US1846262A

US1846262A - Telephone system

Info

Publication number: US1846262A
Application number: US538303A
Authority: US
Inventors: Linus E Kittredge
Original assignee: American Telephone and Telegraph Co Inc
Current assignee: AT&T Corp
Priority date: 1931-05-18
Filing date: 1931-05-18
Publication date: 1932-02-23
Anticipated expiration: 1949-02-23

Description

Feb. 23, 1932.

L. E. KITTREDG E TELEPHONE SYSTEM Filed May 18, 1951 9 Sheets-Sheet l R m M W LEKITTREDGE ATTORNEY Feb. 23, 1932. Kn-TREDGE 1,846,262

TELEPHQNE SYSTEM Filed May 18, 1931 9 Sheets-Sheet 2 FIG. 2

IN VEN TOR LEK/TTREDGE ATTORNEY Feb. 23, 1932.

L. E. KITTREDGE TELEPHONE SYSTEM Filed May 18, 1951 9 Sheets-Sheet 4 m mm INVENTOI? LE. K/TTREDGE A TTO/PNE Y Feb. 23, 1932.

L.. E. KITTREDGE TELEPHONE SYSTEM 9 Sheets-Sheet 7 Filed y 18, 1931- IN VE N OR A TTO/PNE) IILIIII iH lllIlllH HI llHlllll HI IHHHII LEK/TTREDGE MNN Feb. 23, 1932. L E. KITTREDGE TELEPHONE SYSTEM Filed May 18, 1931 9 sheets sheet 8 /NVENTOi-? L. E. K/TTREDQE A T TOR/V5 V Feb. 23, 1932. 1.. E. KITTREDGE TELEPHONE SYSTEM Filed May 18, 1931 9 Sheets-Sheet 9 53 B wkommw E mqokxmmqc VWHIIHII mal lNVENTO/P LEK/TTREDGE B) ATTOPNIFY iii) Patented Feb. 23, 1932 entree STATES PATENT ow-"ice LINUS E. KIT'IR-EZDGE, OF BROOKLYN, NEW YORK, ASSIGNOR T0 AMERICAN TELEPHONE AND TELEGRAPH COMPANY, A CORPORATION OF NEW YORK TELEPHONE SYSTEM Application filed. May 18, 1931. Serial No. 538,303.

This invention relates to telephone systems and more particularly to line number indicating devices used in such telephone systerns.

In telephone systems where automatic switches are employed in completing some portion of a telephone connection it becomes necessary, when a calling subscriber desires to obtain a toll connection, to directively set one or more automatic switches to extend his line to a toll operators position and to provide thereat some means for indicating the designation of the calling line so that the toll operator may check the number of the calling line as given by the subscriber in order to properly assess the charge for the toll connection to the calling station.

i-lit the present time, this number checking, as it is called, is accomplished in divers ways, among which there are, for example, the well known checking multiple method; the method by which the operator, after having been given the number by the subscriber, sets a train of switches to select the calling line and thereafter lIHpIBSSBS a tone over one of the line conductors, the tone circuit being closed over the parallel extension set up by the operator and returning by way of the switches set by the subscriber to the operators position, so that, it the number of the calling station, as given by the subscriber, checks with the line terminals to which the operator has set the switches, the operator will hear the tone which was impressed over the line; and other methods for causing a lamp display of the calling line number, the lamp display circuit being set by trains of impulses characteristic of the calling line.

These and other means have been used with varying degrees oi success but either require the ()lihiit'tOl to obtain the line designation fromthe calling subscriber thereby slowing down the service or involving a large amount oi equipment o maintain. The object of the rarer-rent invention is, therefore, to provide means whereby, in response to a. calling subiber h extended the connection to an operators position, the operator thereat can, by the simple operation of inserting an answering cord into the jack of the extended connection and the operation of a key, receive an announcement of the calling line number, thereby supplying the operating company with a simple and eificient means for directly receiving calling line designations without the necessity of requesting the same from the calling subscriber.

In accordance with the invention, therefore, one specific embodiment of which is disclosed herein by Way of illustration, this is accomplished in the following improved manner: A hunting circuit is provided which comprises a group of selectors, each of the terminals of one of whose hunting arcs is multipled to a sleeve conductor of each of the subscribers lines in the ofiice. Two other arcs of each selector are used for the line number designation and the terminals of these arcs-correspondingto the terminal to which the sleeve conductor of the lineis eX- tended, are connected to a group of relays throughwhose contacts an organization of circuits is controlled which operates a call announcer in accordance with the terminal of the line on which the hunting switch is set.

The line announcer apparatus consists essentially of a phonographic machine constantly rotating and equipped with ten announcing drums and one timing drum, each of the, announcing drums having a phonegraphic record of one of the ten digits.

In general, my invention functions in the following manner: When a line has been extended by the subscriber to an operators position and the operator has received from the subscriber the office and number to which the call is to be completed, a knowledge of the number of the calling line is necessary so that toll charges will be correctly assessed therefor. In order to accomplish this, a key is depressed. The operation of this key impresses an alternating current potential on the sleeve conductor oil? the extended line and also causes other circuits to be closed for starting the hunting circuit to select the calling line. The alternating current potential on the sleeve conductor marks the calling line for guiding the hunting circuit to the terminals of said line. When the line to the sleeve conductorof which the alternating current potential has been impressed is reached, the hunting circuit stops and other circuits are thereafter closed over the corresponding terminals and brushes of two separate arcs of the hunting switch for operating two relays in a control circuit, the first of which serves to give the thousands and hundreds designation, and the second tens and units designation of the calling line. These relays, in operating, serve to start the line announcer circuit which, at the proper time, closes the circuits of various phonographic records of the numerals comprising, in succession, the calling line number, and the corresponding voice on rents are transmitted to the operators telephonecircuit. 'An announcement of the number is repeated at predetermined intervals, so that if the operator does not hear correctly the first time, she may listen as often as it is necessary tobe satisfied that the calling line announcement has been correctly understood. Thereafter, the key is released, causing the hunting circuit to restore to normal and the line announcer circuit to be disconnected from the hunting circuit.

While the invention herein described is disclosed with reference to well known panel telephone systems, it is to be understood that it is not so limited and may be readily applied by those familiar with the art to any telephone system.

