US1492868A

US1492868A - Telephone system

Info

Publication number: US1492868A
Application number: US431425A
Authority: US
Inventors: John F Toomey
Original assignee: American Telephone and Telegraph Co Inc
Current assignee: AT&T Corp
Priority date: 1920-12-17
Filing date: 1920-12-17
Publication date: 1924-05-06
Anticipated expiration: 1941-05-06

Description

May cs, 1924. 1,492,868

J. F. TOOMEY TELEPHONE SYSTEM Filed Deb. 17 1920 3 Sheets-Sheet 1 //I van for:

May 6 1924.

J. F. TOOMEY TELEPHONE SYSTEM 5 Sheets-Sheet 2 Filed Dec. 17, 1920 P19 h QM msw SN W 5 g d \\w j v I A M 3 QM QNN 1 1 6/4707 (/0/7/7 ,6 700m by a% May 6 1924.

I 1,492,868 J. F-. TOOMEY TELEPHONE SYSTEM Filed Dec. 171 1920 3 Sheets-Sheet :5

Patented May 6, 1924.

unite!) STATES? PATENT F JOHN" F. TOOMEY, or NEW YORK, ASSIGNOR'TOiAMEREGAN'TELEPI-IONE nn 'rELEeR-Arzr COMPANY, A GORPORATION on NEW YORK.

YTIELEPHONEV SYSTEM.- I

Application filed December 17,.1s2o. Serial No. 431,425.:

To all whom it may concern.

Be it knou'nthat I, JOHN F TooMEY, residing atNe'w' York, in .the county of New York and State ofNew York, have invented certain Improvements in Telephone Systems, of which the following is a specification.

This inventionre-lates to telephone systems and more particularly to systems in Which trunk lines areemployed for connecting different switchboards or operatorsv positions.

It is the customary practice in telephone exchange systems toutrunk connections for toll service from the originating switchboard or A operators position to arecording toll operators position over recording trunk lines. The recording operator answers the call incoming upon the-toll trunkand records upon a ticketthe details of the call as given by the calling subscriber and note/s it necessarythe class of the calling. subscribers line. Upon the completion of the recording, the recording operator: dismisses; the calling subscriber and in'imediately releases there cordin gtrunk. When thetrunk is released, the A operator receives a fperemptory disconnect signal and disconnects regardless of the calling subscribefis supervisory signal. The recording operator then secures the calling subscribers line over a toll switching trunk, enters the number of the trunk on the ticket and forwards the ticket to the toll operator at the toll-line posit-ion, She will then hold the trunk until the toll operator has taken up the trunk. The established connection then extends from. the calling subscribers line over the toll switching trrmlethrough the toll operators cord circult and thence over the tolllineto the desired distant point and the A operator and recording operator are free to perform other duties. I

In order that the operator at the record'- ing toll position mayhhave' complete data for recording the toll .call upon her ticket it is necessary to transmit to her information regarding the class ,of service to which the calling. subscriber is entitled. v Heretofore in exchanges, in which calling "subscribers have accessto'recording toll trunks through an ,A operators positiom the A operator has identified the class of service to which the calling, subscriber is entitled by means of a distinctive lampcap on the calling lampassoci'ated witlrthe jack of the I subscribers line and has advised the toll operatorin case the call, is from a coin box line or a line to whicha. toll connection should be refused. I

To relieve the A operator of the necessity of advising the toll operator of the class of service to which the calling subscriber is G11tltl6d.- it has been proposed to employ groups ofrecording trunks for each classof service. these trunks being equipped atthe recordingv position with different lamp. caps so that the FAl' operator can select. a: recording. trunk corresponding tow the 'class of service indicated. by thecap at the calling subscribers, line lampand thereby. call the toll operator in upon the connection through the signal displayed by the trunk lamp.

Thus the recording toll opera-tor mayreadily I determine from the lamp cap of I the trunk,

the jclass of. serviceto which. the call-ing 'subscriloer isjentrtled. Th s; arrangement obviously involves the employmentofa greater number of recording trunksthan isneces sury to adequately handle the maximum volume of-trafiic and, .sincethe toll position may be and often is" located at a distant office of theexchange, the employment of several groups oftrunks-may prove to be an expensive; item in the cost of installation and maintenance otthe system.

It istheretore the purpose of the invention to obviate this-difliculty by the employment of a single group of trunk lines over which an indicationof the class of service may befselectivelytransmitted tovv the recording.-operators,positions. -I This is accomplished .by terminating each trunk line at the originating operators position or switchboard in separate multiples for each class of subscribers and providing mechanism associated with each trunk line, for controlling the operation of class of service, signals at the jrecording position in accordance With the, multiple terminal of the trunk line which is e'mployed to establish the connection.. In the system illustrated each. trunk line terminates in four. mi'lltiples, the first for-lines which are not entitled to originate toll calls, the second for lines which are entitled to toll service and which are billed for this service in the regular way, the third for lines equipped with coin boxes, and the fourth for attended pay station lines.

An object of the invention is therefore to reduce the number of toll trunk lines re quired between switch-boards or operators positions.

A further object is the provision of means for selectively operating one of a plurality of signaling devices over a trunk line in accordance with the particularterminal employed for connection with the trunk line.

A further object is the provision of aselective signaling device at an operators position associated with and common to the cord circuits of the position which is selectively operated over a trunk circuit extending to an originating switch-board or operators position.

In accordance with one feature of the invention each recording trunk line is termi nated in foursets of multiple terminals ap peering in the terminalfbanl; of the semimechanical operators districtselector at the originating office, and in multiple lacks at the recording operators positions. Each trunk line is equipped at its out-going end with a step-by-stepselective switch which becomes positioned in accordance with the particular multiple terminal over which the trunk line is taken for use. At each recording operators position and common to the cord circuits of the position, a second step-by-step selective switch is provided which is adapted to be positioned corresponding to the setting of the first switch, for selectively operating one of a plurality of class of service signals.

