and back contact of the No. 0 counting relay, contact of sequence switch spring 503, to ground. Relays 72 and T4; are energized in this circuit,relay V 72 completing a circuit from grounded bat tery, power magnet of sequence switch300,

upper left-hand contact of sequence switch spring 313, front contact 'andarmature of relay 72, to 7 ground, 7 for moving this sequence switch out ofposition 1 into position In position 5 a-ci'rcuit is completed from grounded battery, winding of power magnet 75, right-handupper' contact of sequence.

switch spring 313, armature and front con tact of relay 72, to ground. A selector brush shaft 76 is moved upwardly under connected in such a manner as to controlthe translation of the number of the wanted line so that the proper impulses will be sent out to control 500-point switches to estab lish connection to the wantedline.

pulses is well-known in the art, ithas not been considered necessary to disclose the .wlring arrangementof the registers in the present description. If, however, we assume that the number of the wantedline' is 7823, it will be'necessary to trip'the fourth set of brushes and establish connectionto anidle trunk in the fourth subgroup of the switchshown in Fig.2; At

the final switch, which is indicated inYFEg.

, Since. the translation into the desired sets of im- 2 it will be necessary to trip the third set of brushes .and then establish connection to the fourth lincin the third sub-group served by such brush. Therefore it will be necessary to send out four incoming brush selecting impulses, four incoming group selecting impulses, three finalbrush selecting impulses, three tensselecting impulses and four units selecting impulses.

The energizing of relayfll completed a circuit from grounded battery, winding o1v the No. 3 counting relay (not shown) armature andback contact of the No. 8 counting relay (not shown) a'contact of the register controlledlby wiper 62, conductor 80, upper left-hand contact of sequence switch spring 504, armature and front contact of stepping relay 7 4, to ground. It will be remembered that the energization ofrelay 72 causedthe brush shaft 76 to be moved-upwardly. As soon as commutator brush 81 engages the first conducting segment of commutator 82.

the stepping relay 74 is shunted cover a path from grounded battery, winding of relay 72, conductor 83, lower contact of se quence switch spring 314,- commutator 82,

brush 81, to ground. The resultant deener- 'gization of stepping relay 74 allows the No;

3 counting relaylto energize in the wellknown: manner. The; countlng relays are actuated {successively asthebrush 81 successively passes over conducting; segments of the commutator 82, and whenathe O countingfl' relay is energized, the lower branch of this circuit of relay 72 is :permanently opened at the left-hand armature of the O counting relay, and when a moment laterbrush 81 engages an insulating I drive ma net 75 and brin in the brush shaft 76 to rest-in a positionwherein the fourth set of brushes may be tripped.

The counting relays, when energized, lockup to ground through sequence switch spring 505. The O counting relayat its right-hand armature completed a circuit from grounded battery, power magnet of sequence switch 500, lower contact of sequence switch spring 506, right-hand armature and tront'cont-aet of the counting relay to ground, for moving this sequence switch out of position 2 and into position During this movement the locking circuit of the counting relays is broken atsequence switch spring505 and they are restored.

The deenergization of relay 72 completed a circuit from grounded battery, winding of the power magnet of sequence switch 300, upper contact of sequence switch spring 315', armature and back contact of relay 72, to ground, for moving this sequence switch out of position 5 and into position 6.

In position 6 of sequence switch 300 a circuit is completed from grounded battery, winding of trip magnet 612, contact of sequence switch spring 31S to ground, the operation of this trip magnet resulting in the movement of a trip rod (not shown) to engage a positioned set of brushes sothat,

on subsequent upward IDOYBIHGDtOf the shaft, these brushes will be released and rendered operative with relation to the group of terminals served by them.

Provided the register setting operation has advanced to a stage wherein the side switch has reached its fourth position or some later position, thereby insuring that the hundreds register has been set, a circuit is completed from grounded battery, winding of the power magnet of sequence switch 500, the upper right or one of the lower contacts of sequence switch spring 502, and side-switch wiper 71 in either its fourth, fifth or sixth position, to ground, for mov ing this sequence switch out of position 3 and into position 4.