A clearer conception of the scope and purpose of the invention maybe obtained by a consideration of the following description and attached drawings in which, V

igure 1 shows one of a group of subscribers lines togetherwith the line and the trip circuit common to the group of lines which serves to control a start circuit;

2 shows the start circuit serving a plurality of groups of lines;

Fig; 3 shows a line-finder district selector circuit for extending the line to subsequent selectors and other types of outgoing trunks, such as a trunk to the recording operators position;

Fig. 1 shows one of a plurality of link circuits serving the start circuit of Fig. 2 and having access to a plurality of line-finder district selector circuits such as shown in Fig. 3. A portion of two other links are shown;

Fig. 5 shows such parts of thecircuits of the sender disclosed in Patent 1,589,402 granted to O. H. Kopp and dated June 22, 1926, as is necessary for an understanding of the present invention, wherein the designation of the apparatus in Fig. 5 is identical with that of the same apparatus in the sender of the above mentioned patent;

Fig. 6 shows the calling line hunting circuit;

Fig. 7 shows the line announcing mechanism and control circuit;

Fig. 8 shows the trunk extending from the district selector frame to the recording position;

Fig. 9 shows the toll cord and cooperating operators telephone circuit, schematically shown, at such position; and

Fig. 10 shows the manner in which the above mentioned drawings should be arranged with respect to each other in order to disclose the invention completely.

WVhen'th e subscriber at substation 100 removes his receiver from the switchhoolr' a. circuit is closed for line relay 101 extending from battery through that relay, inner contact of relay 102 over the subscribers loop to ground at the outer contact of relay 102. Relay 101 operates and closes a circuit from battery, resistance 10 1, through the-winding of relay 103 to ground at the outer contact of relay 101. V

The operation of relay 103 closes a circuit from battery, resistanec 105.110 ground at the outer right contact of relay 103. This circuit is in shunt of'the winding of relay 106, which relay serves the second subgroup of the group to which line 100 belongs; thus preventing the extension of a call from that subgroup, while the trip circuit is in use with line 100. The operation of relay 103 also closes a circuit from battery, through the winding of relay 200, conductor133, outer left contact of relay 107, outermost left contact of relay 103' to ground. In addition, relay 103 closes a circuit from battery, over the back contact of relay 201, conductor 130, right winding of trip relay 108, inner left contact of relay 107, innermost left contact of relay 103, left contact of relay 109 to ground.

Relay 108 operates in this circuit and closes a locking circuit for itself from ground, right contact of relay 109, left winding and inner left contact of relay 108, over the inner left back Contact of the trip relays of the other groups of lines, conductor 129, right .winding of start relay 201 to battery. Relay 201 operates in this circuit. A circuit is now closed for relay 110 extending from battery through the winding of relay 110, right inner contact of relay 108, conductor 128, to ground at the outer right contact of relay 201. Relay 110 locks in an obvious circuit to ground at the left back contact of relay 109. Relay 108, together with relay 103, prepares a circuit from ground on the outer contact of relay 110, outer left front contact of relay 108, inner right contact of relay 103, conductor 131, left back contact of relay 202, outer left back contact of relay 203, conductor 206, upper contact of cam 101, upper contact of cam 102, brush 461 and its associated terminal, conductor 378, upper contacts of cam 301, winding of relay 302 to battery, assuming that the line finder of Fig. 3 had been a llotted for use by the switch 460 and the sequence switch 300 is therefore standing in position The operation of relay 108 also closes a circuit from ground over its outer right contact through the winding of the trip magnet 303 servin the group of lines in which line 100 apps on the line finder frame, to batte y. Relay 110, upon energizing, closes a circm from battery, through the left winding of relay 100. left n milling of relay 107, outer contact of ra ay 110 to ground. Relay 107 operates and locks throughits right winding and inner right contact, conductor 132, to the contact relay 200.

The operation of relay 302 closes a circuit from battery, through the winding of up drirc magnet 3 4, middle left contact of relay 302, upper 1 ft contact of cam 364, right L front contact oi. relay 302 to ground. Under the control of the updrive magnet 304 the line tinder shaft is moved UPWQHlS. Due to the operation of the trip magnet 303 the set of lu'iiishes serving the group of lines to which line 100 belon s is tripped. lVhen the shaft leaves the tripping zone a circuit is closed from ground o cr brush 307, through con1- niutator segment 305, upper contacts of cam 306, outer left normal contact of key 204, inner right contact and right winding of relay 201 to battery. Relay 201 is held operated in this circuit but the circuit through the lockinn winding of relay 108 is shunted and that relay releases, in turn releasing the trip magnet 303. As soon brush 307 leaves segment 305 the circuit of relay 201 is opened and that relay releases, again connecting battery to the opcrah. windings of relay 108 and the corrcspondng in other trip circuits, so that subsequent calls may be served.

l-lclay 302 closes a locking circuit for itself over its inner left contact, right contact of cum 308, back contact of relay 320, commutator segment ,brush 322 to ground, which is closed as soon as the line finder shaft moves upward. 302, also closes a circuil in battery, over the inner left contact of relay 205. right winding of relay 203, conductor 207, left contacts of cam 403, brush 402 a d its associated terminal, conductor 370, upper left contact of cam 311, right front contact of relay 302 to ground. The operation of relay 203 removes ground from conductor 206 thus preventing the starting of another line finder for some subsequent call until the brushes are tripped. Relay 203 looks in a circuit from battery, overthe outer left c tact of relay 20:), left winding and outer l front contact of relay 203, left back con tact of relay 202, conductor 131, inner right cont t of rel "y 103, outer left contact of relay 103, outer contact of relay 110 to ground. The operation of relay 203 also closes a locking circuit for relay 201 from battery, left contact and left winding of relay 201, inner right contact of clay .203 to ground. The circuits "just traced are established before relay 108 is released by the shunting action of commutator segment 305. As soon, however, as relay 108 deenergizes it opens the locking circuit of relay 203, restoring the start circuit to a condition to serve subsequent calls.

When relay 302 operates it also closes a circuit from ground through its right front contact, upper left contact of cam 311, c0nductor 379, brush 462 and its associated contact, right contact of. cam 404, lower right contact of earn 405, right winding of relay 406, winding of relay 407, upper left contact of cam 408, upper right contact of cam 409, resistance 410 to battery.