Further features of the invention will appear from the following description taken in connection with the accompanying drawings in which Fig. 1 shows the out-going end of a toll trunk line together with the associated apparatus for transmitting class of service signals over the trunk line, a calling subsoribersline and a diagrammatic representation of the circuits of a semi-mechanical opera-tors position for extending a connection from the subscribers line to the toll trunk, Fig. 2 sliowsthe incoming end ofthe toll trunk; and Fig. 3 shows a cord circuit of'a. recording toll operators position together with associated class of service signals and switching apparatus for selectively operating said signals. v V

The apparatus at the semi-mechanical operators position 0 maybe ofthe general type well known in the art. In order to simplify the disclosure. the calling subscribers line A has been shown as terminating directly in a jack at the semi mechanical operators position 0. In practice, however, the subscribers line would terminate in a full mechanical switch-board and the subscriber would have access to the se1nimechanical operators position through either a line switch or line finderswitch and a. district selector, the district selector being controlled to establish the connection with a trunk circuit extending to the op erators position, through the operation of a central oliice register sender. The subscriber in order to obtain a connection with the operator therefore dials three code digits on his sender S thereby setting the district selector upon the trunk circuit extending to the operator's position. The apparatus for accomplishing this may be of the type disclosed in the patent to F. A. Stearn and F. J. Scudder, No. 1,395,977, issued Novemher 1, 1921.

It is believed that a clearer understanding of the invention may be had from the following description of the method of extending a call from the line of subscriber A to the recording toll operators position 0'. T he calling subscriber A to initiate a call removes his receiver from its switchllOOkfllQl'GbY closing the circuit of the line relay 100, this circuit extending from grounded battery through the left hand winding of relay 100. the outer armature and back contact of cut-off relay 101, thence over the subscriber line loop. and back through the inner armature and back contact of relay 101 to ground through the right hand winding of relaylOO. Relay 100 energizing in this circuit closes an obvious circuit for the'line lamp 102. This line lamp is provided with a distinctive lamp cap which enables the answering operator to determine the class of service to which the calling subscriber is entitled. In the present case it will be, assumed that the calling subscriber is entitled to regular toll service.

The semi-mechanical operator upon noting the illumination of lamp 102 inserts the answering plug P of an idle cord circuit at her position, in the jack J of the calling line, whereupon a circuit is established over the sleeve contacts of the plug and jack for the cutoff relay 101 which at its armature contacts opens the circuit of line relay100 thereby extinguishing the lamp 102.

The operator now obtains from the calling subscriber the nature of the connection which the calling subscriber desires and-assuming that the subscriber desires a toll connection she proceeds to set up upon her key board the necessary code for setting the brushes of the district selector 103, in which her cord circuit terminates, upon the terminals of a toll trunk line extending to the toll recording position 0'. The code which the semi-mechanical operator ets up upon her key board is also determined by the classof service to which the-calling subseriber is entitled, and therefore' the district selector 10 3 will not only be set by the-semimechanical sender upon the terminals of the toll trunk line, but upon a particular set of multipleterminals of the toll trun'kline for causing transmission over the toll line of a special distinctive signal for apprising the toll operator of the class of service to which the callingsubscriber is entitled. I

For tlrispurpose each-toll trunk line ter minates at the terminal bank of the district selector 103 in: four sets of terminals. In the caseassumed the brushes ofthe district selector 103 will'be set uponthe second set of

terminals

104, 105"a=nd106. A circuit is thereupon established which may be traced from battery, through the lower leftlhand winding of repeating coil 107, the winding of relay 108, the break contacts of the lower armature of reversing relay 10-9, terminal 105, brush 110, the normally closed right hand contacts ofkey 111,'the windings of polarized supervisory relay 112, the normaly closedl'eft'han'd contacts of key 111, brush 113, terminal 104, the-break contacts of the upper armature of relay 109, and thence to ground through the upper left hand winding of repeating coil 107. i

Relay 108 energizes'in this circuit and at its armature and front contact closes a circuit for relays 114 and 115which may be traced from grounded battery through the winding'ofrelay 115, conductor 116, the winding of relay 114 and thence to ground at the armature and front contact of relay 108. Relay 114 at its outer armature and front contact connects ground over conductor-117 to contact 1470f the terminal bank -1; of the step-by-step selector switch 118 and at its inner armature and front contact prepares a circuit for the reversing relay 109 which circuit is later closed in a manner to be hereinafter described. Relay 115 at its outer left hand armature and front contact establishes a circuit for the slow-to-release relay 119 extending from grounded battery, through: the winding of this relay thence to ground at the armature contact of relay 115, and at its inner left handarmature and "front contact relay 115 establishes a connection from the source of tone current 120. to the operators cord circuit atposition O. This circuit may be traced from the source 120 through the left hand armature and back contact of relay 121, conductor 122, the inner left hand armature and front contact of relay 115, conductor 153, the winding of-relay 108, the normally closed break contacts of the lower armature of: relay 109-, terminal 105, brush110 thence through the cord circuitover the subscribers line loop 113, terminal 104, the normally closed break contacts of the upper armature of relay 109 and thence to ground throughthetupper left hand winding of repeatingcoil 1.07. This source of tone current is maintained connected to the .subscriberslineuntil after the response'of the tollrecording operator and serves as a signal to 1 indicate that the recording operator is being signalled.

