US1504230A - Telephone-exchange system - Google Patents

Description

J. W. GOODERHAM TELEIHONE EXCHANGE SYSTEM Filed OCT.. 19 1921 3 Sheets-Sheen 1 www m? www J. W. GOODERHAM TELEPHQNE EXCHANGE SYSTEM Filed 0012-. 19, 1921 5 Sheets-Sheet 2 Aug.. 12, mm www@ J. VV. GOODERHAM TELEPHONE EXCHANGE SYSTEM Filed oct, 19. i921 3 sheets-sneer 3 Patented Ang.. l2, p llQZiln sirarf s laitttt JOHN W. @COREE-HAM, 03:" YGNKERS, NEEM YORK, ASSIG-NOR TO WESTERN ELECTRIC COMPANY, NCRPOBAATED, ,lll YORK, N. Y.,

CQRCBRATION OF NBVT YORK.

TELEPHONFI-EXCHANGE SYSTEK.

.Eipplication tiled *October 19, 1921. Serial No. 508,713..

To all whom t may concern:

Be it known that l, Toi-1N W. Goosen- HAM, a citizen of the United States, residing at Yonkers, in the county of Westchester, State of hl ew York, have invented certain new and useful improvements in Telephone-Exchange Systems, of which the following isV a full, clear, concise, and exact description.

This invention relates to telephone eX- change systems and particularly to an arrangement for making observations on the service afforded subscribers lines in the establishment of calls.

ln exchange systems where machine switching apparatus is employed at the central oliices for setting up connections, it is desirable to take observations, from time to time, to ascertain the manner in which the apparatus is functioning and to determine the quality of service being given the subscribers. Such information is not only of interest to the telephone company in showingu the performance of the automatic switchinp,` equipment, but also serves to delinitely ascertain whether complaints entered by the subscribers against the quality of the servire are due to failures in the apparatus or because of an improper usage by the subscriber of his telephone instrument, or for any other reason.

ln order that this information may be readily and convenientlyY obtained, a special desk is provided in the central office and equipped with apparatus and circuits for taking all the required oliiservations on subscribers lines. The observing operator presiding over the desir may insoect the op-` eration of all switching mechanism involved in the extension of an;7 larticular subscribers line responsive to the origination of a call thereon. The observing1 equipment is arranged to be associable with any suitable varia-ble number of lines at time and when thus allotted it serves to enable obsewations on any calling' line in such group. To avoid mistakes, which might arise by interference in the association of the equipment with lines calling; simultaneously, the arrangement is such that only one line of the group can be connected to said equipment at a time. When all notations have been taken with respect to a given line the observers apparatus is released and thereafter may again be connected to some other line in the group. From the nature of the tests made on a line, it is essential that the observing operators equipment be associated with the line from the beginning of the call.

An object of the present invention is, therefore, to insure that an operators position, when disconnected y from one subscribers line at a time subsequent to the initiation of a call on another line, cannot e connected to such other line.

Another object of the invention is to enable the taking of certain information at the operators position regarding the transmission of impulses over the line and to signal the operator whenever such impulses are improperly transmitted.

A feature of the invention relates to the provision of means, in an arrangement where the operators equipment is automatically connected t'o a line on the initiation of a call, for delaying' the connection of such equipment with another line following its disconnection from a given line until the time when no call exists on any of the lines.

'Other and further features contemplated by the invention will be considered in detail hereafter.

`liefr-irrinp` to the drawingr forming a part of this application, Figs. l, 2 and 3 when v' arranged with Fig'. 3 below Fig; l and 2 to the left of Fig. 3, illustrate a portion of an automatic telephone exchange to which the circuits and apparatus embodying the principles of the present invention are adapted.

Fig. l shows, in the upper portion thereof, a subscribers line incoming` to the centrai oifice from when it extends through the distributing): frames to an individual line switch. There is also diagrammatically illustrated a trunk leading from the line switch to a lirst or district selector, a register sender for controlling selections and a trunk outgoing from the district selector. ln the lower part of this figure a similar showing is given of a subscribers line incoming to the central office., with the exception that in this case line finder switches are used instead of individual line switches for exten-ding calling lines to the district switches. In Vboth modifications of the er.'itching` apparatus, as shown in Fig. l, there is further illust-rated an arrangement whereby connections may be made with subscribers lines for observation purposes by means ot plugs and j acks, the plug circuits being attachable. to the line conductors at the distributing` frames.

l? ig. 2 shows an observing operators position at which there is located the necesi sary devices 'for taking observations of the service on calling lines.

1n the space set ofi by the broken lines in the upper right-hand corner of Fig. 3, there are shown the several elementsV individuail. to one of the connecting circuits leading from the jacksk shown in Figi, 1 to the observing operators position. In the small rectangle to the leftthereofl are-shown a i'ew or the corresponding,elements individual to a vsecond one ot these connecting circuits. In the remaining. portion of the ligure, the circuits and relays common to all connecting circuits are illustrated, More# over, in addition to being applicable to the two classes otsystems above mentioned, both ot which involve central otiice controlled power driven switches, the observing apparatus is also applicable to systems ot the step-by-step character.

Although the invention is applicable to other types of systems, the present disclosure shows its adaptation to a full mecham al system. v Before describing the features of the operation ot the observing apparatus shown in Figs. 2 and 3, an explanation will tirst be given of the machine switching mechanism serving the subscribers lines on which the service observations are to be made. As was mentioned above, either individual line switches, such as line switch 128, or line nders, such as the finder 132, may be employed for extending the calling subscribers line through to a district selector switch. The district selector 180, shown in connection with a subscribers line served by an individual line switch and the similar district selector switch 134i shown in connection with lines served by line finders, may be. o't the power driven type in which the selection of brushes and thel movement thereof' into engagement with the desired outgoing circuits are accomplished by means oiA applying a constantly driven element to thel movable member of the switch. The structure and operation of switches ot' this general character are shown and described in detail in the patent to E. B. Craft and J. N. Reynolds, No. 1,128,696, issued January 5, 191.5. The selective movements otthe district switches .and also of succeeding switches in the establishment of the connection are controlled by ineansfoiA the revertive impulse register l senders diag-rammatically shown at 181 and- 1375. These senders are ot the usual-type used for controlling power driven switches'and 'receive the record from the calling subscribers dial which later serves to govern-- the directive movement of the switches. A register sender of the character suitable tor use in controlling the switches illustrated in the present system is described in detail in the Patent 1,395,977, issued to F. A. Stearu and F. J. Scudder, November 1, 1921.

The subscribers line A. which is one of a. plurality ot' lines terminating in the multiplel contacts oic the line linder 132 on entering the central otiice, is ti'rst directed to the main distributing frame. MDF. From here it leads to the terminal racks o'lffthe intermediate distributing iirame IDF.' Between the main and intermediate trames the subscribers line is directed through the heat coils 126 which act as a protection against heavy currents.V At the intermediate dis tributingtrame, the line is connected and distributed to the desired terminals iu the bank of the line finder switch. desired to make observations on the suhscribers line A, the heat coils 126 are removed and a spring connecting plug` 125 is inserted as shown. The plugA switch is the terminating end of a pair ot' cord circuits 1119, 150 and 147, 148. These connecting cords at their other ends terminate. respectively, in the plugs 122 and 123. A third connecting cord 156, 157 terminating in the plug 124 is connected to the proper "l terminals at the intermediate distributing trame by any suitable means such as a shoe 127. To complete the association of the line A with the observing position, the plugs 122, 123 and 124 are inserted, respectively in the jacks 119. 120 and 121 provided at` some convenient location in the vicinity ot thefdistributing trame. From the jacks 119. 120 and 121 the connecting circuit.v comprising conductors 102. 103, 1041-. 105, 100 and 107, leads to the individual apparatus shown in the upper right-hand corner ot Fig. 23. ln this manner the line A is connected through to the operators position and the individual apparatus is now allotted tor the sole use ot this particular line. ln like manner any desired number oil other lines similar to line A may be extended to the corresponding individualmechanisms at the observing operators position by means ot' other plug and jack connectors. F or example. a group of 'forty lines served by the line linderswit ches may be connected to the observing position at a time whereby the observing operator may take notations ol the service being rendered on these lines.

17Vhere subscribers lines. such as B shown inthe upper part of Fig. 1, are served by line switches, the extension ot the lines through the main and intermediate trames is substantially the same although the method ot connecting the. line to the observing position diil'ers somewhat. For example, the heat coils are not removed but the entire connection is made at the intermediate dis- Then it is incasso tributing frame by means of the cords'V which terminate in plugs 112, 113, 11d and 115.Y

rllhe first three cords are attached as illustrated to the proper connecting points on the intermediate distributing frame by shoes 116 and 117, while the cord terminating in plug 115 is attached "to the back contact of the line relay by a suitable attachment clip. rlhe same is true of lines which terminate in individual Switches, namely, that any desired number thereof may be connected to the observing position at a time.

The equipment at the operators desk includes a talking set comprising a receiver 200 (Fig. 2) and a transmitter 229 and a plug and jack switch 201 for rendering the equipment effective. By means of his talking set the operator may converse with a calling` subscriber whose line has been connected to his position. Furthermore, there are provided two cycle couirte-rs213 and 225. These devices may consist of any well known mechanism responding to an alternating current and which serves to drive a counting member through one step for each cycle through which the current passes. For operating` the cycle counters, there is provided a driving,` fork 215 which may be adjusted to operate at any desired frequency. rlhe frequency of the driving fort will determine by means of an induction coil 214:, the frequency set up in the secondaryA circuit, and consequently, the frequency of the current flowing` through the cycle counters. In an obvious manner the distance through which the movable element of the cycle counter moves in response to a current of known frequency, may indicate the enact amount of time elapsing from the instant the counter is started in operation until the operation ceases. rlhe principle of such devices is an old and well known one for obtaining an accurate measurement of time. The cycle counter per se is not concerned particularly with the present invention and, therefore, it is not considered. necessary to describe its operation and mechanism in detail. It is merely one device for obtaining an accurate measurement of the time required for certain operations in the system to take place. Any other time measuring device might be used equally as well provided it gave the required degree of accuracy. The cycle counter 213, as will be hereinafter described, is used for counting` the time ela-psing from the instant the subscriber initiates a call until a sender is at-- tached tohis line ready to receive impulses. The cycle counter 225 is used for countingl the time between the initiation of the call and the instant when the first impulse is sent from the substation.

ln addition, the operatcrs desk equipped with a pen register mechanism consisting of a magnet 208, the armature of which carries a pen arranged to engage a movin 0' tape to record the nature of the impulses sont out over the calling line.

Cert-ain other devices to be described here inafter are also located at the operators position for making observations of message registration and coin operations.

The system in general and the apparatus involved therein having been outlined above, a description will now be given of the detailed operation. To this end it is assumed at `liist that the observing operator Wishes to inspect the service being rendered on a certain zgroup of subscribers lines served by line finder switches. To do this, the operator removes the heat coils 126 of each line and connects such line, as'hereinbefore ein plained, to the connecting circuit leading to the observing desk by means of the plug` ended v'connecting cords. Since the identity of each of the several connecting circuits is known, the identity of the lines to which they are made individual, respectively, is also readily determined.

After having connected up a group of lines on which the service is t-obe inspected, the observing' operator renders his equipment effective for association with any line in the group that calls by completing the plug' and jack connection 201. The insertion of these plugs in the jacksextends the conductor 204: over the spring vcontacts 203 to conductor 231. rEhe conductor 231 leads through the upper contact of relay 232 tor ground through the left normal contact of release key 209. The conductor 204` extends over parallel paths to the inner armatures of each of the. several relays 300, only one of which is shown. There is a relay 300 iiidividual to each connecting circuit, and consequently, individual to the particular subscribers line associated with the operators position by means of such connecting Vcircuit. rlhe relay 300 corresponds to the line rela and enero'izes at the same instant the line relay is ope-rated. Whenever one of these relays operates, it connects they common conductor 2011 through its armature and contact to the winding of an individual relay suoli as relays 302 and 303 as will presently be described. W ith the apparatus thus in condition to ina-ke observations, it is now assumed that the subscriber of line A initiates a call.-

Upon removing his receiver from thel conductor 360, conductor 104, tip of jack 119,

tipof/plug 122, conductor 149, uppermost spring of plug 125, through the intermediate distributing frame, to ground at the right contact of relay 151. The line relay i152' becomes energized in this circuit and in the well known manner causes-theline finder 132 to start in operation, searching for theV subscribers line: The-line iinder 132ymayalso-be of the panel power drivenl type provided with a plurality of sets'of brushes-arranged to be tripped when operatedin the manner described in thev patent to J. L. MoQuarrie, No. 1,177,044, patented March 2S, 1916.

At the same-instant relay, 152- energizes, thefrelay; 300, also included-inseries therewith, attracts Yits i armatures; The; relay* 300 extends thecommonD conductor 204 through its inner armature and contact, inner backcontactgof relay 304, outer contact of relay 305, right-hand winding ofv relay 302, make-before-break Contact at the left-hand armature ofy relay 306, winding of relay 307, to battery. The individual3 relay 302 andthe common relay 307 become operated inithiszcircuit. lRelayv 302 closes a holding circuit for'l itself traceable from battery, through Vthel left-hand winding and inner left ,front contact of said relay, winding of :relay: 306, conductor 210, right contact of key 209,'to ground. Relay 306 energizes in series-with the locking circuit of relay 302 and opens the original energizing circuit of relay 302 which included the winding of relay 307. Relay 307, however, remains energized in a circuit from battery, through its winding, the make-before-break contact at the left armature of relay 306, thence. to ground over conductor 210; Relay 302 closes a circuit from battery, through the winding of'relay 305, inner left front contact: of relay 302, and thence to ground over theV conductor 210`as previously'trace'd. Relay 305 operatesV and creates a second break point in the" original energizing' circuit of' relay 302. In parallel to the relay 305, relay` 302 completes a circuit: forthelamp 301' which is individual to the connecting circuit, and consequently, individual to the calling line A. The lanip 301 illuminatesv and advisesthe operator that a call hasbeen initiated on this parti'cular line:

The relay 302, furthermore, extendsF the circuit` 308, 309 leadingvifroin` the? operator-"s talking set by way of* conductors 102 and' 103l thro-ugh to the subscribersfi line conductors145" and 146. In other words', the energization of relay 302 causes the extension' oi" the line A to' the observing operators telephoneequipment, whereby conversation may be held between the subscriber and the operator. Another result of the energization of relay 302 is the closure ot a circuit for relay 322. This circuit may be tracted from battery, through the windingsofrrelay 322, left Contact of relay conductor 309, inner right front contact of relay 302, conductor 103, sleeve of jack 120.

sleeve of plug 123.` conductor 148, next to the lower contact of plug` 125, conductor 146, thence over the line A. returning` by conductor 145, next to the upper spring of plug 125, conductor 147, tip of plug 1.23. jack-220, conductor 102, outer right con tact of relay 302, conductor 308, right contact of relay 323, to ground. Relay 322 operates and completes a circuit from baltery, through theleft-hand winding of relay 324, contact of relay 322. left and back contact of relay 314, conductor 210, to ground at key 209'. Relay 324 operates and closes a circuit from battery, through the winding of relay 325, inner left Contact of relay 324, left back contact of relay 314. to ground over conductor 210. Relay 325. upon energizing, closes a circuit frein battery, through its winding and right contact, winding of relay 314, conductor 210, to ground. Relay 314, however, cannot energize in this circuit since it is shunted out by the direct circuit to ground previously traced through the winding of relay 325 and inner left contact oi relay 324. Therefore, as long as relay 324 remains operated` the relay 314 isheld sliunted and cannotv become energized. Relay 325 also closes a circuit from battery, through the winding of relay 326, left contact of relay 325, to ground over conductor 210.

Vith relays 300 and 302 operated. a eircuit is closed from ground, over conductor 204, inner contact of relay 300, outer lett Contact of relay 302, conductors 311 and 327, leftfback contact of relay 323. winding` of relay 329, to battery. Relay 329 operates and completes a circuit troni battery.y through its winding and the windingot rclay 328 in series, right Contact of relay 329, to ground'by way of conductor 210. Relay 3,28, however, cannot energize since il is shunted outvby the direct circuit to ground traced through the contacts ot relays 300 and 302.

The observing equipment at the operators equipment is now connected to the subscribers line A, which connection has taken place'instantly in response to the initiation ofa call onA said line. Should another line in the-groupassociaited with the operator`s posit-ion by means of the plug and j ack connections originate a call at any time during the connectionv of the position with the line A, provision is made whereby said second linewill be ineffective to cause thetcontitl lill

nection of the operators position thereto. rllhis und is accouolislied by rendering all remainiinggl relays 303, etc., which are individual to the other lines in the group inoperative in r onse the energization ot" their correiriponding relays 300. From inspecton or the drawing, it will be seen that the enogizing circuitthrough the righthand Winding of relay 302 extends from battery, tl'irougli the Winding of relay 307 and over the malreebelorebreak Contact of relay The conductor 330 leading from the contact of relay 306 is multipled to the operating winding oi all relays 302. 303, etc. Since the relay 302 is energized and the connnon relay 306 is: also operated., the conductor 330 is opened at the make-beforebreak contact ot the said latter relay and, hence, no other relay 303, etc., can have its ope-rating circuit closed due to the initiation oft a call oic the line to which it is indivi dual.

at the instance the relay 307 attracts its arn'iatures, circuits are closed for supplying alternating current tv 'the cycle counters 213 and 223 in order that these devices may vWilence to count time from the initiation the call, The circuit for counter 2.13 may be traced from battery, through the tip oi jack 2li, tip of plug 212, thence through the counter l, sleeve of plug 212, sleeve of jack 211, `tl'irough the right-hand Winding of coil. 214., conductor 216, lowermost contact. oit relay 217, conductor 213, outer contact of relay 307, inner right contact of relay 312, conductor 313, sleeve ol'l jack 219, sleeve ot plug 220, through the counter 213, tip ol" plug 220, tip of jack 219, to ground. rlhe circuit. for applying current to the other counter 225 may be traced from battery through the tip oi jack 223, tip of plug 2215s, through the counter 225, sleeve of plug 22a', sleere ot lack 223, thence through the rightehand windings ot coil 214-, conductor 216., lowermost Contact oi relay 217, con-- ducto-r 213, outer contact of relay 307, right contact ci relay 514i, conductor 315, sleeve oit lr sleeve ot plug 226, through 'the counter tip of plug 226, tip of aclr 227, to ground.

#is soon as the line `finder switch 132 advances its lnfushes onto the terminals of the calling subscribei"s line a circuit is complel'edv in the usual well known manner for the ierglzation ol5 the cut-oilj relay 151. rlhis circuit leads trom source of battery current over the next to the lower' brush and contact of lnder l? through the Winding ot relay h vto grorud. i parallel circuit closed througn the intermediate distrib ting trame to conductor 156, tip of i, l c; 2l, tip ci" incl-z 121. conductor 106, the i" ral switch 321 in its position shown, co -icc 319. manual switch 31S, through the 3' relay 317 to ground.

`the observing equipment is en It may be noted at this point that when ,f fed for taking observations on lines which are served by line inder switches, the switch 321 is :in the position indicated the switch 331 is opened and the switch 332 is ch ed as indicated. These. switches are ordinary manual devices adjusted by the operator.

The cutoff relay 151 opens: the circuit of Athe line relay 152 and also the circuit ot re` lay 300. Relay 317, upon energiznfr closes a circuit for the slow relay 3011.

lli/'hen relay 300 4becomes deenergized. it opens the shunt around the Winding of relay 328 and this relay operates in series with relay 329. Relay 328 closes a circuit for the illumination of lamp 333, notifying` the observe;l that the subscribens line has been found.

l/Vhen the subscribers line is exteiided to an idle register sender 135, the sender selector having chosen an idle .sender in the manner set fort-h in the above-mentioned patent to F. A. Stearn and F. el'. Scudder, No. 1,395,977, issued November 1, 1921, the impulse relay of the selected sender is con nected in circuit With the subscribefs line including the individual relay 300 of the observing equipment. This circuit leads from battery through the Winding ot the impulse relay (not shown) in the register sender 135, left-hand contact of spring 160, next to the upper brush of' 'the line inder 132, through the intermediate distributingl 'frame` lowermost spring of plug 125, conductor 150, through the plug 122 and jack 119 to conductor 105, Winding of relay 300, conductor 103, through the jack 120 and plug` 123, conductor 14:8, next to the lower spring of plug 125, over the loop of the subscriber-s line, next to the upper spring` ot plug' 125, conductor 147, through the plug 123 and jack 120 to conductor 102, conductor 360, 'conductor 1011, through the jack 119 and plug 122 to conductor M9, thence through the intermediate distributing trame, through the uppermost brush ot the `finder 132, lower left Contact of spring 161 and thence to ground at the register sender 135. Relay 300 again operates in the circuit traced and completes a circuit from ground over conductor 204C, inner cci" t of relay 300, outer lett contact ot relay conductors 311 and 327, left front contact of relay 328, Contact of relay 362,-Windiiw of relay 312 t-o battery. Relay 312 opera and completes a circuit trom. battentv through its Winding and the Winding` ol relay 362 in series, left contact of relay 312, conductor 363, left normal contact of lrey 209, to ground. Relay 362, however, cannot oper-atein this circuit since it is shunted by the circuit closed through the contact oi relay 300. Relay 312 upon attracting its armatures opens the circuit previously traced over conductor 313 tor the flow of ci rrent through the cycle counter 213. The cycle counter 213 thereupon ceases its operation, having measured the time elapsing between the initiation of the call on the subscribers line, and the instant when an idle register sender 135 becomes attached to such line ready to receive impulses transmitted from the subscribers dial. The reading from this counter may be taken at any desired time by the observer. Relay 312 also closes a circuit from battery through the winding of relay 335, outer right contact of relay 312 to ground over conductor 210. Relay serves to prevent the closure of the circuit of relay 336 for a purpose. which will become obvious hereinafter.

v1t will be recalled that the relay 322 was connected in the subscribers line A at the time relay 302 became energized. YVhen, following the original energization of relay 322, the subscribers line is extended to the register `sender 135 and the impulse relay thereof is included in series with the calling line, the flow of current through the relay 322 becomes diminished sutliciently to permit the vrelease of said latter relay. Relay 322 opens the circuit of the left-hand winding of relay 324, but this relay remains locked in a circuit from battery through its .right-hand winding and right contact, conductor 364, right contact of relay 305, inner front contact of relay 304, inner contact of 'relay 300 to ground over conductor 204. Therefore, relay 324 is not permitted to deenergize and remove the shunt around the winding of relay 314 at the time relay 322 becomes deenergized. Immediately that the relay 312 operates, which occurs soon after the extension of the subscribers line to the register sender, a circuit is closed from battery through the right-hand Winding of relay 323, outer right contact of relay 312 to ground over conductor 210. yRelay 323 operates and disconnects the relay 322 from the conductors 303 and 309wto prevent the reenergization of said latter relay. Relay 312 also closes a circuit from battery through the lamp 334, outer v right contact of relay312 to the grounded vconductor 210. The lamp 334 advises the operator thatv an idle register sender has been seized.

It is assumed that the subscriber at substation A has allowed a suflicient time for the apparatus at the central otlice to associate asender with his line following the initiation of the call. He then manipulates his dial to transmitthe first series of impulses corresponding to the wanted designation. Upon the lirst opening of the line by the impulse sender, the relay 300 becomes deenergized and opens the shunt around the winding of relay 362 and also opens the holding circuit of relay 324. Relay 362 operates in series with relay 312 and locks to the grounded conductor 303 over the circuit previously traced. The relay 324 upon releasing its armatures opens the shunt hereinbefore described around the winding of relay 314. Hela y 314 thereupon operates in series with relay 325 and locks to ground over the conductor 210. The relay 314 at its right-hand armature opens the circuit over conductor 315 l'or supplying current to the second cycle counter 225. This counter thereupon ceases to operate. having accurately measured the time elapsing between the initiation of the call and the instant when the lirst impulse was transmitted by the subscriber.

lf the observer wishes to take a record of the impulses transmitted by the calling subscriber, he may do so by inserting the plug 207 in the jack 206. At the time relay 302 first became operated, a circuit was closed for relay 233 traceable from battery through the winding of this relay, conductor 311, outer left contact of relay 302, cond ctor 310, inner contact of relay 300 to ground over conductor 204. Relay 233 operates and closes a circuit from battery through the winding of relay 205, 't'ront contact of relay 233 to ground through the lelt normal contact of ley 209. Relay 205 operates and locks in a circuit from batter through its winding and left contact and contacts of key 234 to ground at key 200. When impulses are transmitted by the subscriber, the relay 300 operates in response thereto and in so doing causes the corre pending operation of relay 233. For each deenergization of the relay 233, :a circuit is closed from battery through the sleerc of jack 206, sleeve of plug 207` winding of the pen register magnet 20S, tip of plug 207, tip of jack 20G, right contact el relay 205, back contact of relay 233 to ground at the release key 209. The magnet 203 attracts its armature and presses the pen against the moving paper 230 thereby pro ducing a graph of the impulse series.

Assume thatthe calling line is one on which a coin box is located. ln this ease coin collect or refund current will be applied to the line at some time during the release of the connection in the usual manner. 1t is desirable that the observing operator be notilied with respect to the operation ol the coin boX both as regards the character of the current applied and also the time and duration thereof. For this purpose. the lamps and 236 are provided, one of which signifies that coin collect current is being applied to the line. while the other signifies that refund current is being sont over the line. lf the call succeeds, a source of collecting current is applied and in addition to flowing over the subscribers line it also liows over the tip conductor through the intermediate distributing frame, thence in order that the observers attention may be attracted at this time, the relay 239, on energizing, completes a circuit for the buzzer 240. 1f, on the other hand, refund current is applied, its polarity being of an opposite character, both relays 237 and 238 are operated. In this event, a circuit is closed from battery through the winding of relay 233, lamp 235, front contacts of relays 238 and 23? to ground, causing the illumination of the lamp 235.

Should the calling subscribers line A be one which is equipped with a message register, it is also desirable that the observer be aware of the fact that the register is operated properly. At the time of disconnection, if the call proved to be successful, a message register source of current is applied in the usual manner over the lowermost brush of the finder switch 132, contact of the line relay 152, through the intermediate distributing frame, winding of the message register 158, thence over two parallel branches, one of which leads back through the distributing frame through the left front contact of the cut-off -relay 151 and to ground, and the other of which eX- tends over conductor 157, sleeve of plug 124, sleeve of j ack 121, conductor 107, inner left contact of relay 305, conductor 316, through the winding of relay 228 to ground. Relay 228 operates and closes a circuit from battery through the winding of relay 239, lamp 241, to ground at the contact of relay 228. rlhe lamp 241 and the buzzer 240 Vadvise the observer that t-he message register of the calling line has been properly operated.

After having completed his observations on the subscribers line A, the operator may lsconnect the equipment at his desk from said line, in order to render it connectible to seine other line in the group by manipulating the release key 209. Upon operating the ley 209, ground is removed from the conductors 210 and 363 thereby permitting relays ses, 30e, so?, Y305, ses, ses, ses, sie, 314, and 323 to become deenergized. The release of these relays also causes the nguishment of the lamps 301, 333 and The operation of key 209 also opens the holdingl circuit of relay 205.

lt will next be considered that the subscriber commences to manipulate his impulse transmitter too soon, that is, prior to the time that a register sender 135 has been seized and placed in condition to receive impulses. It will be recalled that the relay 300 is deenergized during the interval between the instant that the subscribers line hasbeen found by the line linder switch 132 and the instant that an idle register sender is attached with the mechanism. 1n this condition, the relays 322, 324, 325, 329 and 328 are operated, but relays 312, 362, 314 and 335 are still deenergized. When, therefore, the first impulse is transmitted the opening of the calling line also severs the circuit of relay 322 and this relay becomes deenergized. Relay 322 opens the circuit for the left-hand winding of relay' 324, and this latter relay becomes deenergized since the previously traced holding circuit through its right-hand winding is now opened due to the fact that the relay 300 is deenergized. Consequently, relay 324 retracts its armatures and opens the shunt circuit around the winding of relay 314. Relay 314 thereupon energizes in series with relay 325 and in so doing opens the circuit of the second cycle counter 225 to give a measurement of the time elapsing between the initiation of the call and the instant the subscriber commences to dial. Since the relay 312 has not operated due to the fact that a sender was not yet attached, the relay 335 is still inert and hence the release of relay 324 causes the closure of a circuit from battery through the winding of relay 336, contact of relay 335, outer left contact of relay 324, left contact of relay 325 to ground over conductor 210. Relay 336 operates and locks through its winding and contact to the grounded conductor 303. Relay 336 closes a circuit from battery through the lamp 337, contact or relay 33 conductor 363 to ground. The illumination of lamp 337 notiiies'the observer that the calling subscriber has commenced to inanipulate his dial prematurely-` He may communicate, if desirable, with the subscriber and explain to him that more time should be allowed following the removal of the receiver before the dial is operated. Disconnection of the observing equipment from the subscribers line takes place in the same manner as above explained by the depression of the release key 209.

A description will now be given of the arrangement provided for making it impossible for the observing operators equipment to become connected to a second subscribers line when said equipment is released froin a first subseribers line at any time subsequent to the initiation of a call on said second line. lt is obvious that the operators equipment should be associated with the line as soon as the call is initiated,

since it is necessary to measure the time elapsingfrom ,the inst-ant ofy initiation until the line has beenfound in the one case and until a sender has been attached in the other. Should the equipment be connected to a line after a call had partly progressed, the readings taken by the counters would not give the exact information required. Therefore, the circuits are so arranged that when the operator depresses the release key and releases the equipment from one subscribers line at a time a call. has partly progressed on some other line, the equipment cannot be associated with said second line and neither can it be associated with any line until the time arrives when there is no call existing on any line. This precaution insures that the equipment when once attached to` a line will' be in condition to enable the proper observations of the service thereon. 'Assume, now, that the. observing v equipment has been attached to the line A in the manner already explained and the operator desires to disconnect the same therefrom and depresses the key 209 at a time when a call has partly progressed on some other line with which the observing equipment is temporarilyv associated.

It Awill be noted that the conductor 204 is connected .through the contacts 203 of the jacks 201 to conductor 231 whence it extends over two parallel branches, one. of which may be traced as hereinbefore explained through the contacts of key 209 and the other branch through the winding of the relay 202. The relay 202 is shunted out so long as the key 209 remains in its normal condition. Therefore, the operation of the relay 300 at the time a callis initiated completes the conductor 204 through the winding of relay 202 as traced to battery, but relay .202 being shunted by the release key does not operate in series with the relay 302. When, however, the operator depresses the key 209 to release the equipment, a circuit is closed from battery through the winding of relay-232, left alternate contact of key 209 to ground. Relay 232 operates and at its upper armature opens the shuntcircuit around the winding of; relay 202; At this particular instant, since a second line is calling, the relay 300-individual to said line is energized and is extending a second branch of the common conductor 204 through to the right-hand winding of relay 303, which it may be assumed, is the relay individual tothe said'seoond line. This circuit after passing through the right-hand winding of relay 303 is then traceable through the make-beforebreak contact of relay 306 and the winding of relay 307 to battery, the relay 306 becoming deenergized immediately upon the operation of the key 209. This modified circuit through the operating winding of relay 303 yand the-winding of relay 307,'how- 'after the key 209 is release-d.

ever, includes the resistance of relay 202 which is comparatively high. Relay 202 operates, but its resistance being of such a high value prevents the operation of relays 303 and 307. cannot be operated, the operators equipment cannot be connected to the subscribei"s line to which said relay is individual, notwithstanding the fact that a call has been initiated thereon. The relay 202, in operating, closes a locking circuit. for relay 232 in order to maintain this latter relay energized This condition prevails until the relay 300 of the second calling line becomes deenergized, say, at the time the line linder finds the line. iVhen the corresponding relay 300 releases it opens the circuit through the winding of relay 202 and this relay becomes deenergized to open the circuit of relay 232. Relay 232, on deenergizing, recompletes the low resistance shunt around the winding of relay 202. Then now the line relay corresponding to relay 300 individual to the second calling line again operates at the time a register sender is attached, the conductor 204 is extended through the inner contact thereof, but still the circuit for the right-hand winding of relay 303 cannot be completed due to the fact that the relay corresponding to relay 304 individual to the line has been energized. Relay 304 is energized following the energization of relay 317 which occurs as heretofore explained at the time the line is found.

Should it so happen that a third subscribers line has a call in progress thereon at the time the line iinder vfinds the second calling line, the circuit arrangement is so taken that the operators position cannot be associated with this third line. Vhen the finder finds the second line, as explained, the individual relay 300 releases and opens the circuit including the winding of relay 202 and the right-hand winding of the connecting relay 303. Relay 202, however, cannot become deenergized since its circuit is closed over another parallel branch which leads in a similar manner through the contact of the relay 300 belonging to the third calling line, the right-hand winding of the relay 303 individual to such line, and thence through the winding of relay 307. The same condition is true with regard to as many lines as have calls co-existing thereon following the time that the operators equipment is' released from one subscribers line at the instant a call exists on another line. In other words, the equipment cannot be connected except at an instant when there is no call already existing on any line.

When it is desired to associate the equipment with subscribers lines served by line switches, the connections are made, as illustrated, in the upper part of Fig. l. In ad- Hence, since the relay 303 dition to connecting the different terminals on the intermediate distributing frame with the connecting circuit to the operators position, it is necessary in this case to disconnect the tip and ring straps 165 and 166. rlhis may be accomplished by unsoldering these straps on one side of the frame.

vWhen the subscriber ot line B initiates a call a circuit is closed in the usual manner for the line relay 118 and may be traced from ground through the left-hand winding of said relay, left contact of cut-off relay 142, conductor 140, tip of plug 112 and jack 108, conductor 104, conductor 360, conductor 102, tip of jack 109 and plug 113, thence over the line conductor 136, returning by way of conductor 1377 conductor 144, sleeve ot plug 113 and jack 109, conductor 103, winding of relay 300, conductor 105, sleeve ot jack 108 and plug 112, conductor 141, inner right contact ot relay 142, right winding of relay 118 to battery. The line relay` 118 operates and initiates the movement of the line switch 128 in the usual manner.

ln response to the energization o1' relay 300, the same series of operations occur at the operators equipment as describedv in connection with the line A. Relay 302 is operated, and in turn starts the energization of relays 306, 329, 305, 322, 324, 325 and 326. As soon as individual line switch 128 takes its lirst step, the off-normal contact 167 is closed, completing a` circuit from ground through said contact, conductor 153, tip of plug 115 and jack 111, conductor 106, thence through the manual switch 321, (which is now thrown to its alternate position) winding of relay 304, to battery. One point of ditference over the preceding operation to be noted in the present instance is that the relay 304 is operated immediately that the line switch commences its operation, whereas in the case of a subscribers line served by a line finder switch, this relay does not operate until the line has been found.

Then the line switch 128 finds an idle trunk leading to a district selector switch 130, the cut-ott relay 142 is operated, thereby disconnecting the line relay 118 and also opening the circuit of relay 300.- In response to the deenergization of relay 300, the same operations occur at the observers desk as previously explained. Relay 328 is operated and lamp 333 illuminated, notifying the operator that a district switch has been selected. When, subsequently, an idle register sender 131 is attached, the relay 300 becomes energized as hereinbefore described, causing` the actuation of relay 312 and the stopping of the cycle counter 213. In response to the first impulse sent out by the calling subscribers dial, relay 314 becomes operated and the second cycle counter 225 is arrested.

If the subscribers line B is one provided with a message register, metering current is applied at a suitable time over a circuit leading through the lowermost brush ot the line switch 128, thence through the intermediate distributing frame, winding of the message register magnet 154, through the outer right contact and right-hand winding of relay 142 to ground. ln parallel with this circuit a branch leads from the terminal of the intermediate distributing trame, thence over conductor 155, sleeve of plug 114 and jack 110, conductor 107, inner lett contact of relay 305, conductor 316, winding of relay 228, to ground. Relay 228 causes the illumination of lamp 241 to notify the operator that the message register is being operated.

All other operations are substantially the same as hereinbeiore described in detail in connection with the observation made on the subscribers line A.

lVhen the observing equipment is used to make observations on subscribers lines in a step-by-step switching system, the connection of the equipment may be made in substantially the same manner as shown in the lower part ot Fig. 1 by use of cord circuits which lead from the main distributing trame to the j aclrs provided Jfor this purpose. The heat coils at the anain distributing frame are removed as in thel case previously explained. The circuits and apparatus shown in Fig. 3 respond to the operation of the line switches during the extension of the subscriberas line in the step-by-step system, during the initiation of a call for controlling the observing devices at the position shown in Fig. 2 in substantially the same manner as already described in detail.

In case of observations made on subscribers lines in a step-by-step system, the cycle counter 213 would serve to measure the time from the initiation of the call to the instant when the subscribers line had been extended to a iirst selector switch ready to receive impulses. The cycle counter 225 would be employed for taking a measurement of the time elapsing between the initiation of the call and the instant when the subscriber operates his dial. 1t will be obvious how the pen register mechanism, the message register signals and the other elements associated with the observers desk are operated to give the same records and indications for a subscribers line in a stepby-step system as for the lines A or B terminating in an oiiice where power driven switches are involved.

What is claimed is:

1. In a telephone system, a plurality of lines, an operators position, means for connecting the operators position to one of said lines, means for connecting the operators position to a second line, and means for rendering said last connecting means ineiiiective when tlie operators position is disconnected from the first line subsequent to the iiiitiatioli of tlie call on said secolid lilie.

2. Ili a telepliolie systelii, a plurality of lilies, an Operators position, iliealis for connecting tlie operators position to one or said lines, niealis :tor disconnecting tlie positioli from said lilie, liieans for coiinectilig tlie operators position to a secolid lilie, alid niealis for rendering said last connecting iiiealis ineiiective Wlieli tlie operators position is disconnected from tlie lirst lilie subsequent to tlie-iiiitiatioli of tlie call on said second line. y

3. In a telepliolie systelii, a plurality of lilies, an operators position colnnioll to'said lilies, liieans respolisive to tlie initiation of a call on one of said lilies for coliiiectilig tlie operators position to sucli lilie, lnealis for disconliectilig tlie position from saidline, means responsive to tlie initiation of a call on a second lille for coliliectilig tlie operators position to said second lille, alid liiealis for rendering said last connecting liiealis ineliective Wlien tlie operators position is disconnected from tlie first lilie at a time subsequent to tlie initiation of tlie call on said second line.

4.In a telepliolie system, a plurality oi' lines, an operators position commoli to said lines, means for connecting tlie operators position to one of said lilies, means for rendering said position `non-connectible to liiore tliali one line at a time, means for disconnecting tlie position from -said line, means responsive tothe initiation of a call on a second lille for` connecting tlie operators position to said second line, alid means for rendering said last connecting means ineffective Wlien said position is disconnected Jfrolntlie lfirst lilie subsequent to tlie initiation of tlie call on said second lilie.

5. In a teleplione systelii, a plurality of lilies, an operators position, means ilidividualto one of said lines for connecting tlie operators position to said lilie, means iiidividualto a second. lilie for connecting tlie operators position to said second line, andmeans for renderilig said last connectilig means ineffective Wlieii tlie operators position is disconnected from tlie lirst liiie subsequent to tlie initiation of tlie call oli said second line.

6. In a teleplione system, a plurality of lilies, an operators position, a connecting relay individual to one 'of said lilies for connecting tlie operators position to sucli lilie, means for disconnecting tlie position from said line, a connecting relay individual to a secondline aiid responsive to tlle initiation of a call tliereon for connecting the operators position toy said second lille, alid means for rendering said last coiiiiectilig` relay ineiective Wlien tlie operators position is disconnected from tlie rst line subsequent to tlie initiation of tlie call oli said second lille.

vi'. In a telephone system, a plurality ol lines, an operators position, means illdividual to olie ot said lilies 'for connecting tlle operators position thereto, means comllnoli to all of said lilies tor rendering tlle operators position noli-connectible to more tliali one lille at a time, means iordiscoliliectilig tlie operators position lroln said line, means individual to a second lilie and responsive to tlle initiation of a call tliel'eon for connecting tlie operators position to sucll second line, alid means for rendering said last connecting means ineffective ivlleli the operators position is disconnected tl-oni tlie lirst lilie subsequent to tlie initiation oit tlie call oli said second line.

8. In a telepliolie system, a plurality or lilies, ali operators position, means controlled by tlie operator for rendering said position coliliectible to any ot said lilies, means for connecting tlie operators position to one of said lilies, means controlled by tlle operator for disconnecting tlie position from said liiie, liieaiis responsiveto tlle initiation of a call on a second lille for connecting tlle operators position to sucli second line, aiid means for reliderilig said last connecting liiealis ilieifective vvlieli tlie operators positioli is disconnected from tlie first lilie slibsequent to tlie initiation of tlie call on said second liiie.

9. In a telepliolie system, a plurality of lilies, ali operators position, means for associatilig said position Witli a group of said lilies, said group containing any desired number of lilies, means for connecting tlie operators positioli to one of said lines,

liieaiis for disconnecting tlie position from said line, liiealis responsive to tlie initiation of a call oli a second lilie for connecting tlie operators position to sucli second lilie, and means for relideriiig tlie last connecting liiealis inelective Wlieli tlie operators positioli is disconnected from tlie first lilie subsequent to tlie initiation of tlie call on said second line l0. In a teleplllone system, a plurality ol lilies, all opera-tofs position, an observing liieclialiisln at said position tor observing the service on said lilies, means toi' conl nectilig said mechanism to one ot said lines, liiealis for disconnecting said lneclianisni from said liiie, means responsive. to tlie initiation of a call oii a. secolid liiie for colinectillg tlie observing liieclialiislil to said secolid line, and means 'lor renderingsaid last coliiiectiiig mea-lis ineffective when tlie said meeliaiiislii is discoliliected from tlie first line subsequent to tlie initiation ot tlie call on said second liiie.

ll. In a telepliolie system, a. plurality oi lilies, an operators posit-ion, means 'for alltoniatically extending one of said lines, means lll) 1,504,230 Y il for connecting the operators position to such line, means :tor disconnecting the position from said line, means responsive to the initiation ot a call on a second line for automatically extending sucli line7 means responsive to the initiation of the call on said second line for connecting the operators. position thereto, and means for rendering said last connecting means ineffective when the operators position is disconnected from the iirst line subsequent to the initiation of the call on said second line.

12. In a telephone system, a plurality of lines, an operators position, automatic switches responsive to the initiation of a call on one of said lines for extending such line, means responsive to the initiation ot' said call for connecting the operators position to said line, means tor disconnecting the position from said line, said automatic switches being responsive to the initiation of a call on a second line for extending suoli line, means responsive to the initiation oi the call on said second line for connect-ing,l the operators position thereto, and means tor rendering said last connecting means ineii'ective when the operators position is disconnected from the iirst line subsequent to the initiation of the call on said second line.

i3. in a telephone system, a plurality oi lines, an operators position, a plurality of automatic switches, means responsive to the initiation ot a call on one ot said lines for operating said switches to extend such line, means for connecting the operators position to said line, means for disconnecting the position from said line, means responsive to the initiation of the call on a second line for operating the automatic switches to extend such second line, means responsive to the initiation of the call on said second line for connecting the operators position thereto, and means ior rendering said last connecting means ineffective when the operator`s position is disconnected from the lirst line at a time when said second line has been partly extended,

11i. In a telephone system, a plurality of lines, an operators position, a plurality ot automatic switches, means responsive to the initiation oi: a call on one of said lines for operating said switches to extend such line, means responsive t-o the initiation oi said call for connecting the operators position to said line, means for disconnecting,` the operators position from said line, means responsive to the initiation oit' a call on a second line for operating the automatic switches to extend said second line, means responsive tothe initiation oit' the call on said second line for connecting,` the operators position thereto, and means for rendering said last connecting means ineffective when the operators position is disconnected 'from said ,(irst line at a time subsequent to the initiation of the call on said second line and before said second line has been completely extended.

l5. In a telephone system, a plurality of lines, an operators position, means responsive to the initiation of a call on one of said lines for automatically extending` s-uch line, means responsive to the initiation ot the call on said line for connecting the operators position thereto, means tor disconnecting the position from said line, means responsive to the initiation oi a call on a second line for automatically extending such second line, means responsive to the initiation of the call on said second line for connectine the operators position thereto, means at said position for measuring` the time required for the extension of said lines7 and means for rendering said last connecting means inetfective when the operators position is disconnected from the iii-st line subsequent to the initiation of the call on said second line and before suoli second line has been extended to a certain point.

16. In a telephone system, a plurality oi lines, an operators position, means for connecting` the operators position to one ot said lines, means for disconnecting` the position from said line, means responsive to the initiation oi a call on a second line for connecting,` the operators position thereto.` and means for delaying` the connection of the operators position to a second line until the time arrives following the disconnection of said position from the first line when no call exists on any line.

17. In a telephone'system, a plurality oit lines, an operators position, means for connecting the operators position to one ot said lines, means for disconnecting the position from said line, means responsive to the initiation of a call on a second line for connecting the operators position thereto, and means controlled by said disconnecting` means for delaying' the connection of the operators position to a second line until the time arrives following the disconnection of said position from the irst line when no call exists on any line.

18. In a telephone system, a line, an operators position, means for extending' said line, means for connectingv the operators position to such line, means for sending impulses over said line. means at the operators position 'lor measuring' the time between the initiation of a call on said line and the instant when the same is extended to a certain point, and means for signaling1 the operator it impulses are sent over the line before such line has been extended to said point.

19. In a telephone system, a line, an operators position, means responsive to the initiation of the call on said line tor extending lli) the same, means for connecting the operators position to such line, means for sending impulses over said line, means at the operators position for measuring` the time between the initiation of the Call and the instant when said line is extended to a eertain point, and a signal lamp at the operators position rendered ei'eotive if impulses are sent over the line before the-same has been extended to said point.

20. in a telephone system, a line, an operators positionl` means for extendingsaid line, means for Connecting,` the operators position to said line, means for sending impulses over said line, means at the operators position for measuring the interval between the initiation of the Call on said line and the instant When said impulses are transmitted, and means for signaling the operator if said impulses are transmitted over the line before such line has been extended to certain point.

9,1.. ln a telephone system,` a line, an operators position, means for extending said line, means for connecting the operators position to said line, means for sendingl impulses over said line, means for measuring` the interval between the initiation of a eall on said line and the time When said line is extended to a Certain point, means for measuring the interval between the initiation of said call and the instant when inlpulses are transmitted over said line, and means for signaling the operator it impulses are transmitted over the line before such line has been extended to said point.

22. In a telephone system, a line, an operators position, means for extending` said line, means for connecting the operatofs position to such line, means ior sending,T impulses over said line, means at the operator-s position for taking a record of the impulses transmitted, and means for signaling,- the operator if such impulses are sent over the line before said line has been extended to a certain point.

23. ln a telephone system, a line, an operators position, means tor extending said line, means for Connecting the operators position to said line, means for sending` impulses over said line, means at the operators position for making a graphie record oit the impulses transmitted`r and means for signaling` the operator i'fi impulses are sent over the line before said line has been extended to a certain point.

ln Witness whereof, l hereunto subscribe my name this 18th day of October, A. D.

JOHN W. GOODERHAM.

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