Relays

406 and 407 operate; relay 406 closing a locking circuit for itself and relay 407 from battery, through resistance 410, upper right contact of cam 409, upper left contact of cam 408, winding of relay 407, right Winding of relay 406, contact of cam 411, contact of relay 406 to ground. Relay 407 closes a circuit from battery, through the winding of sequence switch magnet 400, upper contact of cam 412, contact of relay 407 to ground. Magnet 400 operates advancing the link circuit sequence switch to position 2. i

In position 2 ground is connected from the right contact of cam 415 to brush 466 and its associated contact, conductor 375, lower right contact of cam 312, lower right contact of cam 313, left winding of relay 314 to battery. Relay 314 operates, but performs no function until the calling line has been found. Ground from the front contact of relay 406 is also extended over the contact of cam 411, lower right contact of cam 405, upper right contact of cam 404, left contacts of cam 403, conductor 207, right winding of relay 203, inner left contact of relay 205 to battery, holding relay 203 operated until the link circuit is moved out of position 1. When the link circuit arrives in position 2 relays 406 and 407 release. The release of relay 407 completes a circuit from ground at its back contact, left contacts of cam 405, winding of magnet 487 to battery. Magnet 487 oper: ates and closes an obvious circuit for magnet 488. Magnet 488 is the rotary magnet for sender selector switch 480 and causes the switch to rotate in search of an idle sender.

An idle sender is characterized by the connection of battery through a suitable re- 'sistance, such as resistance 501, to conductor tery is connected, relay 406 operates, .short circuiting its left hand winding over its con tact and the contact of cam 411, permitting relay 407 to operate in series with the right hand winding of relay 406. The operation of relay 407 opens the circuit of magnet 487 and closes a circuit from battery through the winding of sequence switch magnet 400, upper contact of cam 412, front contact of relay 407 to ground, advancing the link sequence switch toposition 3.

In position 3 a circuit is prepared extending from ground through the right and middle windings of relay 503, left contacts of relay 504, right outer back contact of relay 505, conductor 506, brush 484 of sender selector 480, lower contacts of cam 408, brush 464 of district finder 460 to conductor 315, left contact of cam 316, left winding of relay 317 to battery, which circuit is not completed until the district sequence switch reaches position 3.

In the meantime the line finder shaft con tinues to move upwards until it reaches the terminal corresponding to the calling subscribers line. lVhen these terminals are encountered a circuit is completed from battery, through the right winding of relay 109 in parallel with resistance 111, inner front contact of line relay 101, conductor 114-,terminal 380, brush 381, right contact of cam 318, wind ing of relay 320 to ground; Relay 320 operates and closes a circuit in shunt of its winding through resistance 319, right front contact of relay 320, commutator segment 321, brush 322 to ground. Relay 109, which is marginal, is so adjusted as not to operate in the circuit previously traced in series with relay 107 or in the circuit traced through the winding of relay 320. WVith resistance 319 in parallel with relay 320, however, relay 109 does operate. The operation of relay 109 opens the locking circuit of relay 110 and relay 110 releases after an interval due to the fact that relay 110 is slow to release.

Relay 320 opens the locking circuit of relay 302 and that relay releases as soon as brush 310 encounters an insulating segment on centering commutator 309. The release of relay 302 opens the circuit of updrive magnet 304 and stops the line finder on the calling subscribers line. It also connects battery through resistance 323 and its left back contact, lower right and upper left contacts of cam 324, right-inner back contact of relay 317, resistance 325, brush 326 and terminal 327, over conductor 112, windings of cut-off relay 102 to ground. Relay 102 operates and releases line relay 101 thereby removing the calling condition from terminal 380. The release of relay 101 opens the circuit through the right winding of relay 109 permitting its release as soon as relay 110 releases. The release of relay 101 permits relay 103 to release and also opens the circuit of relay 320. The connection of battery with terminal 327 marks terminal 113 and the other multipled terminals of calling line 100 in the terminal banks of final selectors with reduced battery potential to render the line busy at such final selectors. The release of relay 302 closes a circuit from battery through the winding of sequence switch magnet 300, lower left contact of cam 328, outer right front contact of relay 314, right back contact of relay 302 to ground. Sequence switch 300 is advanced in this circuit to position 3. I

When sequence switch 300 leaves position 2 the circuit of relay 314 is opened and that relay releases. When the sequence switch'300 reaches position 3, the previously traced circuit for relays 503 and 317 is completed. Relay 317, being marginal, does not operate at thistime. Relay 503 operates and closes an obvious circuit for relay 507 which, in turn, closes a circuit from battery, through resistance 508, winding of relay 509, outer left front contact of relay 507 to ground. Relay 509 operates and looks over its inner right front contact. Relay 507 closes a circuit for relay 510 from battery, winding of relay 510, conductor 534, to ground, at the inner left front contact of relay 507. The operation of relay 510 closes an obvious circuit for relay 511 which, in turn, closes an obvious circuit through the right winding of relay 512.

The operation of relay 512 opens the circuit previously traced from battery, through resistance 501, to

relays

406 and 407 and these relays release. The release of relay 407 closes a circuit from battery, through the winding of sequence switch magnet 400, lower right contact of cam 412, back contact of relay 407 to ground. Sequence switch 400 is advanced to position '4 from which position it is moved to position 5 by means of ground over the lower left contact of cam 412.

In position 5 of the link sequence switch the dialingleads are out through directly from the district selector to the sender circuit. The dialing circuit may be traced from battery, through the left winding of relay 606,Fig.. 5,:conductor 637, right normally made contacts of relay 513, sender selector brush 485, and its corresponding terminal, lower contacts of ca1n414, district finder brush 465 and its corresponding terminal, conductor 382, lower contact and cam 329, bottom inner back contact of relay 387, winding of relay 330, right back contact of relay 317, line finder brush 331, terminal 332, conductor 116 through the subscribers substation, conductor 117, terminal 333, brush 334,

middle left back contact of relay 317, top outer back contact'of relay 387, left contact of cam 335, conductor 375, brush 466 and its associated terminal, lower left contact of cam 415, brush 486 and its associated terminal,

outer right back contact of relay 513, to ground. WVhen the dialing circuit 1 above traced is completed, relay 606 operates and closes a circuit from battery, through the winding of relay 610, front contact of relay 606, conductor 639, inner right back contact of relay to ground. Relay 610 operates and closes a circuit from battery, through the winding of relay 609, right front contacts of relay 010, conductor 638, upper left contact of cam 516 to ground. As soon as relay 600 operates the dialing tone circuit is com pleted as follows: from source of tone 607, right winding of relay 606, normal terminal and brush 804 of register steering switch 800, Fig. 5, outermost left contact of relay 609, lower contact of cam 514, to groundat the inner left front contacts of relay 507.

Due to the closure of this circuit a tone is induced in the left winding of relay 606, Fig. 5 and over the dialing circuit to the receiver of the subscribers telephone to indicate that dialing may be started. The subscriber now dials the assigned long distance code number as the first step in extending his connection to the proper operators position from which position the connection is then further extend ed to the wanted long distance subscriber.

The operation of the sender in response to the manipulation of the subscribers dial and the consequent operation of the sender in causing the district selector to hunt for and connect with an idle trunk to the operators position are no part of the present invention, are completely described in the above identified patent to Kopp, and hence are not included as a part of this description; but, reference is made to that patent for a complete description of its operation.

l l hen, in accordance with the operation described in the above patent, the district selector has connected with an idle trunk eX- tending to the operators position regardless of whether such a position is in the same office or in another otlice, the district switch is advanced to position 10 and a trunk closure test made of the trunk from the sender. The circu t for this test extends from ground, ballast lamp 831, lower winding of relay 842, top outer back contacts of relay 803, lower left winding of repeating coil 813, conductor 834, bottom outer back contacts of relay 835. conductor 585 and cooperating terminal, lirush 855, left upper and right lower contacts of cam 356, conductor 379, brush 4.62 and cooperating terminal, right upper and lower contacts of cam 404, brush 482 and cooperating terminal, right front contacts of relay 507, outer back contacts of relay 524, compensating resistance 850, brush 832 of translator 830, lower contact of 021110525, left winding of rela 704, winding of relay 716, lower contacts of cam 717, outer back contacts of relay 711, right contact of cam 954, left contact of cam 523, right outer back contacts of relay 504, brush 481 and cooperating terminal, left lower and right upper contacts of earn 402, brush 461 and cooperating terminal, conductor 37 8, left inner back contacts of relay 359, upper contacts of cam 358, brush 357, conductor 386 and cooperating terminal, upper back contacts of relay 835, left upper winding of repeating coil 813, top inner back contacts of relay 803,upper winding of relay 842, ballast lamp 843 to battery. Relay 716 operates in this circuit but relays 842 and 704 do not. The operation of relay 716 functions to advance the sender to make the proper talking selection in the district, advance it to position 15 and thereafter to dismiss the sender, all in accord ance with the manner disclosed in the above mentioned patent.

lVith thedistrict selector in position 15 a circuit is closed over the above traced battery and ground path in the operators trunk circuit to

brushes

357 and 355, respectively, left contacts of cam 358, upper right Winding of repeating coil 360, lower contacts of cam 348, winding of relay 361, lower right winding of repeating coil 360, upper contacts of cam356, brush 355and thence through the above traced circuit at the o erators position, including relay 842. The resistance of this circuit is such that the quantity of current flowing through it is sufficient to operate relay 842, but its direction is opposite to that necessary to operate relay 361. Relay 842 operates and closes a circuit for relay 807 from ground on the contacts of relay 842, bottom normally made contacts of relay 808,'winding of relay 807 to battery. Relay 807 operates relay 805 over an obviouscircuit and relay 805 operates relay 806.. Relay 805, over its bottom front contacts, connects ground through coil 809 to conductor 883 and cooperating terminal in order to hold the district selector under conditions more particularly noted hereinafter. Relay 806, in operating, operates relay 810. Relay 810 closes a circuit from battery through the upper Winding of relay 811, upper winding of relay 812, top contacts of relay 810, top inner front contacts of relay 807, right upper winding of repeating coil 813, conductor 814, top back contacts of relay 815, upper left winding of re seating coil 816, top inner back contacts of relay 817, both windings in series of polarized relay 818, bot tom back contacts of relay 817, left lower winding of repeating coil 816, bottom back contacts of relay 815, conductor 819, right lower winding of repeatingcoil 813,.b0ttom inner front contacts of relay 807, bottom contacts of relay 810, lower windingof relay 812, lower winding of relay 811 to ground. Relay 818 operates in the circuit just traced, but relay 812 does not operate because the resistance of the circuit is too high, and polarized relay 811 does not operate because the windings are differential for the quantity of current flowing through the circuit. Relay 818 causes the operation of relay 820 over an obvious circuit, and opens, at its back contact-s, the lower winding of relay 821. The operation of relay 820 closes a circuit from battery on the top inner back contacts of relay 823, bottom outer contacts of relay 820, lamp 822 to ground. Lamp 822 lights as an indication that a call is awaiting on the trunk.

When the toll operator answers by inserting the plug of a toll cord circuit, such as shown in Fig. 9, into the trunk answering jack 824, a circuit is closed from battery through the upper winding of relay 900, top contacts of key 907, conductor 901, sleeve of cord and jack, conductor 825, lower winding of relay 826, upper winding of relay 821 to ground.

Relays

821 and 826 operate in the above circuit. Relay 821 causes the operation of relay 823 over an obvious circuit and opens the circuit of lamp 822 thereby extinguishing it. Relay 823 by closing its top outer contacts connects the left lower winding of repeating coil 816, through condenser 828 and thence to the left upper winding of the said repeating coil, and short circuits, through its relay 812 operates. Relay 812. in turn, causes the operation of relay 829. Relay 829 causes the operation of relay 803 over a circuit from ground on the top contacts of relay 829, bottom inner normally made contacts of relay 803, winding of relay 803 to battery. Relay 803 in operating, looks over its bottom inner make contacts to groundon the bottom contacts of relay 806, reverses the direction of current fiow'in the trunk circuit path above traced and including relay 361 in the district selector. The current fiowis now in the proper direction to operate relay 361, which, on operating, closesv a circuit for relay 314 from ground on the left contacts of cam 350,

front contacts ofrelay 361, left lower and right upper contacts of cam 34?, right wind-f ing of relay 314 to battery. Relay 314 operates and closes a circuit from ground on cam 339 and left lower contact thereof,right outer front contacts of relay 314, left lower contact and cam 328, winding of switch magnet 300 to battery. The switch magnet operates and advances the sequence switch to position 16 which is the talking to operator position, and in which position the district selector repeating coil 360 is removed from the trunk 'loop' and talking battery is supplied to the calling subscriber from battery through the ballast lamp 843, upper winding of relay 842, thence as traced to the upper right contact of cam 329, thence as tracedover the calling line loop to cam 335 and the upper contact thereof thence as traced through the lower winding of relay 842lto ground. Relay 842 now holds over the said loop. In position 16, relay 314 is held locked over a circuit from ground on the bottom front contacts of relay 805, through coil 809 to conductor 383 and cooperating terminal as previously described, brush 349, right contacts of cam 350, right inner front contacts of relay'314, left winding of relay 314 to battery. The operation of relay 803 also completes, over its bottom outer contacts, the talking circuit by connecting condenser 844 to the two right windings of repeating coil 813.

It will be noted that the trunk circuit above described and connecting the district selector with the operators-position isone of a well known type which is used when the operators position is located at adistance from the originating central oflice and in which but two trunk conductors, namely, 814 and 819, extend from the said office to the said position. Consequently, the method of signaling the outgoing end of the trunk from the said position to connect an alternating potential to the sleeve conductor: of the connection as de scribed hereinafter is one specifically adapted to the type of trunk'herein used to illustrate the invention. 7 However, it is understood that the invention is not limited to any particular kind of trunk as it is realized that the connection between the first switching stage and the operators position may be accomplished in a variety of ways, all of which would be satisfactory foruse with the present invention provided that the trunk contains facilities, or can be modified to contain facilities,

which are responsive to an operation at the ated. Key 907 disconnects the cord sleeve circuit from that of the trunk and substitutes battery therefor'through high resistance 908.

Relays

821 and 826 release; relay 821 momentarily, due to the switching of the circuit at the contacts of key 907 and relay 826 due to the decrease in current. Relay 823, however, does not momentarily release in consequence of the release of relay 821 due, to its slow to release characteristic. Re lay 821 reoperates when the key connects resistance 908 to the sleeve circuit; The release of relay 826 removes the shunt around the winding of relay 817 and this relay now operates in a circuit from battery through the top inner front "contacts ofrelay' 823, resistance 839, winding of relay 817 to ground. The operation of relay 817v disconnects the windings of relay 818 from the trunk conductors causing it to release. Relay 820,-however, doesnot release by the release of relay 818 since it is slow releasing, and is subserpicntly locked in a circuit over its top outer contacts to ground on the top outer contacts of relay 817. The operation of relay 817 connects a. battery of a hi 'her voltage to the trunk conductors over a path from battery th rot ;"h the upper Winding of retard coil 8 ft), bottom inner front contacts of relay 820, bottom front contacts of relay 817, left lower "win lii gof repeating coil 816, conductor 833, bottom back contacts of relay 815, conductor till), ri ht bottom winding of repeating coil 813, bottom inner front contact of relay 80?, bottom contacts of relay 810, bottom winding of relay 812, bottom winding of relay 811 to ground. .iinother circuit also exists from groinid through the bottom Winding of re tard coil 840, top inner front contacts of relay 820, top inner front contacts of relay Fill, left upper winding of repeating coil 816, conductor 82?, top back contacts of relay filth, conductor en, right upper winding of repeating coil 813, top inner front contacts of relay 807, top contacts of relay 810, top winding of relay 812, top winding of relay 811 to battery. Due to the difference in current flow between the circuit through the upper winding and that through the lower winding of relay 81]. caused by circuits of different battery potentials, the opposing characteristics of the windings of relay 811 are overcome and sufficient current now flows through the lower winding of relay 811 to overcome the effects of the opposing current through the upper winding so as to cause relay till to operate. Relay 811, in turn, causes the operation of relay 808. The operation of relay 808 closes a circuit from ground through the secondary Winding of a. runs-dormer 8-721 connected to a source of alternating current, top outer contacts of relay R08, sleeve conductor 383 and cooperating terminal, brush 349, right contacts of care 350, right inner front contacts of relay 314,

5 contacts of relay 31 i, right upper and lower contacts of cam 348, condenser 888, contacts of cam 389, winding of relay 390 to ground. Relay 390 operates and closes a circuit for relay 387 from ground on the contacts of relay 390, top winding of relay 387, conductor 391, which is inparallel with the top winding of each relay 387 in each of the d rict selectors, to battery on the back contrcts of relay 6-17. Belay 387 operates in this circuit and connects the district selector connected to the calling line to the common calling line start circuit of Fig. 6. Relay 38? connects ground through its top inner conto conduct-or 392. This conductor is connected to one relay of a group of which relays $00, 601, 602 are representative and each relay of the said group is common to on c group of line finder-district selectors serving a group of subscribers on a line finder fii'ame; there being as many relays in the said group as there are groups of line finderdistrict selectors serving separate groups of subscribers. In accordance with the manner in which subscribers lines are arranged and distributed shown in the above identified patent to Kopp, there is a group of line finder-district selectors to each line finder frame. There is, however, but one common calling line test circuit for the whole oiiice in the present embodiment of my invention so that when a district selector is taken into use on which calling line verification is necessary, the common calling line test circuit must identify the line finder frame which holds the calling subscribers lineto the terminals of which the selected line finder end of the district selector is connected; This is accomplished, in the present embodiment of the invention, by connecting conductor 392 to the top middle contact of relay 387 of all district selectors having accessibility to the same line finder frame and connecting conductor 392 to a relay, such as relay 600 in the calling line test circuit which identifies :90

that frame;.there being as many conductors 392 in the oilice as there are separate line finder-district selector groups having accessibility to different line finder frame groups of subscribers.

lVhcn, therefore, conductor 392 is grounded as before described, the associated line finder f'anic identifying ly 600 is operated over a circuit from ground on conductor 392, normally made contacts of the right Ho. 1 Contact set of relay (500, right winding of relay 600, conductor 6&8, to battery on the back contacts of relay 603. Relay 600 operates, locks in a. circuit from battery through the left No. 1 front contacts and left winding of relay 600, right lie. 1 front contacts of relay 600, to ground on conductor B92. Relay 600 also connects battery through the winding of relay 647, conductor 6 h), right No. 3 contacts of rela G00, conductor 39%,

bottom middle front contacts and lower winding of relay 887. to ground on the contacts of relay Relay 387 locirs in the above circuit while relay 6-17 operates and removes operating battery from the top wind inc; of all relays -87 in the district selector. The bottom middle back contact of relay 38'? of the districtselector shown in F 3 is connected to the bottom middle armature of relay 38'? of the next district selector. Every selector, th refore is connected to every other in a series preference chain connected to the winding of the battery supply relay 647. Hence when one district selector is connected to the common cal. 11g lino tee-t circuit, no other district selector in the office can, at the same time, become connected to it since, with the operation of relay (S t? in the locking circuitof relay 387 of thedistrict then associated with thetcst circuit, operating battery for all other relays 387 isremo'ved at the contacts of relay 647. This condition remains undisturbed until the calling line test circuit has identified the calling line as will more clearly appear hereinafter.

Relay 600 causes the operation of relay 604 over an obvious circuit. Relay 604 closes the circuits of all rotary selector magnets such as 655, 656, 657; there being as many selectors associated with a relay such as 604, foreX- ample, as are needed to accommodate on the contacts of their associated test arcs the sleeve conductors, such as 135, from all the subscribers lines terminating on the line finder frame or frames identified by relay 600 and hence by relay 604. There are other relays, like 646, which control separate groups of switches whose test arcs are wired to the sleeve conductors of subscribers lines terminating in another line finder frame or frames which are identified by relays such as 601 and 602. Only the complete circuit of one group is shown; other groupsbeing identical with the one disclosed. Relay 604 also connects, through its left contacts, test brush 611 of switch 661 to the winding of relay 614, test brush 617 of switch 662 to the winding of relay 616 and test brush 620 of switch 663 to'the winding of relay 615.

Meanwhile as soon as relay 600 operates, an alternating current circuit is closed fro-1n ground through the secondary winding of transformer 700, conductor 701, left No. 4 contacts of relay 600, conductor 395, bottom outer contacts of relay 387, top contacts of cam 368, brush 326, terminal 327, conductor 112 to sleeve terminals 113 and 134. Now the sleeve of each subscribers line is multipled to a contact on the arc of a switch such as switch 661, in the calling line test circuit. Consequently, in the case under consideration, terminal 134 is cross-connected to a similarly marked terminal 135 wired to a contact on the arc of switch 661 cooperating with test brush 611.

WVhen relay 604 operated, as already described, the operating circuits of the switch magnets 655, 656 and 657 were closed and these magnets operated to rotate their respective brushes over the three corresponding cooperating contact arcs. As soon as brush 611 makes contact with terminal marked 135, the aforetraced alternating current path to terminal 135 is completed over brush 611, left No. 5 contacts of relay 604,

winding of relay 614, condenser 623 to ground. Relay 614 operates and, over its right outer contacts, closes an obvious circuit for relay 642 which operates. On its right inner contacts, relay 614 opens the circuit of switch magnet 657 and relay 642 opens the circuit of switch magnets 656 and 657 causing the

switches

661, 662 and 663 to stop. The brushes 611, 612 and 613 of switch 661 are brought to rest on the contacts with which they. make, as is likewise the case with the brushes of switches 662 and663'. Relay 614, over itsleft outer contacts completes a circuit for relay 658 from ground on the left outer contacts of relay 614, left No. 2 contacts of relay 604, winding of relay 658, left inner contacts of relay 659 to battery on the left inner contacts of relay 660. Over its left inner contacts, relay 614 partially prepares a circuit for relay 702which may be traced as follows: ground through the winding of relay 702, conductor 70.3, left inner contacts of relay 614, conductor 728 to battery on the left contacts of relay 705 when this relay is operated as described hereinafter.

Relay 658 in operating, connects ground over its right contacts to the two brushes 612 and 613 which are on the same shaft as brush .611 and are in contact with terminals corresponding to terminal 135 of the arc cooperatingwith brush 611. At its left contacts relay 658 removes operating battery for

relays

659 and 660. 7

Now the terminals on the arcs cooperating with brushes 612 and 613 are cross-connected to cross-connecting rack 624 and, in accordance with the subscribers line number, to the appropriate identifying relays some of which are represented by relays 626 to 636, 664, 665, 666, 640 to 643. There are two groups of identifying relays: one group consists of one hundred relays to designate the thousands and hundreds digit of the line number, and are, for the sake of convenience, designated from 00499 and'are represented, in part, by relays 626 to 630, inclusive. Another group, likewise designated 00-99, identifies the tens and units digit of the line number and are represented in part by

relays

635, 636, 664, 665, 666, 640 to 643. The winding of each of these relays is connected to the cross-connecting rack 625 and the conductors from the switch banks cooperating with

brushes

612 and 613, or 618 and 619 or 621 and 622 and wired to rack 624 are then crossconnected to the appropriate relays of the two groups in accordance with the subscribers line numberas represented by any two of switches 661,662 and 663 and similar switches of other groups in the calling line test circuit. The terminals of the arc cooperating with brush 612, or those corresponding to it in other switches, have to dowith the first two digits of the number and corresponding terminals on the switch banks the contacts. of the are cooperating with i brush 613, or those corresponding to it in other switches, with the last two digits. Thus, for instance, if the line number is 9700, the conductor connected with the terminal on the are cooperating with brush 612 and come .sponding toconductor wired to terminal 135,

will be connected to relay 628through the cross-connecting racks 624625, which relay is the 97th relay of the group fordesignating the thousands. and hundreds digits. Terminal 00 of the terminal rack 624, on the other hand, is connected with the corresponding terminal on are cooperating with brush 61.3 and is also cross-connected to terminal 00 on rack 625 which, in turn, is connected to the winding of relay 643; this relay being the first 01 the group of one hundred relays designating the tens and units digit.

Referring back to the operation of the circuit, the fact that brushes 612 and 613 are in contact with terminals which are cross-connected to terminals wired to the windings of relays 628 and 643, respectively, causes both of these relays to operate from the aforetraced ground to the said brushes from the contacts of relay 658. The function. of these relays will be apparent from a consideration of the line announcing mechanism and controlling circuit given below.

The line announcing mechanism, shown in Fig. 7, illust'ates one form which such a mechanism may take. It comprises a series of drums having opaque and partially transparent sections, the partially transparent sections being photographic records of the sound corresponding to digits from zero to nine. The light from a source, such as lamp 729 may be directed by any suitable means through the speech record to a photoelectric cell, such as 718, connected to one side ofa transformer, such as 730. The output currents from the transformer are amplified through amplifier units, such as 0, and transmitted to the trunk line in the manner hereinafter described. The line announcing mechanism such as disclosed in Patent No. 1,645,57 3 patented October 18, 1927, in the name of H. M. Bascom may also be employed.

The line announcer connecting circuit slurwn in Fig. 7 also illustrates one manner in which the connection between the calling line announcing mechanism and the calling line identifying relays of Fig. 6 can be made. It comprises a plurality of multi-contact relays of a structure well known to the art, arranged in two separate groups. To the separate armatures of the relay of each of these groups is connected a conductor wired to the contact of some relay in one of the two groups oi" calling line identifying relays. To the armaturecontacts of multi-contact relay 712 are connected the conductors coming from the contacts of the group of relays 626--634 identi'lt'ving the thousands and hundreds digits, while to the armature contacts of relay 714 are connected the conductors coming from the contacts of: the group of relays 635, 636, 664. 665, 666, 640, to 643 identifying the tens and units digits.

Two other multi'contact relays, namely re- .iays 713 and 715 are also provided, each of those relays having 100 contact pairs divided into 16 groups of 10 pairs of contacts each. The arinatures of each group are strapped together and connected to one side of a particular amplifier. The mates of the contacts of all the 10 groups are connected to a group of comtothe said common conductors depends upon the particular amplifier to which the common armatures of any group are connected. 1 For example, one side of the amplifier 0 is connected, so far as multicontact relay 713 is concerned, to the armatures O to 9 of one group which are multipled together. \The contact making with armature 0 is cross-connected to conductor 00, the contact making with armature 1 is cross-connected to conductor 01 and so on with all, the contact making with armature 9 being cross-connected to conductor 09. In the same way, one side of the amplifier 1 is connected to the second group of armatures and their corresponding contacts are likewise connectedin the numerical order to conductors 10 to 19." In a like manner the remaining announcing drums are each connected to a group of 10 armatures of relay 713 and the corresponding contacts of each group are connectedto those common conductors the first digit of whose numerical designation is the same as the number of the amplifier, while the second corresponds to the number of the armatures. That is, the 100 common conductors, being designated 00 to 99, the amplifiers are'connected through relay 713 in such a manner that each drum is mnltipled to the 10 conducitors whose first numerical designation is the same as the number of the amplifier.

The contacts of relay 715 are likewise di tucked into 10 groups of 10 pairs of contacts each and one side of each amplifieris likewlse connected to aseparate group of 10 armatures. The contacts making withthese armatures, however, instead of being connected to the various ones of the 100 conductors in accordance with the identity of the first numerical digit of its designation with the numerical designation of the amplifier, are now connected in the order of the second digit of the numerical designation of the sa1d 100 conductors. That the contact making with armature 0 of the group of ar matures connected to ampIifierO is connected to conductorOO, the contact making with armature 1 of the same group is connected to conductor 10, the contact making with the armature 2 is connected to

conductor

2,0 and so on, the contact making with armature 9 being connected to conductor 90. In the same Way the contacts making with the group of armatures connected'to one sideof the amplifier 1 are connected to common conductors 01, 11, 21, 31, 41, 51, 61, 71, 81 and 91 and likewise all contacts making with the armatures of the remaining groups are connected to those common conductors whose last digits are identical with the numbers of the ampliloo matures isconnected.

fiers to which the cooperating group of ar The subscribers numerical designation in the oihce in which his line terminates is divided into two parts by the identifying relays in Fig. 6, the first part consisting of the thousands and hundreds and the second of tens and units as already described. One contact of each of the relays in the thousands-hundreds identifying group is carried to an armature of multi-contact relay 712 while the contact of each of the relays in the tens-units identifying group is each carried to an armature of multi-contact relay 714. The contacts of multi-contact relay 712 making with their respective armatures are each connected to the common conductor of like numerical designation asthe'identifying relay tothe contact of which is connected the cooperating armature. The armatures of relay 714 are likewise connected to the common conductors bearing a similar numerical designation as-the identifying relays to the contacts of which are connected the respective armaturesof relay 714. V V V The manner in which the line announcing mechanism as well as theconnecting circuit operate to give an oral pronouncement of the calling subscribers line will now be described- The time at which announcements are made corresponds with the period when the unshad ed segment of the-timing drum 719 is incontaet with brushes-720 or 721. As already explained, the circuit ofrelay 702 is not completed. until relay 705 is operated, which event occurs only during periods of no announcement- Assuming, therefore, that relay 7051is operated, the above traced circuit. of relay 702 iscompleted to battery on. the front contacts of relay 7 05.and relay 7 02 looks to battery on the front contact of relay 603.- Starting. from the instant when the unshaded'or commutating segment of the timing drum makes contact with brush 7 21 an obvious circuit isclosed for multi-contact relay 713, causingit to operate. Relay 713, at its. right contacts, closes a circuit for relay 731. from ground on the right contacts of relay 713, back contacts of relay 710, winding of relay 731. to battery. Relay 731 operatesand completes a circuit for relay 712 from ground on the back contacts of relays 707 and 709, left contacts of relay 731, winding of relay'712 to battery. Relay 7.12 operates and closes its contacts to connect with the contacts of the first group of identifying relays in Fig. 6.;

It was assumed hereinbefore that the calling subscribers line designation was 9700. Consequently relays 628 and 643' are energized in'the manner already described". The contact of relay 628 is connected to conductor 722 whicln'inturn, connects with the 97th armature of multi-contact relay 712, while the contact of relay 643' is connected to conductor 723- which connects with the first or :00 armaturev of multi contact relay 714. "When, therefore, multi-contact relays7l3 and 712 operate as above describedQa circuit isclosed from ground through the right winding of repeating coil 724, condenser 725, left contacts of relay 702, conductor 726, contacts of'relay 628, conductor 722, contact pair 97 of multi-contact relay 712 corresponding contacts of multi-contact relay 713, through amplifier 9-to battery. The circuit for they oral pronouncement of the numeral 9'is thus made and is repeated over the trunk of, the established connection to the recording operator. as follows battery through the ballastlamp 843, upper Winding of relay 842, top outer front contacts'of .relay803, left lower winding of repeating coil 813, bottom back contacts of relay 835, conductorv 385 and associated terminal, brush 355, right contact of cam 329,.bottom inner front contacts of relay 387, conductor 397,.left No. 3 contacts of relay 600, conductor. 645, left winding of repeating coil 724, conductor 644, left No. 2 contacts of relay 600, conductor 396,- top outer front contacts of relay387,-cam 335 and right upper contact thereof, brush 357, conductor 386' and associated terminal, top outer back contacts of relay 835, left upper winding of repeating coil 813, top inner front contacts of relay 803, bottom winding of relay 842,

ballast lamp 831 to ground. The oral pronouncement is'further repeated over the fol lowing closed'loop: OIIG SIdG of condenser 844, right upper winding .of repeating coil 813, conductor 814, top back contact of relay 815, conductor 827, left upper winding of repeating coil- 816, condenser 828, top outer contacts of relay 823, left lower winding of repeating'coil 816, conductor 833, bottom back contacts of relay 815, conductor 819, right lower winding of repeating coil 813, bottomouter contacts of relay 803 to other side of condenser 844. is repeated to the operators telephone circuit over the following pathz conductor 903 connecting with the operators telephone circuit, not shown, bottom contact of key 902, which is operated, bottom normal contacts of key905, bottom normal contacts of key 906, ring trunk conductor 836, right lower windin'g'ofrepeating coil 816, condenser 837, right upper winding of repeating coil 816. tip conductor 838, top inner normal contacts of key 906, top inner normal contacts of key 905, top inner make contacts of key 902, to conductor 904, connecting with the operators telephone circuit. The operator thus hears the oral pronouncement 9 for the thousands digit of the calling subscribers line designation,

The pronouncement is completed at the time brush 721 of the timing drum engages an insulating segment, at which time relay Finally the signal 713 releases. Relay? 10, which durin the announcement is held normal by the lllIlting ground from the. rightcontacts of relay 713 to one side of its winding, now operates in series with relay 731 and looks over the right contacts of relay 7 31 to ground on the right contacts of relay 705, this last relay having released meanwhile as explained hereinafter. hen the timing drum has rotated to the position in which the commutating segment engages brush 720 an obvious circuit is closed for inulti-contact relay 715. With the operation of this relay and relay 712 remainingienergized, a circuit is again closed over the previously traced path over conductor 720 to conductor 722 through the 97th pair of contacts on relay 712, the7th pair of contacts of the 7th group of armatures of re lay 715 connected to the No. 7 amplifier, through the No. 7 amplifier, to battery. The operator now hears the pronouncement of the second or hundredsdigit of the subscribers number, which, in the illustration assumed, is 7. The pronouncement is completed when the timing drum is rotated so that the commutator segment no longer engages brush 720 at which time relay 715 releases and dis connects the announcing drums from the contact-s of relay 715. When the timing drum rotates to where itscommutating segment engages brush 721, thepreviouscircuit is again closed for operating relay7 13 and the closure of the right contacts of this relay closes a circuit for relay 709 from ground on its right contacts, front contact of relay 710, back contacts of relay 708, windingof relay 709 to battery. Relay 709 operates in this circuit, opens the circuit of multi-contact relay 712 and closes the following circuit battel-y, winding of relay 714, left front contacts of relay 709, back contactsof relay 707 to ground. Relay 708, meanwhile, remains short circuited from, ground on one side of its winding through the back contacts of relay 705 and right front contacts of relay 709 and also by ground on the other side of its winding through the front contacts of relay 713, as already traced. Relay 713 connects the announcing amplifiers to the contacts of said relay and relay 714, in operating, likewise connects allof the conductors of which conductor 723 is one, from the second set of identifying relays in Fig. 6 to the armatures of multi-contactrelay 714. Remembering that the tens numerical designation of the calling subscribers line is Zero,'a circuit now closed over a previously traced path on conductor 726, contacts of relay 6 13, conduetor 723, the number 00 armature of relay 71 i, armature 0 of relay 713, number 0 amplifier, to battery. The operator now hears the pronouncement 0 which is thetens digit of the calling suhscribers number.

When the timing drum is disengaged from i brush 721, relay 713 disconnects the amplifiers all from the comnionconductors. The release of relay 713 also removes the short circuit around the winding of relay 708 so that this relay now operates and locks in series with relay 7 09 to. ground on the right contacts of relay 705. IRelay 714,. however, remains operated.

When'the timing drum commutator segment againengages brush 720, multi-contaot 715 again operates as already described and the amplifiers are again connectedto the common conductors and to the conductors connected with the second set of identifyingrelays and hence .1 to conductor. 723 through multi contact relay 714. i The circuit previously described over

conductors

726 and 723 is again closedto that) amplifier and the operator hears the oral? pronouncement 0 of the unitsdigit "of the calling subscribers number. When brush 720 is disengaged from the timing drum, relay7 15 releases, thereby disconnecting the amplifiers from the common conductors andhence from the conductors to the identifying relays. When the commutating surface of thewtiming drum makes with brush 721, relay 71.3 operates and over its right contacts, closes arcircuit for relay 707 from battery throughithe Winding of relay 707, front contacts of relay 708, front contacts of'relay710 to ground on the front contacts of relay713. Relay. 7 07 contacts 712 and 714, no announcementfis transmitted to the recording operator.- When the commutator segment disengages brush 721, relay. 713 releases. The shunt around relay 706 is thereby removed and relay 7.06 operates and locks in series-with the winding ofrelay 7 07 to ground on thejright contacts of relay 705by way of the front contacts of relay 707; Relay 706 closes an obvious circuit'for relay 705, which inloperating, unlocks relays 707, 706,709, 708, 731 and 710.

It is during this period of no announcement that relay 705 is operated and consequently furnishes battery for relay 702, in order to prevent a connection being set up to theoperators telephone circuit from the line announcer circuit in the midst of a pronouncement. l/Vhen 'relay706 releases, relay" 705 likewise releases and if, prior to its release,

ground. through relay"702 is still connected to conductor 728, relay 702 will reoperate and the above cycle of operationsis repeated thereby giving the operator another pronouncement cycle of the calling subscribers number. This proiiouncement is repeated for every cycle of operation described above, there being two pulsing intervals of the timing drum between each pronouncement;

After the operator has heard the announce-