7 Relay 119 upon'energizing closes-a circuit for the slow-to-releaserelay 123,- extending from: grounded battery through the winding of relay 123 and-thence'to ground through the right hand armature and front contact o-f: 'r;elayi119,and at its'left hand armature opens contacts; which normally .shunt the righth'and armaturecontacts of relay 115, Slow to-re-leaserelays 119 and 128' are de;- signed slow-to-release for a purpose .Which vwill be described hereinafter. Relay 123 upon-energizing attracts its armatures, the right hand armature establishing acircuit which is- *ithout'function at this time, and the left hand armature establishing'a. circuit which may be traced from grounded battery throughthe inner'right hand armature and backcontact of relay 121, conductor 124, the 'lefthand armature and front contact of relay 123,- I conductor 125, the: right: hand armature and front contact of re1ay-"1'15,conduc* tor 126,the winding of, marginal relay 127, the lower right hand winding'of repeating coil 107, ring conductor 128 of thetoll trunk, the lower left hand winding-of repeating coil 200, conductor 201, the winding of marginal relay 202, the windings: of line relay 203, conductor 204, the upper left hand Winding of repeating coil 200, the tip conductor-129 of the toll :trunk, and thence to ground through the upper right handwinding'of re peating coil 107. Since the battery which is connected to thiscircu'itis of only 24 volts potential, and since both windings of relay 203 are included inthe circuit, neither marginal relay 127 nor marginal relay 202, receive suflicient current to energize at this time. Line relay 203, however, does energize and establishes a circuit for the trunk lamp 205 which may betraced from grounded battery throughthe armature and front contact of relay 203', conductor 206, the normally .closed' break contacts of the lower armature of relay 207, conductor208, andthence to ground through the lamp 205. 1 c r a -The operator at the recording 'toll'posi- 'tion upon noting the illuminationofthetrunk lamp 205 inserts the answering plug P of an :idle cordcircuit at her position in the multiple' jack J oftheatolltrunk corresponding to, the :illuminated lamp 205; A, circuit is thereupon established extending from grounded battery, through the winding of cult and at its upper;armatureand front sleeve rela'ySOO, the sleeve contact-s of;p1u-g contact establishes a circuit for bridging the supervisory relay 301 across the tip and ring conductors of the cord circuit, but since the circuit of relay 301 is not completed at this time relay 301 does notenergize. Relay 300 at its lower armature and front contact prepares a circuit for operating class of service signals which will be described hereinafter. =Cut-off relay 210 upon energizing in the circuit previously traced, establishes a circuit for relay 207 which may be traced from grounded battery through the normally closed contacts of the upper armature of relay 207;, conductor 211, right hand armature and front contact of relay 210 andthence to ground through the Winding of relay 207. I Relay 207 energizes in this circuit opening at the normally closed contacts of its lower armature the circuit previously traced through the trunk lamp 205, and establishes at the make contacts of its lower armature a locking circuit for itself which may be traced from grounded battery, through "the armature and front contact of relay 203, conductor 206', and thence to ground through the make contacts of the lower armature and winding of relay 207. The trunk lamp 205 now becomes extinguished. Relay 207 upon energizing also disconnects battery its upper armature contacts from its initial energizing circuit. Upon the energization of relay 210, a circuit is also established for relay 212, extending from grounded battery through the wiudingof relay 212, conductor 213, conductor 211. the right hand armature and front .contactof relay 210 and thence to around through the winding of relay 20 7. Reiay 212 does not energize in this circuit,

however. since its winding is shunted by adirect connection to ground through grounded battery; first at the upper armature con tacts of relay 207 prior to the energization of relay 207, and later by grounded battery at the armature contacts of relay 203 following the energization of relay- 207.

At its left hand armature and front con tact relay 210- also establishes a' shunt around the high resistance Winding ofrelay which shunt may be traced from the mid-point between the windings of relay 203. over conductor 214, the left hand armature and front contact of relay 210 and then'e over conductor 215 to conductor 20% and the other terminal of the high resistance winding of relay 203, and causes such a reduction in the resistance of the circuit previously traced extending through the winding of marginal relay 127 as to cause the energization' of this relay. Relay 127 at its armature and front contact estab- =lishes a circuit for relay 130 which circuit extends from grounded battery through the winding of relay 130 and thence to ground through armature and-front contact of relishes a new energizing circuit for slow-to release relay 123 extending from grounded battery through the winding of relay 123, conductor 131. and thence to ground through the left hand armature and front contact of relay 130. At its right hand armature and front contact, relay 130 establishes an obvious circuit for the sloW-to-release re lay 132, and completes the circuit of reversing relay 109. The circuit of reversingrelay 109 may be traced from grounded battery through the winding of relay 109, the front contact and inner, armature of relay 114, conductor 133, conductor 134, the armature and back contact of peremptory disconnect relay 135, conductor 136, and thence to ground at theright hand armature and front contact of relay 130. Re-

vversing relay 109 energizes in this circuit reversing the connection of battery and ground through the left hand windings of repeating coil 107 to the tip and ring conductors of the cord circuit at position 0, thereby reversing the direction of thecurrent tlowiugthrongh the windings of polarized supervisory relay 112. Supervisory relay 112 now attracts its armature in such a direction as to open the circuit which was previously established through the super,- visory lamp 137 upon the initial extension of the connection from the cord circuit to the left hand windings of repeating coil 1.07. The darkening of lamp 137. at this time. is not of any importance as the semimechanical operator does not attend furthcrto the connection. unless she is recalled by the calling operator, until she receives a disconnect signal.

The caliinrr subscriber may now transmit to the recording toll operator the necessary information concerning the desired toll conuection.

Relay 132 which becomes energized upon the energization of relay 130' following the be traced from grounded battery through the winding of relay 138 and thence to ground through the armature and make contact of relay Relay 138 at its inner left hand armature and front contact establishes a locking circuit for itself extending, as previously described, to the right hand armature and front contact of relay 123. Since relay 123 is maintained enerized over two circuits, one indirectly under the control of relay 108 in the out-going end of the toll trunk and the other indirectlyunder the control of relay 210 at the in-coming end of the toll trunlnthe locking circuit of relay 138 is therefore maintained as long as the trunk is held in service at either of its ends, and therefore ground potential is maintained at the multiran P f te tter na 6 appea ing i a l district selectors having "access to'the outgoing end of the, toll trunk. This ground potential is connected to the test terminals over a circuit eXte'ndi'ng lover conductor 139 from ground at the outer right hand armature and front contact of relay 1,38. The toll trunk is thus madeu'navailablento other outgoing calls until after it has been re; leased at both of its ends.

Relay 138 also establishes a circuit for re? lay 121 extending from groundedbattery through the winding of relay 121 and thence to ground at its inner right hand armature and front contact, and at its outer left hand armature and front contact prepares a circuit for the peremptory discon nect relay 135 which, however, is functionless so long as the slow-to-release relay 132 is maintained energized. V

Relay 121 upon energizing-opens the previously traced circuit from thevtone source 120 at its left hand armature and back contact and at its intermediate right hand armature and front contact establishes a stepping circuit for advancing the stepV-by-step selective switch 118. This stepping Icircuitmay be traced from grounded battery through the Winding of motor magnet140, conductor 141, the inner right hand armature an back contactof, stop relay 142, the front contact and intermediate right hand: arm-ature of relay 121 conduct0r143, and thence to ground through the interrupter 144. Under the influence of motor magnet 140, the wipers 145 and 148 of switch'118 are ad'- vanced over the contacts of the 1761111111211 banks a and b, with which they are asso ciated, until the wiper 145 engages thecon'ltact 147 in the bank a-. towhich ground potential has been connected over conductor 11? and the outer armature and front contact of relay114, when acircuitis established for the stop relay 142, which may, be traced from groundedbattery through the right hand winding of relay 142, conductor 146, wiper 145, contact 147, conductor 117, and thence to ground of the armature contact of relay 114. Relay 142 energizes in this circuit establishing a locking circuitfor itself extending from grounded battery through its left hand winding and itsleft hand armature and front contact and thence to ground at the outer right hand armature and front contact of relay 121,.and at its inner right hand armature. and back cgnfiact opens the previously traced circuit extending through the winding of motor magnet 140. The initial energizing circuit of mag net 140 is now open'but Ina-gent 140 continues to be intermittentlyenergized overa'circuit which may be traced from grounded battery through the winding of magnet. 140., wiper l48 ,tthe contacts of bank dconductor 143 nd thenceto ground through th inte ruuter leiiaa th w pers of switch 111.8 there ore l il f t dvance nt they er ag in t e ,o m'a pos tions nh circuit just traced for magnet 140 is opened and the'i'vip'e'r's are arrested in theirflforward movement. v Q l v i \t tl 1etime relay 12 1 energizes to close the starting circuit (if-selective switch 118, h init a e r zing new. p evious y traced through the windings oflfilays 127, 203 and 2024s OP-G'nedat the innerfright hand armature and back contact of relay 121 and a new energizingcircuit forthe'se relays is establish d ex nd ng from the groun ed pole of the 48 volt battery 149, the outer righthand armature and baek contacto'f relay 142, the inner right hand armature and front contact, Qfirela-y 121: and thence over the circuit previously traced, through the windings of relay l27 and 203 and marginal relay 202. Since current isnow supplied to this circuit fromr the 48 volt battery"149 sufiicient current flows through the winding of marginal; relay 202 to caus its'energiza- 'tion and relay 2 02 continues to remain energized until the'wiper 145 of switch 118 chcounters the contact 147 to close the energizing circuit of relay 142 as previously described. f I

Relay 202 upon I energizing closes a circuit for relay 216 which maybe traced from grounded battery through-the winding'of relay 216i and thence to ground atthe armanu-e fianid contactoi 'jrelay 202. Relay 216 upon energizing coiinectsthe windings of retardationcoil217to the tip and

ring con du'ct'ors

218 and 219 of t h'e in-coming end ofthe toll trunl; 'lineth'ereby establishing a simplex circl'jit'which may "be traced from grounded battery through the winding of relay 302, conductor 303, thence in parallel -hrle ieh t e r t da ion co s 4,1 c cr tors B05 and .306, normally closed contacts of the talking zey 307, tip and ring strands 308; and 309 at theanswering end of the cord circuit, tip and ring contacts-of the plug P and jack J,

trunk conductors

218 and 219, the armatures and backifcontacts "of relay 212', the a rmatures an d front contacts of relay" 216 and thence to .g'ro-undat the midpoint between the windings of retardation coil 217. Relay 302'energizes in this circuit and at its right .hand armature and front contact establishes a starting circuit for. the motor magnet 310' of the .s't'ephy-s'tep selectii te switc,h;311, which circuit may he traced rlirom gnounded batt-erythrough the winding of motoruniagnetfilO, the right han'd armature and: front' contac t -f rela;y,302 the armature and back contact of stop relay 312 and thence to ground through the interr rupterJBI-T-K. Ilnder'the influence of interrupter 323; the motor magnet 310 "advances the wipers 314,-and 315,over the contacts of the terminal banks c, (I. During the advance of the wipersof the switch and so long as relay 302 remains energized battery potential is disconnected from the wiper 314 at the left hand armature and back contact of relay 302.

When the wiper 145 of the selective switch 118 engages the contact 1 17 which corresponds to the second set of switching terminals over which the semi-mechanical operatorhas seized the toll trunk, relay 142 energizes in the manner previously described and at itsouter right hand armature and back contact disconnects the 48 volt source of current 149 from the circuit of relay 202 and substitutes a 24 volt source of current therefor, whereupon relay 202 deenergizes opening the circuit of relay 216 and thereby opening the simplex circuit ex tending through the winding of relay 302 at the tolloperators cord circuit. Relay 302 therefore deenergizes immediately upon the setting of the selective switch 118 in a position corresponding to the particular set of switching terminals over which the toll trunk was seized and opens the stepping circuit of motor magnet 310 to arrest the movement of wipers 311 and 315. The wiper 314 will now be in contact with the contact 316 and a circuit is established extending from grounded battery through the left ,hand armature and back contact of relay 302, the left hand armatureand back contact of relay 312, wiper 31 1, contact 316, conductor 317 the normally closed break contacts of the right hand armature of relay 318, the winding of relay 318, the normally closed break contacts of the inner left hand armature of relay 318, conductor 319, contacts 320 of the talking key 307, andthence to ground at the lower armature and front contact of relay 300. Relay 318 energizes in this circuit and establishes a locking circuit for itself independent of the wiper 314: and contact 320 of key 307 which locking circuit may be traced from grounded battery through the winding of stop relay 312, conductor 321. conductor 322, the right hand armature, and make contact of relay 318, winding and left-hand armature and make contact of relay 318, conductor 323, and thence to ground at the lower armature of relay 300.

Relay 312 energizes in this locking circuit and at its armature opens the initial circuit of motor magnet 310 and closes a new circuit for continuing the advance of the wipers 311 into their normal positions, which circuit may be traced from grounded battery through the winding of motor magnet 310. conductor 324, wiper 315, the contacts of terminal bank -d-, the armature and front contact of relay 312 and thence'to ground through the interrupter 313. During the advance of the wipers to normal position battery is disconnected from wiper 314 atthe left hand armature of relay 312. As soon as the wipers reach their normal positions, the advancing circuit just traced through motor magnet 310 is opened at the wiper 315 of the switch, and the advance of the switch wipers is thereupon arrested.

Upon the energization of relay 318, a circuit was also established for the class of service pilot lamp 325 which may be traced from grounded batterythrough lamp 325, the outer left hand armature and front contact of relay 318, conductor 319, contacts 320 of talking key 307, and thence to ground at the armature and front contact of relay 300. The lamp 325 will be provided with a lamp cap which is distinctive of all calls incoming to the toll operators position which are entitled to regular toll service, and the toll operator, noting the ilhunination of this lamp, and upon receiving instructions from the calling subscriber as to the toll connection desired, will thereupon make out a suitable ticket for billing the connection to the callingsubscriber. She will then dismiss the calling subscriber and immediately release the recording trunk by withdrawing plug P from the jack J.

After having obtained the necessary information from the calling subscriber, the recording toll operator may disconnect her Set from the'cord circuit which she has employed by throwing the key 307 to its intermediate position. The contact 320 of the key is now opened and the circuit previously traced through lamp 325 is opened and the lamp is extinguished. If at any time, while the plug P is in the jack .1, the operator desires to relight thelamp 325 to check up the class of service to which the calling subscriber is entitled, she may do so by operating the key 307 to the talking position thereby reestablishing the circuit of lamp 325 at key contact 320.

It is to be noted that four relays comprising a group of which 318 is a part are provided for each cord circuit atthe. operators position, the relays of each group controlling the circuits of a single common group of class of service pilot lamps. The several groups of relays are under the control of a single step-by-step selective switch 311, which is common to all of the cord circuits of the operators position.

If the calling subscriber had not been entitled to toll service, the semi-mechanical operator at position 0 would have set the district selector 103 upon the first set of terminals of the terminal bank, and selective switches 118 and 311 would have advanced to such positions as to have caused the energization of relay 330 at the operators position O and the consequent illumination of pilot lamp 331. Similarly, if the third or fourth set of switching terminals had been selected, relays 332 or 333 at the toll recordis now reduced to such a strength that marginal relay 127 at the out-going end of the toll trunk does not receive sufiicient current to maintain its ener ization, whereupon the circuit of relay 130 is opened, in turnopening the circuit of reversing relay 109 and the circuit of slow-to-release relay 132. Relay 132 upon deenergizing opens at its armature and front contact the initial-energizing circuit of relay 138, but relay 138 is main-' tained energized at this'time over a circuit extending to ground at the right hand armature andfront contact of relay'123. At the normally closed contacts'of its armature, relay 132 establishes a circuit extending from grounded battery through the interrupter 150, thewinding of peremptory'dise connect relay 135, the outer left hand armature and front contact of relay 138 and thence to ground at the armature contacts of relay 132. Relay 135 now being intermittently energized closes intermittently a circuit for reversing relay 109 extending over the circuit previously traced to the armature of relay 135 and thence to ground at the front contact of this armature. Relay 109 is now intermittently enere gized to reverse the current flowing over the out-going end of the toll trunk through the windings of polarized relay 112 whereupon relay 112 causes the flasliingqoi supervisory lamp 137.. 1

The semi-mechanical ope-rator'noting the flashing of lamp13j7 removes the plug P from the jack J of the calling line thereby restoring the calling line to its initial condition and causing the restoration Ofthe district selector Switch 103. Following the restoration of switch :103, the circuit previously traced through the winding of relay 108 is opened thereby opening the circuit .of relays ll land 115. I Relay 115' upon deenergizing opens the circuit of relay 119, which in turn opens the circuit of relay 12,3, and since at this time the auxiliary holding circuit of relay 123 previously traced over conductor 131 is open at the armature con.- tact ofrelay 130, the trunk having'b'een released at this time at its in-coming end, relay 123 deenergizes opening at its right hand armature contacts the holding. circuit of relay. 1 3'8,:'whi.ch in turn opens the @circ-uit'of relay 12.1;and removes busyqgr'ound"poten-- tial 1. 1'O111tl16 conductor 139' and thevinultie pleterminals of the toll trunk. Relay-121 upon deenergizing opens the locking circuit of'rela-y 142. The circuits at the out-going end of the toll trunk are now int-hei-rhormal position. I

Relay 115 upon deenergizing also opens the circuit, previously-traced extending over the-toll trunk and through the windings of

relays

203 and 202 and relay 203 now deenergizes opening the locking circuit of relay 207. Relay 210 being at this time deenergized, the deene-rgization of relay 207 is not effective to again close its .own energizing circuit previously traced from grounded battery through its upper armature contacts and over conductor 211. The apparatus, at the iii-coming end of the toll trunk -is;now in its normal position andall of the'apparatus employed for the establishment of the connection is now restored.

The recording toll pperator having re.- leased the recording trunk proceeds to see cure aconnection in the usual manner with the calling subscribers lineAover atoll switching trunk (not shown), and {having obtained the calling subscriber7s line holds the connection by inserting the plug of holding cord circuit (not shown) into the jack of the switching trunk and records the number ofthe switching trunk onthe ticket which she previously made out. She then transmits the ticket in the routine manner to the regular toll line operator who has access to multiples of switching'trunks and to toll lines. The toll line operator, after receiving the ticketproceedsto obtain the desired toll connection and upon getting-the connection, connects the calling subscriber to it over a multiple of'the switching trunk. As soon as-the connection is established, the .toll recording operator receives a disconnect signal. at her holding cord and proceeds to take it down. Inasmuch as this invention does-not involve a consideration of the establishment of connection beyond the recording operators position, the other circuits employed in the complete establishment of toll connection have not been disclosed .01

described in detail herein.

The recording toll operator also has ac cess to tie lines extending to the information desk, rate-quoting desk and other traflic desks of the oflice and-may when requested by the calling subscriber complete connections to such tie lines b inserting the plug Pin the jack J of such a line. Upon the insertion of plug P in the jack J a circuit isestablished for sleeve relay 5326 which may be traced from I grounded battery through the winding of. relay 326 and thence to ground through the sleeve contacts of-the plug and jack. Relay 326 upon energizing establishes a circuit for bridging supervisory relay 327 across the strands of the cord circuit, which relay controls the circuit of lamp 328 in the usual manner.

If for any reason, the tollrecording operator at position desires to recall the semi-mechanical operator at position 0, she may do so by temporarily withdrawing and inserting the plug P from the jack J. Upon each temporary 'withdrawal of the plug from the; jack, the circuit of sleeve relay 210 is opened to remove the shunt from around the high resistance winding of relay 203. thereby decreasing the strength of the current flowing oy er the conductors of the toll trunk and through the winding of marginal relay 127. Relay 127 therefore'deenergizes upon each withdrawal of the plug P; from the jack J and at its armature contacts opens the circuit of relay 130 which in turn opens the circuit previously traced through the winding of slowto-release relay 132 and reversing relay :9.

Relay 132, however, being"slow-to-release s does not have sufficient time to restore its armature contacts to their initial position between the successire deenergizations of relay 127. and therefore the circuits which are established'by relay 132 aremaintained in their operated ccndition. Relay 109, however, responds to each deenergization of relay 130 and at its armature contacts reverses the current flowing through the windings of polarized supervisory relay 112 at the semi-mechanical operators position 0. The current now flowing through the windings of relay 112 is in such a direction as to cause the closure of the circuit through lamp 137, and lamp 137' thereupon flashes in synchronism with the intermittent withdrawal of "the P from the jack J.

In response to this flashing signal, the semianechanical operator reconnects her set with the semi-mechanical cord and is then in communication with the recording toll cperator';

The semi-mechanical operator may recall the recording toll operator by throwing the key 111 to its alternate position in which 7 position the windings of relay 112 are disconnected from the strands of the semilmecha nical cord circuit and battery and ground are connected respectively to the ring and tip [conductors of the out-going end of the toll trunk. Therefore upon the operation of the key 111. the circuit of relay 108 is rendered ine'tfective thereby opening the circuit previously traced through the windings of relays 114 and 115. Relay 115 upon deenergizing opens at its" outer left hand armature the circuit previously traced for the slow-torelease relay 119 but since relay 119 is slow-to-release it does not have sufficient time to releaseits armature during the operation of the key. Should relay 119, however, release its armatures to open the circuit of slow-to-release relay 123,

i the relay 123' being slow-to-release would not open at its armature contacts the circuit previously traced through the windings 'of

relays

127, 203 and 202 duringthe op eration ofkey 111. Relays 119 and 123 therefore afford a slow acting means for holding the circuit of relay 127, 233 and 202 closed at the armature contacts of relay 123 during'the operation of key 111. Upon the deenergizaticn of relay 115 the circuit previously traced through the winding of relay 203 is opened at this right hand contacts of relay 115 and relay 203 deenergizes, and at its armature contacts opens the shunt previously traced around the winding of'relay 212. Relay 212 thereupon energizes to connect battery and ground through the windings of retardation coil 220 to the ring and

tip conductors

219 and 213 respectively of the toll trunk.

In response to the connection of battery andground to the conductors of the *in coming end of the toll trunk, a circuit is established for the bridged relay 301, which circuit mayzbe traced from grounded battery through the lower winding of retardation coil 220, the lower armature and front contact of relay 212, conductor 219, ring contacts of jack J and plug P, conductor 309, the upper armature and front contact of sleeve relay 300, left hand windingof relay 301, conductor, 308, tip contacts of plug P and jack J, tip conductor 218 of the trunk circuit, the upper armature and front contact of relay 212 and thence to ground through the upper winding retardation coil 220. Relay 301 upon energi'zing closes a locking circuit for itself extending from grounded battery through its right hand winding, armature and front contact, and to ground at contact 336 of the talking key 307. the talking key 307 being at this time in, its intermediate position in which the operators set 329 is disconnected from the strands of the cord circuit. Relay 301 also closes a circuit from ground at contacts 336 through the recall lamp 337 to grounded battery. The operator-noting the illumination of lamp 337 is advised of the fact'that the semi-mechanical operator is trying to recall her and she thereupon operates the key 307 to the'talking position in which position the OlIClllll Of lamp 337 is opened and the locking circuitof relay 301 is disestaiolished. At the semi-mechanical operators position, upon the restoration of the recall key 11Lto its initial position, the circuits of relays 108, 114 and 115 are again established. 5 I

If the calling subscriber abandons the call before the extension of the connection to the recording operators cord circuit and before the recording operator releases the recording trunk, the semi-mechanical oper-- ator at position 0 in response. to ther usual supervisory signal proceedsto withdraw the plug P from the'jack J whereupon the calling subscribers line is restored toits nor.- mal condition and thedistri-ct selector 103 is restored. Upon the restoration of the district selector, the circuit previously traced extending through relay- 108 is opened and relay 1,08 upon deenergizing opens the circuit of relays 114i and 115. Belay 1'15 upon deenergizing opens the circuit of relay 119 which in turn opens the-circuit of relay 123. Relay 123,however, does not deenergize until after the trunk circuit is released at its incoming end. Relay 115, upon deenergizing, momentarily opens the circuit previously traced through the windings of relays 127, 203" and 202 and these relays deenergize. The; deenergizationof relay 203 opens the shunt around the- Wind.- ing of relay 212- and relay 212 thereupon energizes connectingbattery and ground through the windings of retardation coil 220 to thering and tip conductors 21*8and 219 of the trunk circuit as previously described. A circuit is now established for supervisory relay 301 at the recording toll operators cord circuit in the manner previously described for establishing the circuit for the recall'lamp 337. The recording operator noting the illumination of lamp 337 proceeds to take down the connection by withdrawing the plug P from theqack J.

Upon the withdrawal of plug P from the jack J, the circuit of sleeverelay 300 of the cord circuit and relay 2100f the trunk circuit is opened." The deenergiz-ation of relay 300 opens the locking circuit of relay 318 and opens the circuit of supervisory relay 301. The circuits of the tolloperators cord circuit are now in normal condition.

Relay 210 upon deenergizing opens the locking circuit of relay 207 extending to grounded battery through the winding; of relay- 212, and these relays become oleener- -gized thereby restoring the circuits-cat the in-coming endot the trunk circuit to normal position; The deenergization of relay 2l0 also removes the shunt from around the high resistance winding of relay 203thereby decreasing strength of the current flowing-through the winding-of relay 127 at the out-going end of the trunk circuit to such an extent that relay 127 deenergizes opening the circuit of r'elay130, which relay in turn opens the circuit of relay 1'32. Belay "Relay 203 thenbecomes deenergized. Upon the'deenergizatio'n of relay 123, the locking "circuit of relay "138. is opened and this relay een rgiz op ng he ci cuit at re ay I2 andv disconnectin 1g ground; potential from they multiples; of test terminal 10,6 -whereby the toll trunk is made available for other:

calls ler 12 po deenersi g Opens the locking-v circuit of relay 142.- All-the:

circuits which have been employed in the toll trunk and. a set ofswitching termina-ls of the toll trunk corresponding to the class oil service to. which the particular calling subscriber is entitled ll" be automatically selected in any suitable manner; Fullmechanical connections to'thetoll trunk could be established; in substantially the same manner as shown, and: described in the patent to F. A,. Stearn and: F. -J.;Scudder hereinhefore referred to. i

The calling trunks may also terminate in a plurality of multiple jacks at manual 0 I craters positions in the manner: disclosed. In my copending application I Serial No. 431,424, filed December 17,1920;

It is, of course, obvious that should: it be desirable to operate a larger'gronp of class of service pilot signals atthe toll. operators position, it would only be necessary to supply more sets of switching'terminals at the outgoing end of. the toll trunk and to-equip the stepby-step selective switchcs1118 311 with a number ofsele'ctive positions corresponding to-the number of switching teriminals and to thedesired number of pilot signals. I Y

Whatisclaimed' is;

1.v A telephone exchange system comprise ing' atrun k circuit terminating at its outgoing end in a plurality of sets oiswitching' terminals, a. connecting circuit, switch- 111g apparatus associated W1ththe trunk 011- cui-t having "selective positions correspondmg in number-to said setsiofr switching .termrnals, means operative upon the connection ofhsai dconnecting circuit with a set :of

switching terminals for controlling said switching apparatus, a plurality'of signalling "devices, switching apparatus associated'with the incomin-gaiend of said trunk circuit. and operative ignj'accordanceswith said 1 first named switching apparatus for openatin'gone of said signalling devices-and means. at the incomingend of said=trunk Icircuit. for causing the operation oifsaid -first named switching apparatus.

- 2. A telephone exchange system comprising a trunk circuit terminating at its outgoing end in a plurality of sets of switching terminals, a connecting circuit, switching apparatus associated with the trunk circuit having selective positions corresponding in number to said sets of switching terminals, means operative upon the connection of said connecting circuit with a set of switching terminals for controlling said switching apparatus, a plurality of pilot lamps corresponding in number to said sets of switching terminals, switching apparatus associated with the incoming end of said trunk circuit and operative in accordance with the setting of said first named switching apparatus 'for operating one of said pilot lamps and means at the incoming end of said trunk circuit for causing the operation of said first named switching apparatus.

3. A telephone exchange system comprising a trunk circuit terminating at its out- I going end in a plurality of sets of switching terminals, a connecting circuit, switching apparatus associated with the trunk circuit having selective positions corresponding in number to said sets of switching terminals, means operative upon the connection of said connecting circuit with a set of switching terminals for controlling said switching apparatus, a cord circuit for connection with the incoming end of said trunk circuit, a plurality of signaling devices and switching apparatus associated with said cord circuit and operative in accordance with said first named switching apparatus for operating one of said signaling devices.

4. A telephone exchange system comprising a trunk circuit terminating at its outgoing end in a plurality of sets of switching terminals a connecting circuit, switching apparatus associated with the trunk circuit having selective positions corresponding in number to said sets of switching terminals, means operative upon the connection of said connecting circuit with a set of switching terminals for controlling said switching apparatus, a cord circuit for connection with the in-coming end of said trunk circuit, a plurality of pilot lamps corresponding in number to said sets of switching terminals and switching apparatus associated with said cord circuit and operative in accord ance with said first named switching apparatus for operating one of said pilot amps.

5. A telephone exchange system comprising a trunk circuit terminating at its outgoing end in a plurality of sets of switching terminals, a connecting circuit, a step-bystep selective switch associated with the outgoing end of said trunk circuit having selective positions corresponding in number to said sets of switching terminals, means operative upon the connection of said conneeasee necting circuit with a set of switching terminals for controlling said selective switch, a cord circuit for connection with the incoming end of said trunk circuit, a plurality of signaling devices corresponding in number to said sets of switching terminals and a step-by-step selector switch operative in accordance with said first named switch for operating one of said devices, said devices and said latter switch being associated with said cord circuit.

6. A telephone exchange system comprising a trunk circuit terminating at its outgoing end in a plurality of sets of switching terminals, a connecting circuit, a step-bystep selective switch associated with the outgoing end of said trunk circuit having selec- Y tive positions corresponding in number to said sets of switching terminals, means operative upon the connection of said connecting circuit with a set of switching terminals for controlling said selective switch, a plurality of cord circuits for connection with the in-coming end of said trunk circuit, a plurality of signaling devices corresponding in number to said sets of switching terminals and a step-by-step selective switch operative in accordance with the said first named switch for operating one of said devices, said devices and said second named switch being common to said plurality of cord circuits.

7. A telephone exchange system comprising a trunk circuit terminating at'its outgoing end in a plurality of sets of switching terminals, a connecting circuit, a step by-step selective switch associated with the out-going end of said trunk circuit having selective positions corresponding in number to said sets of switching terminals, means operative upon the connection of said connecting circuit with a set of switching terminals for controlling said selective switch, a plurality of cord circuits for connection with the in-coming end of said trunk circuit, a plurality of signaling devices corresponding in number to said sets of switching terminals'and common to said cord circuits, a plurality of responsive devices associated with each cord circuit for operating said signaling devices and a step-by-step selective switch common to said cord circuits and operative in accordance with the said first named switch for operating one of said responsive devices.

8. A telephone exchange system comprising a trunk circuit terminating at its out-going end in a plurality of sets of switching terminals, a connecting circuit, a step-bystep selective switch associated with the outgoing end of said trunk circuit having selective positions corresponding in number to said sets of switching terminals, means operative upon the connection of said connecting circuit with a set of switching terminals for controlling said selective switch, a plurality of cord circuits for connection with the incoming end of said trunk circuit, a plurality of signaling devices corresponding in number to said sets of switching terminals and common to said cord circuits, a group of locking relays associated with each cord circuit for operating said signaling devices and a step-by-step selective switch common to said cord circuit and operative in accordance with said first named switch for operating one of such relays.

9. A telephone exchange system comprising a trunk circuit terminating at its outgoing end in a plurality of sets of switching terminals, a connecting circuit terminating in a selector switch, means for causing such selector switch to connect with a particular set of said switching terminals, switching apparatus associated with the out-going end of said trunk circuit having selective positions corresponding to said sets of switching terminals, means operative upon the con-' nection of said connecting circuit with a set of switching terminals for controlling said switching apparatus, a cord circuit for connection with the in-coming end of said trunk circuit, and a plurality of signaling devices and switching apparatus associated with said cord circuit and operative in accordance with the said first named switching apparatus for operating one of said signaling devices.

10. A plurality of classes of telephone lines, a trunk circuit, means for connecting any one of said lines to one end of said trunk circuit, signaling means, and a stepby-step automatic switch responsive to the seizure of the other end of said trunk for op erating said signaling means to indicate the class of telephone line associated therewith.

11. A plurality of classes of telephone lines, a trunk circuit, means for connecting any one of said lines to one end of said trunk circuit, signaling means for each of said classes of lines, a cord circuit for connection with the other end of said trunk circuit, and a selective switch in said cord circuit responsive to the connection of said trunk circuit with said cord circuit for operating said signaling means to indicate the class of telephone line associated with said trunk circuit.

12. A plurality of classes of telephone lines, means for similarly supplying said lines with operating current, a trunk circuit, means for connecting any one of said lines to one end of said trunk circuit, signaling means for each of said classes of lines, a.

step-by-step switch, and means responsive to the seizure of the other end of said trunk circuit for operating said step-by-step switch to actuate said signaling means to indicate the class of telephone line associated with said trunk.

13. In a telephone system, a plurality of lines of difierent classes, signaling means for each of said classes of lines, a trunk line, a connecting means at one end of said trunk line for each class of lines, two automatic switches, one for each end of said trunk line, and means for moving said two switches to actuate a signal corresponding to the class of the line connected. 1

14. In a telephone system, a plurality of lines of different classes, signaling means for each of said classes of lines, a trunk line,

means for connecting any one of the lines of said classes to said trunk line, a cord circuit, two automatic switches, one for said trunk line and one for said cord circuit, and means for moving said two switches to actuate a signal corresponding to the class of the line connected, operative when said cord circuit is connected to said trunk line.

In testimony whereof, I have signed my name to this specification this 15th day of 7 December 1920. I

JOHN F. TOOMEY.