A circuit is now completed from grounded battery, winding'of relay 72, contact of sequence switch spring 312, conductor 73, winding of relay 74, left-hand armature and back contact of the O counting relay, contact of sequence switch spring 503, to ground. Relays 72 and 74: are energized in this circuit as before. Relay TQ completed a circuit from grounded battery, power magnet of sequence switch 800, left-handcoin tact of sequence switch spring 313, armature and front contact of relay 72, to ground, for moving this sequence switch out of position 6 and into position 7. The energi-' z'ation of relay 72 also completed a circuit from grounded battery, wind ng of the updrive magnet 75, right-hand contact of sequenceswitch spring 313, armature and frontcontact of relay 72 to ground. The selected brush set is now advanced in a group selecting'movement. The cnergization of the stepping relay 74 completed a circuit from grounded battery, winding of the No. 3 counting relay (not shown) armature and back contact of the No. 3 counting relay (not shown) through contacts controlled jointly by the thousands and hundreds registers, wiper 65, upper right-hand contact of sequence switch spring 504-, armature and front contact of relay 74 to ground. lVhen the commutator brush 84: engages a lc0nducting segment of commutator 85, the stepping relay is shunted by a circuit ex tending from grounded battery, winding of relay 72, conductor 83,'upper contact of sequence switch spring 314, commutator 85, brush 8%, to ground. The deenergization of the stepping relay 74L allows the N0. 3f counting relay to energize. The counting relays are actuated in the well-known manneiy and when the No. Q counting relay. is energized, which occurs when the selected brush is jus below the first terminal in the fourth subgroup, the lower branch of the energizing circuit of relay 72 will be broken. hen, amoment later, brush 84 engages an insulated segment of commutator 85, at which time the brushes will be accurately centered in their desired position, the relay72 is deenergized, breaking the circuit of updrive magnet '7 5 and bringing the brushes to rest in the desired position. The deenergization of relay 72 completed a circuit from grounded battery, power magnet of sequence switch 300, upper contact otsequence switch spring 315, and the armature and back contact of relay 72 to ground, for moving this sequence switch out of position 7' and intoposition 8. The encrgizatiou oi. the 0 counting relay completed a circuit from grounded battery. winding of power magnet of sequence switch 500, lower contact of sequence switch spring 506, righthand armature and front contact of the O counting relay to ground tor moving this sequence switch out of position 4 and into position 5. On leaving position 4 the locking circuit of the counting relays broken at sequence switch spring 505 and they are restored. If the register setting operation has been advanced to a stage such that sideswitch wiper 71 is in either its fifth or sixth position, a circuit will then be conujleted frorn'grounded battery, power magnet of sequence switch 500. one of the lower contacts of sequence switchspring 502, and side-switch wiper 71 in its fifth or sixth position, to ground, for moving this se quence switch out of position 5 and into position 6.

I P sition 8 o sequen e. wi ch 390, a

lit

ground.

an idle trunk.

circuit is completed .from'grounded battery,

,winding of up-drive magnet 75, left-hand cont actor sequence switch spring 316, armature and. back contact of test relay 184,-to

The selected brush set is now advanced to hunt for an idle trunk in the selected group. If we assume that idle trunks are characterized by full battery potential on their test terminals 611. and that busy trunks are characterized by reduced potential on their test it rminals, the relay 184 will I A circuit is also completed by the energization of relay 1841mm grounded battery,

power magnet of sequence switch 300, conductor 86, lower contact of sequence switch spring 319, right-hand armature andi'ront contact of relay 184, to ground, for moving this sequence switch out of position 8 and into position 10. r w I Test relav 184 short-circuited its high resistance left-hand winding through its lef hand armature and front contact and resistance 93, and the left-hand contact of sequence switch spring 317, as soon as it was energized, and after sequence switch 300 arrives in position .9, this short circuit is maintained at the upper contact of sequence switch spring 309. This short-circuitingot the highresistance left-hand winding or -re-v lay 184 suiiiciently reduces the potential .on the multiples of test terminal 611 to ren-' der the trunk line non-selectable to other testing selectors.

In position 10 of sequenceswitch 300. the control circuit is extended to a succeeding final switch over conductor 73.,through the lower contact sequence switch, v320, brush ninal 87, to a relay at the final switch,

' cponding to relay 72, to control sclec tions atsuch switch. The sender sequence switch 500 is moved through positions .6, 8

and 10 to control the selections at the final switch. I lVhen soquei'ice switch 500 ismoved out of pos tion 10 upon the lastenergization of the O counting relay. it is moved into position 14. V

lVlnle sequence SWll-Cl') 500. was passing through positions 11 to 14, a circuit is completed from grounded battery, winding of side-switch release magnet 94, conductor 95, contact of sequence switch spr ng 508 to ground; Magnet 94, upon energlzation,

its normal position, andupon locks itself to ground through its armature and front contact and oil-normal contact 96,

and causes the restoration of thesideswitch. In -position-14 offlsequence switch 50-0 a circuit is completed-from groundedbattery,

winding of stepping magnet 63 of the thousands register, its armature and back con tact, elf-normal contact 88, upper letthand contact of sequence switch spring 507, to ground. The stepping relay63 is energized and interrupts itsown circuit to advance the thousands register through a complete cycle of rotation and intoits normal position at .which time the cit-normal spring 88 will open its'upper contact and close its lower contact. Upon the closure or spring 88 upon its lower contact, a circuit is completec from grounded battery, power magnet o-fsequence switchr500, conductor 89,1ower contact of spring 88, upper left-hand contact of sequence switch spring. 507, to ground, for moving this sequence switch out of position 14 and into position 15.

- In position 15 stepping magnet 66 isoperated through the upper contact of 0&- normal spring 90 and the upper right-hand contact of sequence switch spring 507', to restore the hundreds register to itsnormal position. On reaching its normal. position the openingot. theupper contact of spring 90- prevcnts further operation of magnetefi,

and. by closing" the lower contactof spring 90 completes a circuitfor moving; the sequence switch 500 out of position 15 and into position 16. In posit-ion 16 themagnet 68 is intermittently energized to restore, the tens register throughtheunpcr contactot' ofi normal spring 91 and the lower right-hand contact 01? sequence switch spring 507, and uponits arrival in normal position, moves sequence swit h 500 into position 17, as previously described; In position-17 stepping magnet is intermittently energized through the upper contactlot off-normal spring 92 to restore the units register to its arrival in normal position, moves the sequence switch 500 out of position 17 and into position 18. i

A circuit is then completedifrom' ground.

ed battery power magnetofsequence switch 500, upper contact of sequence switchspring 506, side-switch wiper 71 and its first contact, to ground, for movingthisscquence switch out of position 18 and into position 1. 7 It is to be observedthat side-switcl1;wiper 51;, in. reaching its first contact completes a circuit from grounder. battery, power magnet of sequenceswitoh 300, lower contact of seouence switch spring 305, conductor. 50,

side-switch wiper 51 and its firstficoutact,

conductor 604, sequence-switch spring 322, to ground, for moving this sequence switch out of position .10 and into "P05111011 14,

which is the talking position, The connection is now completed and the subscribers may converse.

\Vhen sequence switch 300 arrived in position 11, supervisory relay 97 was energized the calling subscriber replaces his receiver,

causing the deenergization of relay 97,

which in turn causes the deenergization of relay 72. A circuit is then completed from grounded battery, power magnet of sequence switch 300, upper contact of sequence switch spring 315, armature and back contact of relay 72, to ground, for moving sequence switch 300 out of position 14 and into posi tion 15. A. circuit is now completed from grounded battery, winding of down-drive magnet 98, lower contact of sequence switch spring 315, armature and back contact of relay 72, to ground. At the same time a circuit is completed from grounded battery, winding of down-drive magnet 99, righthand contact of sequence switch spring 816, right-hand armature and back'contact of relay 18 1, to ground. Relay 184k was deenergi'zed when sequence switch 300 left position 14:, its locking circuit having been broken at sequence switch spring 309. The brush shafts 40 and 76 are restored under the control of magnets 98 and 99 respectively. Assuming that the brush shaft 40 is the first to reach its normal position, a circuit will be completed from grounded battery, winding of relay 72, conductor 83, contact of sequence switch spring 321, commutator segment 600, brush 601, to ground. Relay 72 is energized and opens the circuit of downdrive magnet 98. hen brush shaft 76 arrives in its normal position, a circuit is completed from' grounded battery, power magnet of sequence switch 300, conductor 86, upper contact of sequence switch spring 319, normal commutator segment 602, brush 84, to ground, for moving sequence switch 300 out of position 15 and into position 16. Since relay72 is energized, a circuit will be at once completed from grounded battery, power magnet of sequence switch 800, lefthand contact of sequence switch spring 318, armature and front contact of relay 72, to ground, for moving this sequence switch out of position 16 and into position 17.

Ifthe brush rod 76 is the first toreach its normal position, sequence switch 300 will be moved out of position 15 and into position 16, as described, and the restoration of brush shaft 40 will continue in position 16 of this sequence switch. When brush shaft 40 reaches its normal position, relay 72 will be energized and will cause sequence switch 300 to be moved out of position 16 and into position 1 by the action of the sender controlling side switch, as previously described. I

The final connecting switch 15 restored in "the well-known manner when the brush set tion 15.

In position 15 of sequence switch 100, a circuit is completed from grounded battery, the winding of down-drive magnet 603, the lower. contact of sequence switch spring 110, to ground. The brush shaft 22 is restored to its normal position under the control of magnet 603, and when it reaches its normal position, a circuit is completed from grounded battery power magnet of sequence switch 100, upper contact of sequence switch spring this sequence switch out of position 15 and into position 18. On leaving position 15 the circuit of magnet 608 is opened.

Sequence switch 100 remains in position 18 awaiting the action of allottcr 200, and when this allotter arrives in position 1, sequence switch 100 will be moved into position 1, thereby rendering the finder switch ready for reoperation. lVhen brush 25 moved off of terminal. 29, line relay 14 and cut-off relay 15 were deencrgized. All the apparatus has now been restored to normal and is ready for reuse.

If the called line is busy, a busy tone will be applied to the talking circuit by means f a busy-back apparatus at the final switch in a manner well-known in the art, and the calling subscriber upon hearing this tone will replace his receiver and cause the release of the switches as previously described.

If the calling subscriber desires to aban don the connection after his line has been seized by the line finder but before any impulses have been sent, the system will operate as follows. It will be remembered that the sender controlling side switch was moved into position 2 as soon as the secondary line finder was allotted for use by the action of allotter switch 400. Therefore, when sequence switch 300 moves into position 4 upon the seizure of the incoming trunk lineby 113, normal commutator segment 604, com mutator brush 605, to ground, for moving its associated line finder, it will immediately be moved out ofpositionl by a circuit from grounded battery, power magnet of sequence switch 390, lower contact of sequence switch spring 305, conductor 50, side switch wiper 51 in its second position, se-

quence switch spring 515, upper-back con 1 tact and armature of relay back contact 7 and armature of rela 5 to ground, and.

will come to restjin position ,lsince the sender sequence switch 500 has not been moved: out of position '1, thetundamental circuit will not be completed and relay 72 moved out of position 4:. On arriving in,

position 7' it is immediately moved into position 8 by means of the same circuit which moved it from position 5to'position 6,'and

isthen advanced out of position 8' into position 9. by means of the circuit which moveo it out of positions land 6. I

When the sequence switch 300 arrivesin position 9, since the brush rod 7 6 has not been'moved from its normal position, a circuit is completed from grounded battery, power magnet of sequenceswitch 300, conductor 86, upper contact of sequence. switch spring 319, normal segment 602, brush 84:,

to ground, for moving this sequence switch out of position 9,'through position 10 and into position 14. The sequence switchis then moved out of position 14 over a circuit from grounded battery, power magnet of sequence switch 300, upper contact of sequence switch spring 315, armature and back contact of relay 72, to ground. In position 15 ofsequence switch 300, the secondary line finder switch is restored as previously described, causing in turn the restoration of the primary line finder shown in Fig. '1.

If the subscriber desires to abandon connection after having sent in one or more sets of impulses, andprovided that the selector switch has not established connection to an idle trunk, the release of the selector switch will be as follows.

When the calling subscriber replaces'his;

receiver the relay 5a deenergizes, causing in turn the deenergization of relay 60. Since at least one set of impulses has been sent the side switch is in its third position or' some later position, and, therefore, upon the release of the-slow-releaserelay 60, a c1rcuit is completed from grounded battery,

' winding of sideswitch release magnet 94,

side=switch "wiper 610 in either its third,

tourth,1tifth or sixth position, and the lower *arinature and contact of relay '60 -to ground.

Relay 94: locks up to ground and causesthe restoration of the side switch; I

- If we assume that the selector switch is being moved upwardly in its brush-'sele'ct-i ing movement" in position" 5 of sequence abandons the connection, the brush selecting movement will be completed and the sequence switch 8 00 moved into pcsitionfi, as previously described. It 'willimmediatel switch 300at the time the calling subscriber bem'oved out of aosition 6 into position? Y Y i 7 over a circuit from grounded battery, powermagnet of ,sequenceswitch 300, the (lower, contact ofsequence switch spring 305, conductor 50, side-switch wiper 51 in its first positioinconductor 604, c0ntact of sequence i switch spring 322 to ground. Sequence switch 800 will beimmediately moved out of position 7 into position 8 over a circuit extending from grounded battery, powerv magnet of sequence switch 800, upper contact of sequen'ce switch spr ng 315, armature and back contact ofrelay 72 to ground,

and will be moved, out of position 8 and into position 9 over a circuit similar'to that just described for moving itout of position 6.

In position 9 of seque'nceswitch'300, a

down-drive magnet99, right-hand contact ground. Brush rod '76 is then restored'to its normal position under the control of circuit is completed from. grounded-battery,

magnet 99. Upon arriving in normal position', a circuit is completed byway of normal commutator segment 602' from ground- 'ed battery, power magnet of sequence swltch 300, conductor 86, upper contact of sequence switch spring 319, normal" segment 602,

sition 10. and into position 14:. From this point the restoration o'f'the selector and finder switches is accomplished as previously described.

If a subscriber replaces his receiver dur- 11,5 7

ingthe group-selecting movement oftheselector switch, the restoration of the switches will be substantially as described, but in this case the group-selectingmovement will be completed in position "7 of sequence-' movement, the sequence switch 300 will be moved out of position S'and into position 9 as described, but if a trunk has already been brush 84, toground, for moving thisfsleuence switchoutof osition 9 throu h oq P a s P no impulses to the final switch.

sized, the movement of sequence switch 300 nto position 9 will not effect the restoration of the switch, since the circuit of downdri've magnet 99 is open at the right-hand slur 'arnmturc and contact of testrelay 18 1-. In

supplied in positions 5, 7 and 9 of sequence switch 500 through side-switch wiper 71 in its first position and the upper contact of sequence switch spring 506.1":01 moving the 7 sequence switch to its various sending positions' In the normal positions of the tens andunits registers, one impulse will be sent and will allow the sending operation to continue as previously described.

If the calling subscriber replaces his re ceiver after a trunk has been seized and after the scndersequence switch has arrived in position 6, the replacing of his receiver will not allow the side switch to release, since relay 60 is maintained energized over a circuit from grounded battery, winding of relay 60, upper contact of sequence switch spring 509, to ground. ,When the sending of the impulses has been completed and sequence switch 500 leaves position 10 relay 6O deenergizes, causing the release of the side switch as previously described and allows ground to be supplied through the lower contact of sequence switch spring 322 through side-switch wiper 51 and its first contact to the power magnet of sequence switch 300, tormoving this sequence switch out of position 10, as previously described,

hat is claimed is:

1. in an automatic telephone exchange system, a contact bank, multiple terminals of calling subscribers lines arranged there in in groups, a line finder switch including a movable shaft carrying a plurality of sets of brushes resiliently secured thereto, there beluga set of brushes for each group of terminals, means tor normally retaining said brushsets in ii'ioperative position with rcspect to the groups of terminals to which they have access, means to advance said brush shaft in a preliminary movement of va'iable extent, meansoperated in accord ance with the extent of such preliminary motion to selectively trip a desiredtone of said brush sets into operative relation with respect to the grouper terminals served by switch in the,

it, and means to advance a tripped brush set into engagement with the terminals of -a calling line. I 1

2.111 an automatic telephone exchange system, a contact bank, multiple terminals oi? calling subscribers lines arranged therein in groups, apparatus individual to each of said groups, a line finder switch including a movable shaft carrying a plurality of sets of brushes resiliently secured thereto,

.' there being a set of brushes for each group sets into operative relation with the group of terminals served by it, and means to advance said tripped brush set into engage nient with the terminals of acalling line.

3. In an automatic telephone exchange system, a contact bank, multiple terminals of calling subscribers lines arranged therein in groups, a relay individual to each of "said groups, and common to all the lines of its group in a plurality of line finder switches, each of said line finder switches including a movable shaft carrying a plurality of sets of brushes resiliently secured thereto, there being a set of brushes for each group of terminals, said brush sets be ing normally inoperative with respect to the group of terminals, to which they have access, means to advance said brush shaft In a preliminarymovement, an auxiliary brush operable in response to preliminary served by it, and means to advance an operated brush set into engagement with the terminals of a calling line.

4.111 an automatic telephone exchange system, a contact bank, multiple terminals of calling subscribers lines arranged there in in groups, a relay individual to each of said groups and common to all the lines of its group, a plurality of line finder switches, an auxiliary brush associated with each of said switches and operable ;in response to movement of lts assoclated switch,

test contacts arranged to be engaged by said auxiliary brush and multipled to. corresponding contacts on the various finder switches, means to advance oneof said finder switchesin a groupselecting movement, a controll ng circuit successivelyextended to said testcontacts and'contacts'controlled by said group relays,a portion of said controlling circuit being multipled' to thearmar turesof said group relays, and means to determine the extent of said: group selectmovement in accordance with theelectri al condition of saidcontrolling circuit.

5. In an automatic .telephoneexchange system, a contact bank, multiple terminals of calling subscribers lines arranged therein in groups, a plurality of line finder: switches,

' an auxiliary brush associated with eaeh'of said switches and operable in response to movement of its associated switch, a contact engaged by said auxiliary brush in its normal position, an allotting switch common to said line finders, contacts controlled thereby, and a starting circuit. for each of said said switches and operable in response to movement of its associatedswitch, a contact engaged by said auxiliary brush in its normal position, an allotting switch common 1 to said line finders, contacts controlled therebeing multipled to the 'armatures of said Lil by, circuits controlled at contacts of said alletting switch to move an idle finder switch into a position to be started, a starting circuit completed upon initiationof a callto start an allotted finder, said starting circuit group relays and extending from a. contact of relay individual to the group 1n which the call origlnated through a contact of sald allotter switch and said auxiliary brush and,

its associated contact.

F. In an automatic telephone exchange selector switch, until after the selected final switch has been fully positioned,

8. .ln an automatic telephone exchange system, calling subscribers lines, line finder switches, selector switches, means to extend calling subscribers-line to a selector switch by means of said line finder switches, means t'otadvan'ce said selector. switch 1n:a group selecting movement, means toadvance sald selector switch in aftrunlr selecting movement, and means under the controloi' the calling subscriber to efiect the premature releaseof said switches, such means being operative only at a. time previous to" the completion of the trunk selecting movement of the selector'switch, and means operative upon such completion topreventthe release ofsaad selector switch, until after the se-.

switch, and meansoperative upon such 'CQIHPlBtlOI] to prevent the release; of said lected final'switeh has been fully positioned. i

9. In an automatic. telephone eirchange system, calling subscr bers" lines and substation apparatus, line finder switches, se-

lector switches, final switches, qmeans tov extend 'acalling subscribers line to a selector switch by means of said line finder switches, means to advance a selector switch in a group selecting movement, means control and meansto operate a final switch it said trunk selecting movement has been completed, irrespectiveof the condition of the calling subscribers substation apparatus.

10; In a telephone exchange system,an in: coming line, an outgoing line, an automatic "switchfor interconnecting said lines, a sending device, means to control said sending device, means to selectively control said switch during a portion of the operation of said sending device, circuit controlling means, release circuits controlled thereby atjcertain said switch and said sending device, and means effective under the control of sald circuit controlling means at other times to de ing device until after the. complete of said sending device. V

11. In a telephone exchangesystem, an incoming line, an outgoing line, an automatic switch for interconnectingsaid lines, a sending: device, means to operate said sending de vice, means to selectively control said switch during a portion of the operation of said sending device, a relay, release circuitsetiective upon'the operation of said relay at certain times to cause the immediate restoration of said switch and said sending device, and means effective upon the operation ofsaid relay at other times to, delay the reoperation timesto cause the. immediate restoration of ,lay the release of said switch and said send-f lease of said switch and said sending device until after the complete operation of said sendin device.

12. n a telephone exchange system, telephone lines, means to establish an interconnection between said lines by building up a connection: through a plurality of stages, means to accomplish premature release of a partially established connection prior to the accomplishment of a predetermined number of selecting stages, and means operative after the accomplishment of such predetermined number of selecting stages to prevent premature release of a connection until'after a greater predetermined number of have been accomplished. i

13 In a telephone exchange system, tele-t stages phone lines, means to establish an interconnection between said lines by building up a connection through a plurality of stages, means to accomplish premature release of a partially established connection prior to the completion of the first selecting stage, and means operative after the completion of such selecting stage to prevent premature release of a connection until after a predetermined number of stages have been accom plished.

14. In a telephone exchange system, telepho'nelines, automatic switches, a sending dev ce, means to establish an interconnection between said lines by means or" said antomatic switches under the controlof said sending device by building up a connection through a plurality of stages, means to ac comphsh premature releaseof a partially established connection prior to the accomplishment of apredetermined number of se ALBEN LUNDELL.

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