US1553327A - Telephone-exchange system - Google Patents

Description

Sept. l5, 1925. 1,553,327l

F. N. REEVES TELEPHONE EXCHANGE SYSTEM Filed Dec. 28, 1922 I5 Sheets-Sheet l .C @www WENN N. QN QQ /H Ven/0%.- fdH/f /l/. Ree ves by L Sept. 15, 1925. l 1,553,327l F. N. REEVES i TELEPHONE EXCHANGE SYSTEM Filed Deo. 28, 1922 I5 Sheets-Sheet 2 l/M vn fok.' Dank /V Ree ves ffy WMA-ffy.

Sept. l5, 1925;

' F. N. REEVES TELEPHONE EXCHANGE SYSTEM Filed Dec. 28. 1922 3 Sheets-Sheet 5 mm ,M

V on Patented Sept. 15, 1925.

UNITED STATEve-s FFICE.

FRANK N.Y Risavns,y -or NEWARK, JERSEY, ASSIGNOR 'ro WESTERN ELEc'rnrc COMPANY, INCORPORATED, 0F NEW YORK, N. Y., A CORPORATION oF NEW YORK.

iinLHoNnj-XCHANGE SYSTEM.

Appneation med necembei2s, 192'2. serial No. 609,377,

To all whom t may concern.' I

Be it known that I, FRANK a citizen of the United States of America,

residing atNewark, in the county of Essex:

in a telephone 'exchange .systeml during the period when the exchange is being changed from a manual to an z'm'tornaticv operating basis, there are certain oiii'cesY which are equipped kwith machine'jswitching apparatus and function for calls locl thereto on a full mechanicalbasis and other ofiices which are equipped with re'gtilar manual equipment. If the oiiices of the exchange area are widely separated, it is not feasible because of the expense involved, to extend direct trunks between each and every office in the area and, therefore; in order to enable a. subscriber in an ofce to obtain a connection with any other subscriber in the exchange area, tandem switchiing oiiices are provided at convenient points inthe exchange area from which trunks radiate to all ofiices adjacent thereto. Thus, foregiample, if a subscriber in one manual ofiice desire-s to obtain aV connection with a subscribers line terminating in" another manual oiiice remote therefrom, the A. operator of the cnice in which the calling line terminates will first obt-aina connec` tion withthe tandem switching oiiice, whereupon the B or cordless operator Vof such` tandem office will semi-automatically eX- tend the connection to the manual oiiic'ein'` which the desired line terminates, where thev terminating operator will complete the conI` nection.

Under this method of operation, the operator at the tandem office receives the designation of the desired line overa call circuit from the originating or A operator and writes up the designation upon her keyboard. The office sender associated with her position then proceeds to cause the operation of selector switches to select an idle trunk extending to the oiiice inl which the desired Vline terminates and to cause thev line designation to be dislayed upon a call indicator yassociated wit the terminating operators position in the selected oiiice.

Inorder that at all times the apparatus at .the B. or `cordless operators position of the tandem switching oliice shall be main'- tained at the highest possible degree ofx efficiency so thatthe line designations shall be accurately displayed at the terminating oliijce, it is desirable that means lbe provided for testing the accuracy with which the line designations which are' recorded upon the keyboard o f any cordlessoperators position are transferred over trunks. y

It is, therefore, the object of the present invention to provide a testing circuit which may be associated with the apparatus of an operators position for testing ythe accuracy with which such apparatus functions in transferring line designations.

A further object ofthe invention is to provide an indicator observable from any pointin operating room for displaying designations of lines.

p outgoing In a tandemswitching oiice of the character above described, desks are providedin theo-perating room upon which the B or cordless l:positions are located. In accordance with this invention one 'or more indicating devices are conveniently positioned in the operating'room, each comprising lamp boXes which may be observed from any operators position. The lamp boxes' are designed to display any line designation which the operator, at any position may record Aon the keyboard of her-position; c These indicating devices are accessible from any operators position through a testing trunk which terminates either in lthe district or office selector multiples. The district or office .selecto-'rs are -directed yto the terminals of this trunk through the depression of oiiice -coordinate keys of the operators keyboard, In addition, each operato-rs position is provided with a jackfor, enabling the operator to connect her headset with the test trunk if she desires to conduct a talking test. Thus,- if it is desired to test the apparatus of any oper'ators posit-ion, the proper coordinate keys of the operators lkeyboardare depressed for causing a district or cnice seleC,"

tor to select the test line terrninavtingr in they indicating devices, and numerical keys corico respondings to the number with which the position apparatus is to be tested are then depressed. lf the indicating device thereupon dispiays correctly the number recorded, it is then known that the operators sending apparatus has functioned accurately. In this manner, the position may be tested with a series of numbers which will fully demonstrate its ability to operate accurately.

It is thought that the features of the invention will be best understood from a consideration of the following description taken in connection with the accompanying drawings.

Fig. 1 shows diagrammatically a trunk incoming from a manual office terminating in a district selector at a cordless operators position of a tandem switching ofhce, a keyboard and sender at such operators position and the outgoing end of a test trunk accessible to all cordless district selectors of the office.

Fig. 2 shows controlling circuits of an indicating device in which the test trunk of Fig. 1 terminates.

Fig. 3 shows lamp boxes of the indicating device and register controlling relays therefor.

Fig. 4 shows in detail the arrangement of lamps in one of the lamp boxes of Fig. 3 and the circuits of the controlling sequence switch associated therewith.

Fig. 5 shows in a diagrammatic manner the apparatus and circuits involved in eX- tending a connection from a calling subscribers line in one manual office through the cordless position of a tandem office to a subscribers line terminating in a second manual office, or to the test indicator forming the subject matter of this invention.

Fig. l should be placed above Fig. 2, and Fig. 3 should be placed to the right of Fig. 2 with the lines extending to the adjoining margins of the figures in alignment for a consideration of the circuits as an entity. The apparatus of the cordless operators position, illustrated in Fig. 1, comprises a trunk circuit 104 terminating at its outgoing end in a jack at an A operators position in an originating office and terminating at the tandem switching office in the brushes of a panel-type district selector 150, a keyboard 100, a sender 101, a sender selector 103 and a trunk finder 102 for associating the keyboard 100 with an idle sender 101 and with the trunk circuit 104. This apparatus has not been fully disclosed herein since it enters only incidentally into the disclosure of this invention. For a full disclosure thereof, reference may be had to Patent No. 1,501,871, issued to F. A. Stearn, July 15, 1924.

Y The circuits and apparatus of Figs. 2 and 3 are of substantially the same type as disclosed in the Patent No. 1,464,084, issued to A-. E. Lundell and E. H. Clark, August 7, 1923, differing therefrom only in the employment of indicating lamps arranged in the manner shown in the patent to F. N. Reeves, 1,337,482, issued April 20, 1920. Four groups of lamp relays are shown in Fig. 3, each group controlling an indicator of the type disclosed in the aforesaid patent to F. N. Reeves and as disclosed in detail in Fig. 4. In order to simplify the disclosure the sequence switch and indicator associated with each group of register relays have not been disclosed in Fig. 3, these sequence switches being represented herein by the rectangles 300, 301, 302 and 303 and the indicators by the rectangles 304, 305, 306 and 307. In the consideration of the circuits of Fig. 3, the circuits of Fig. 4, are, therefore, to be substituted for the rectangles shown in Fig. 3.

Each of the indicators of Fig. 3 comprises a lamp box having transparent panels of the shape shown in dotted lines in Fig. 4 and seven groups of lamps, a group of lamps positioned behind each of said panels. These panels have been designated as 1 1, 2 2, 3-3, etc., in Fig. 4. Thus, to display the digits 0 to 9, inclusive, the lamps behind the seven panels are lighted through the setting of the associated sequence switch in the following combinations:

Sequence Digit. swi tch Lamps position.

0 2 1 2 3 a 6 7 1 3 3 6 2 4 1 3 4 5 7 3 5 1 3 4 6 7 4 6 2 3 4 6 5 7 l 2 4 6 7 6 8 y 1 2 4 5 6 7 7 9 1 3 G 8 10 1 2 3 4 5 6 7 9 11 1 2 3 4 I 6 7 In Fig. 3 the indicators have been shown as they would appear in displaying the designation 3578 although the controlling circuits are disclosed as in their normal position.

The sequence switches 110 and 410 may be of the same structure as disclosed in Patent 1,127,808, issued to J. N. Reynolds and C. F. Baldwin, February 9, 1915. Only a portion of the cams controlled by the switch 110 and a portion of the controlling circuits thereof have been disclosed in Fig. 1. For a full disclosure of the circuits thereof, reference may be had to the patent to F. A. Stearn hereinbefore referred to.

The apparatus employed and the manner in which it functions having now beenV briefiy described, it is thought that the invention will be better understood from a more detailed consideration of the manner in which the circuits are employed. T'wo types of tests may be conducted employing lli the apparatus employed herein. First a test of the B or cordless operators apparatus conducted entirely from such operators position and in connection with which no talking test is made and, a second test conducted in conjunction with an originating A operators position in connection with which test a talking connection is estab-lished between the A position and the B position under test. A test of the lirst character will lirst be considered, it being assumed that coordinate 'office keys of the keyboard 100 are depressed for routing the test call to the terminals of the test trunk 112 over the brushes of the district selector 150 and, that keys are depressed for displaying the designation of line upon the indicators of Fig. 3. 1t will be further assumed that for the purpose of making the test the trunk circuit 104 terminating in district selecto-r 150 is assigned for use by the B operator.

In the manner fully set forth in the afore said patent to F. A. Stearn upon the assignment of the trunk for use, the opera.- tors keyboard 100 is connected by the trunk huntingy switch 102 with the trunk 104 and an idle sender 101 is associated therewith by the sender selector 103. Thereupon, the

registers of the sender areset in accordance with the office and numerical designations recorded upon the keyboard 100 kand the sender proceeds vto function to set the brushes of the district selector 150 upon the terminals of the test trunk 112. As soon as the selector switch 150 has positioned its brushes upon the terminals of trunk 112, the sequence switch 110 associated with the dis-l trict selector advances to the selection-beyond position 11. The selected trunk 112 is now maintained busy to all other selector switches having access thereto by groimd po`- tential placed 1upon the multiples of the test terminal 107, over brush 111 and the right contacts of cam 113.

With sequence switch 1101 in position 11, a circuit is now established from battery, right winding of relay 114, right windingo coil 115, inner right armature and back contact of relay 116, upper armature and back contact of relay 117, terminal 105 and brush 108, contact of cam 118 (11), wiper 119 of the trunk finding switch 102, wiper 120 of the` sender selector switch 108, the controlling circuit of sender 101, wiper 121, wiper 122, lower contact of cam 123 (11), brush 109, 'terminal 106, lower armature and back contact of relay 117, inner leftarmature and back contact of relay 116, left winding of coil 115 to ground, through the left winding` of relay 114. vRelay 114 energizes in this circuit closing a circuit for relay 124 from ground at the armature and back contact of relay 200, conductor 201, armature and contact of relay 114, left winding of relay 124, outer armature and back contact of relay 125, conductor 126 to battery through the winding ot relay v202. Re lays 124 and 202 energize in this circuit, relay 124 closing a locking circuit for itsell" from battery through the winding oi'f relay 202, conductor 126, the outerl armature and back contact of relay 125, both windings of relay 124, right armature and contact thereof, outer left armature and back contact oit relay 116 to ground at the lower contact ot cam 113. Relay 124 also establishes a circuit 'for relay 117 which may be traced from battery through the winding or relay 117, left armature and Contact of relay 124, con-- ductor 127 to ground through the winding of relay 200. Vith relay 117 energized the circuit previously traced through the winding of relay 114 is opened at the armatures and back contacts of relay 117 and relay 114 thereupon retracts its armature opening the initial energizing circuit 4of relay 124.

Relay 202, upon energizing in series with relay124, closes an obvious circuit tor relay 203, which, at its armatures and back contacts removes ground from the conductors 204, 205, 206 and 207 leading through restoring contacts of cams on the sequence switches associated with the several Vindicators. Relay 202-at its inner right armature and contact closes an obvious circuit'tor relay 208, and, at its left arma-ture and contact connects ground to conductor 209 for furnishing locking ground for certain of the switching relays of Fig. 2. Relay`208, upon energizing, supplies a locking ground to the remaining switching relays of Fig. 2 and to the register relays of Fig. 3 and an operating ground to the armatures of control relays 210, 211 and 212, over conductor 216.

Vith relay 117 operated, a fundan'iental controlling circuit is established troni the sender 101 through the windings of' control relays 210, 211 and 212 which may be traced as previously described from the sender to the armatures of relay 117 and from thence as follows; upper armature and front contact of relay 117, conductor 128, inner right armature and back Contact ot switching relay 213, conductor 214, winding Gif-positively polarized relay 212, winding of negatively polarized relayA 211, winding of marginal relay 210, conductor 215, inner left armature and back contact of switching relay 213, conductor 129 to the lower armature and front contact of relay 117. The circuits are now in condition to receive the lirst set of code impulses corresponding to the stations designation of the number `recordedon the keyboard. Each set of code impulsesY in accordance with the well-known standard practice consists of; a maximum of 'four impulses.- The first and third impulses of each Vset are always either weak positive or are entirely omitted and the second and fourth her keyboard impulses are either weak or strong negative current.

1t has been assumed that the B operator has recorded the designation 3578-h/ upon rlherei'ore, the irst impulses new tran. Jd trom the sender 101 through the winding ot relays 210, 211 and 212 tor registering the stations designation lil confiprise a light negative impulse Jfollowed by a heavy negative impulse. ln response to the iirst light negative impulse the negatively polarized relay 211 energizes, closing a circuit from ground on conductor 216, through the armature and contact of relay 211, conductor 227, outer left armature and normal contact ot switching relay 213, conductor 228, left armature and back conoi'' relay 230, winding of relay 220 to battery through the lett winding of relay 230. Relay 220 energizes in this circuit, but relay -.30 does not receive sulicient currentto cause its energization. