US1674652A - Automatic telephone system - Google Patents

Automatic telephone system Download PDF

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Publication number
US1674652A
US1674652A US469414A US46941421A US1674652A US 1674652 A US1674652 A US 1674652A US 469414 A US469414 A US 469414A US 46941421 A US46941421 A US 46941421A US 1674652 A US1674652 A US 1674652A
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United States
Prior art keywords
relay
line
switch
circuit
trunk
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US469414A
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English (en)
Inventor
Clarence E Lomax
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Automatic Electric Inc
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Automatic Electric Inc
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Filing date
Publication date
Priority to FR550784D priority Critical patent/FR550784A/fr
Application filed by Automatic Electric Inc filed Critical Automatic Electric Inc
Priority to US469414A priority patent/US1674652A/en
Priority to GB12869/22A priority patent/GB179930A/en
Application granted granted Critical
Publication of US1674652A publication Critical patent/US1674652A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q3/00—Selecting arrangements
    • H04Q3/0016—Arrangements providing connection between exchanges

Definitions

  • the pi'esent inveiitioh relates general to automatic telephOhesy stems; but more es peciaily to, modern systen'is f the S alled tW wire type, in which the iilltoriizitie 5 switches ere controlled Over the t'WI'O side eof a. ceiling line in Series; and thefphjecfc;
  • Still other features of the invention relate to an improved control circuit for the line relay of a selector or connector switch
  • FIG. 1 shows the apparatus which is required to extend a connection from a calling station A, Fig. 1, in one of the offices or exchanges of the system to a called station A, Fig. 41, in another ofiice orexchange of the system.
  • This apparatus comprises the primary line switch P and the secondary line switch S, Fig. 1, the first selector D, and the outgoing secondary rotary line switch S Fig. 2, and the repeater B, Fig. 3, all of which are located in the origi nating exchange, together with the incoming selector E, Fig. 3, and the connector H, Fig. 1, which are located in the second exchange.
  • the selector and connector switches in all ofiices are of the Strowger vertical and rotary type.
  • calling lines are extended to first selector switches by means of primary and secondary line switches of the Keith or plunger pre-selecting type.
  • the subscribers lines are provided with individual line switches of the rotary type.v These switches have access to relatively large groups of twenty-five trunk lines each, and consequentlysecondary line switches are not necessary.
  • interoflice trunk lines extending from the originating exchange to the second exchange which are the onlyinter-o'tlice trunk lines shown, are all in a single group, this result being accomplished by the use of secondary line switches of the rotary type between the first selectors in the originating office and the outgoing trunk repeaters.
  • supervisory relay 39 of the master switch M may be considered for all practimil purposes to be directly connected to ground inasmuch as the left-hand winding of relay 39 l1as a resistance of less than 1 ohm.
  • the lower winding of the line relay 1G is also very low in resistance as stated.
  • the locking relay 11 also closes a circuit for the open main relay 1-2 which, upon energizing, disconnects the conin'ion' conductor 26Troni the negative pole of the battery in order to prevent any of the line switches nomineingoperated until the master switch comes to rest.
  • the conductors 50, 52v-and 53 of the trunk line incoming to the secondary ,l-ines'witch are extended into connectionwith the conductors 80,-"81, and 82 of the trunk line extending to the first'selector D.
  • "By theengagernent ofba'nk spring 71'With' the ban'k'conta'ct "75 a circuit iscoinpleted'over conductor-63 and through them'aster swltch wiper to the startingrelay 64 of the secondary master switch, M;
  • Theop'enmainrelay 66 is energized in parallel with the locking magnet "a'n'd jd iisconnects thecommon conductor; 62 from the negative pole of battery in order .tQPIB- vent-*the operation oifany ofthe secondary line swi tches while the i In'aste-r switch is in operation.
  • vThe callingsub'scriberl may now proceed to' opeirate his-calling device in accordance with the fir'st di'gi tin the desirednumber.
  • the energizing circuit 01'' the relay 101 is interrupted each time the line relay transmits an impulse to the vertical magnet, said relay does not fall back at this time on account of its slow releasing characteristic produced by the now short circuited lower winding.
  • This wind ing is of low resistance, preferably about 25 ohms.
  • the oil normal springs are shifted in the usual manner and by the closure of off normal springs 123 a circuit is completed for the stepping relay 103 which extends from the grounded armature 128 by way of the resting contact of saidarinaturo, the working contact of armature 114 and the said armature, armature 118 and its resting contact, ofi' normal springs 123 and the winding of relay 103 to battery.
  • relay 103 Upon energizing, relay 103 establishes a locking circuit for itself at its armature 120 over .a path which will be sufficiently obvious, and at its armature 119 prepares a circuit for the rotary magnet 106.
  • the off normal. springs 122 are closed at the same time as springs 123 and by their engagement the high resistance relay 102 is connected in multiple with the upper winding of relay 101. It follows, therefore, that each time the line relay energizes following a momentary deenergization a current impulse will be transmitted through. the winding of relay 102, but this relay is of extremely high impedance and resistance (about 5000 ohms preferably) and does not operate during the vertical operation of the switch.
  • the line relay 100 comes to rest in energized position and the circuit of relay 1.02 is permanently closed.
  • Relay 102 is accordingly energized and at its armature 1.17 opens the circuit of the vertical magnet 105, while at armature 118 a circuit is closed for the rotary magnet 106 which extends from the grounded armature 128 by way of the resting contact oif'said armature, working contact 0t armature 114 and the said armature, armature 118 and its working contact, working contact of armature 119 and the said armature, and the winding of the rotary magnet 106 to battery.
  • the rotary magnet is energized when its circuit is closed and by rotating the switch shaft one step brings the switch wipers into engagement with the first set oi bank contacts in the level. opposite which they were raised. At the same time the rotary magnet opens its interrupter contact and thus breaks the locking circuit of.
  • the stepping relay 103 which accordingly deenergizes and breaks the circuit of the rotary magnet, which then deenergizes also and again closes its interrupter contact.
  • the switching relay 104 removes the short circuit normally existing around the lower winding of the release relay 101.
  • the slow acting characteristic of the relay is thus destroyed, and the relay remains locked to the holding circuit which includes the release trunk conductor 81, current being supplied to conductor 81 through the lower winding of relay 101 for maintaining relay 104 of the selector and the holding winding 18 of the primary line switch energized.
  • the lower winding of relay 101i c1? lit der the.
  • relay 200 deenergizes momentarily three times and at each deenergization transmits a current impulse through the lower winding of relay 203.
  • the operation of relay 203 at this time is of no par ticular effect.
  • the line relay 200 opens the bridge across the trunk conductors 230 and 232 three times at armature 207, whereby three interruptions are produced in the circuit of the line relay 250 of the selector E.
  • the line relay 250 deenergizes three times and at each dcenergization closes a circuit for the vertical magnet 256 in series with the slow acting series relay 252.
  • the selector shaft is raised three steps and the wipers 280, 281, and 282 are brought to rest opposite the third level of bank contacts.
  • Relay 252 is energized in series with the vertical magnet and being slow acting retains its armature attracted during the vertical operation of the switch.
  • the oil normal springs 259 are closed and since relay 252 is now in operated position a circuit is closed through the stepping relay 254.
  • relay 254 Upon energizing, relay 254 establishes a locking circuit for itself at its upper armature and at its lower armature prepares a circuit for the rotary magnet 257.
  • theslow acting relay 252 is deenergized and closes a circuit for the rotary magnet 257, which is accordingly operated to rotate the switch shaft one step and bring the switch wipers into engagement with the first set of bank contacts in the level opposite which they are raised.
  • the rotary magnet breaks the locking circuit of the stepping'relay 254, and this relay is deenergized to open the circuit of the rotary magnet, which then deenergizes also and again closes its interrupter contact.
  • the usual trunk selecting operation is thus initiated, and in case the test contact asso-.
  • the trunk selecting operation will continue automatically, the stepping relay 254 and the rotary magnet 257 being energized alternately to advance the switch wipers step by step as long as the test wiper 281 continues to engage grounded test contacts.
  • the test wiper 281 will find no ground potential on the test contact 284, the stepping relay 254 cannot again be energized and rotation of the switch will cease.
  • the switching relay 255 which has heretofore been short circuited, is now energized over a circuit extending from the grounded conductor 231, through the winding of said switching relay 255 and by way of the interrupter contact of the rotary magnet, the off normal springs259, and the winding of the stepping relay 254 to battery.
  • Upon energizing relay the grounded conductor 231 to the test wiper 281 at armature 265 in order to make the selected trunk line busy at once, and at armature 266 closes a circuit through the upper winding of relay 253.
  • Relay 253 is accordingly energized and at armature 269 connects its lower winding with conductor 231, the said winding being, however,esh0rt circuited for the present by the ground at armature 262 of relay 251.
  • switching relay 255 disconnects the incoming trunk conductors 230 and 232 from the winding of the line relay 250 and extends them by way of wipers 280 and 282, bank contacts 283 and 285, conductors 286 and 288 and normally closed contact springs of the reversing relay 307 to the upper and lower windings of the line relay 300 of the connector H.
  • relay 253 will be deenergized, similar to the way in which relay 1010f the selector D deenergized, and will disconnect itself from conductor 231 by retracting armature 269.
  • connection has now been extended asv far as the'connector H, Fig. 4, and the calling subscriber may proceed to call the re malning two digits in the desired number.
  • Relay 302 is energized in series'with the.
  • the slow acting relay 305' is energized in parallel-with the rotary magnet 309 while the switch is rotating, and atarniature 321 connects the test wiper 352 with testrjelay- 304. Atthe same time relay 305 closes a" shunt circuitaround break contact at -arnia ture 319 of the test relay; at its armature 322,
  • switching relay 306 which "extends as follows: From ground at armature *3l2iby way of conductor 346, armature 318 and'its rest I ing 1 Contact, upper winding of the switching relay 306, resting contact of armature, 321 and th'esaid armature, test wiper 352, test contact 356', private i'iorr'n'al conductor 3Y1,
  • the switching relay 306 when the switching relay 306 is energized it establishes a locking circuit for itself at armature 326, opens the rotary magnet circuit at armature 325, connects direct ground to the test wiper 352 at armature 324, disconnects the condenser 347 from in bridge of the line relay 300 at armature 348 and at armatures 323 and 327 connects up the line wipers 350 and 353.
  • a signalling circuit is completed over which ringing current from the generator GEN is projected to operate the bridged ringer at substation A, thereby notifying the subscriber that he is wanted at the telephone.
  • the upper winding of the ring cut-otl' relay 303 is included in the signalling circuit, and when the called party r-esponds by removing his receiver the said ring cut-oft relay is operated, establishing alocking circuit for itself at its armature 316.
  • the ring cut-oil relay 303 breaks the ringing circuit at armatures 315 and 317 and at the working contacts of these same armatures finally completes the talking circuit.
  • the transmitter at substation A" is now supplied with talking current through the windings of the double wound back bridge relay 307 which is accordingly energized and reverses the incoming trunk conductors 286 and 288 as regards their connection to the windings of the line relay 300.
  • This operation reverses the "direction of current flow over trunk conductors 230 and 232, and also, therefore, the direction of current flow through the left-hand winding of the shunt field relay 1 at the repeater B.
  • This winding which is included in the circuit of the line relay, is normally energized so that the polarity of the associated left-hand magnet core is opposed in sign to the polarity of the right-hand core; that is, it the upper end of the right-hand core is positive, the upper end of the left-hand core willvbe negative.
  • the magnetic flux gener v ated will flow through the two magnet cores in series and will not effect the armature of the relay.
  • ductor 187 relays 1 and 104015 the sec ondary line switch S and the selector D,
  • Thiscircuit arrangement also 1 iti.OClUCGS a decided advantage in the case ottheplunger, type secondary line switches, such as the line switch S, Fig. 1. It hasbeeninecessary heretofore to provide aylin'e switchof this type with a low resistance slow acting relay,
  • ductors of the trunk lineextending tothe secondary line switch S is open, or if one of.
  • the locking c rcuit includes the COII1.-
  • This lamp is provided to, attract the attention of a switch-board'atten dant who, will 7 I immediately proceed to investigate the troua bleand correetit. fl f'desire'dan audible alarm ⁇ ct -somekind can beoperated at the same time; as the lamp. L in any convenient orsuitablemanner...
  • the locking circuit for the line relay or a line switch is also applicable to line switches of tlierotary type, as will be seen by referring to the circuit of line switch P, Fig; 4, Considering the line relay 362 of this switch, the armature 866, which ordinarily is connected to ground, according. to the common conductor through the low resistance supervisory relay 365 to ground, and axlowv resistance locking winding is substnv tutegd for theusual copper slug.
  • an outgoing secondary line switch of this type has been provided with a slow acting line relay, instead of an ordinary quick relay like the line relay 101.
  • This slow acting relay was provided with spring contacts for grounding a release trunk conductor, such as conductor let-7, in order to maintain the preceding selec tor switch in operated position until ground could be fed back from the repeater in the trunk line to which the connection was eX- tended.
  • the circuit of this switching mecha nism is also arranged in a special manner to take care of trouble due to open trunk lines.
  • the circuits are ordinarily intended to operate, if' the outgoing trunk line from the repeater is open, the connection from the calling sub scribe]: will not be locked up as in the preceding cases, but Wlll bedisconnectedwhen the calling subscriber hangs up.
  • the trunk line
  • the receiver is replaced the line relay 200 falls back andbreaks the circuit of the release relay 201, at the same time closing a circuit for relay 203, which energizes to open the locking circuit of relay 202.
  • the release relay 201 falls back, removes ground from the release trunk conductor 187 in order to release the preceding switches, breaks the circuit of relay 202, also the circuit of relay 203, andfinally closes the upper winding of the latter relay in bridge of the trunk conductors 230 and 232.
  • relay 203 In the event the trunk line is in operative condition, relay 203 will be held energized by means of its upper winding and the slow acting relay 202 will become unlocked, but in the present case since the trunk line is assumed to be open relay 203 will fall back immediately, and will close the locking circuit of relay 202 before the said relay has time to fall back.
  • the release trunk conductor 187 is now connected to ground by way of armatures 214C and 217, rendering the trunk line busy.
  • the line relay may now be sufficiently energized to completely attract its armature.
  • the leakage flux due to the energization of the release relay 101 assists the energization of the line relay 100 instead of opposing it, and the establishment of a buzzer action between these two relays, such as would be apt to occur if the release relay were wound in the opposite direction, is prevented- Assuming then that the line relay 100 merely energizes su'lficiently to close the three contact springs together, when the vertical magnet operates the shaft is raised one step and off normal springs 122 and 123 are closed.
  • relay 102 should pull up instantly in order to set-1 *s' at iinpirlse's, the niagiietic fluxint-heline relay builds up rapidly until therelay bec'oi'iies'satur'ated and aco'nsiderable leakage flux'win now be produced 'which'will 'efi'ect the any-102 in properi'nan'ner to hasten H Li ' fall back more its energization.
  • the scheme of so arrangingtlie polarity of the l1ne, 'rlelease, andseries relays so as to assist in the operation e fthe switch can also be applied to, an nary selector, such as the selector .13, F1 111- wh'rehfiswitch it is I, I, ⁇ H7 availed it to nnprovethe operation oi the.
  • Li telephonesysteni a group era-uni: lines, a' release trunk conductor, .eachtrunk li1ie, an automatic switch and means for operating it to connect with an idle trunk line,'a release relay in said switch lockedin e-neip'iae'd position w i'entheconnection is established, and ineanscontrolled over the selected trunk line fo'rgronnding the release 'truhlr conductor thereof to unlock said relay.
  • a trunk line a selector switch and means for operating it to connect with said trunk line, a quick acting line relay and a slow acting release relay controlling the operation of the switch, means for changing said release relay to a quick acting relay when the trunk is con nected with, a locking circuit for holding said release relay energized after its character is changed, and means associated with the said trunk line for unlocking said release relay provided the trunk line is in operative condition.
  • a subseribers individual line switch, a trunk line, subscriber controlled means including a line relay for operating said switch to extend a connection over said trunk line, means for establishing a holding circuit over said trunk line to maintain said switch in operated posi tion, means for disconnecting the line relay when the connection is extended, and a looking circuit for maintaining said line relay energized until said holding circuit is established.
  • a telephone system three serially related switches for extending a calling telephone line, a line relayin the first switch, means in the first two switches responsive to the energization of said line relay for operating said switches to extend the calling line to said third switch, means for disconnecting said line relay when the first switch is operated, means in the said third switch tor completing a holding circuit to maintain the first two switches in operated position, and a locking circuit for maintaining said linerelay energized until the said holding circuit is established.
  • a selector switch having a. primary operating magnet and a controlling line relay, a second relay for preparing a circuit for said operating magnet and for controlling the release of the switch, make before break contact springs on said line relay for controlling the primary magnetcircuit and the circuit of said second relay, and other circuit arrangements whereby the said line relay is prevented from permanently closing the circuit of the primary magnet in case said relay is only, partially energized.
  • a selector switch having a primary operating magnet and a controlling line relay, a slow acting release relay mounted adjacent said line relay, and make before break contact springs on said line relay for controlling the primary magnet circuit and the circuit.
  • release relay the said relays being wound so that when the release relay circuit isclosed by the line relay the leakage flux produced bythe energization of the release relay assists in the energization of the line relay.
  • a selector switch and a line circuit extending thereto a line relay deenergized responsive to interruptions in the line circuit for controlling the primary movement of the switch, and a second relay for starting the secondary movement having a circuit which is closed by the line relav at each deenergizationthereof, said relays being mounted adjacent one another and being wound in such directions that the leakage flux produced by the energization of the-said second relay when the line relay is deenergized responsive to an interruption assists in energizing the line relay when the line circuit is closed following the interruption.
  • a trunk line leading to an operators switchboard automatic switches for extending a calling line to said trunk line, means for automatically locking up the connection to prevent release by the calling subscriber, and means controlled by the operator for placing the release of the said switches under the control of the calling subscriber.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Telephone Set Structure (AREA)
  • Magnetic Treatment Devices (AREA)
  • Percussion Or Vibration Massage (AREA)
  • Interface Circuits In Exchanges (AREA)
US469414A 1921-05-14 1921-05-14 Automatic telephone system Expired - Lifetime US1674652A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
FR550784D FR550784A (forum.php) 1921-05-14
US469414A US1674652A (en) 1921-05-14 1921-05-14 Automatic telephone system
GB12869/22A GB179930A (en) 1921-05-14 1922-05-06 Improvements in or relating to telephone systems

Applications Claiming Priority (1)

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US469414A US1674652A (en) 1921-05-14 1921-05-14 Automatic telephone system

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US1674652A true US1674652A (en) 1928-06-26

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FR (1) FR550784A (forum.php)
GB (1) GB179930A (forum.php)

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GB179930A (en) 1923-08-07
FR550784A (forum.php) 1923-03-20

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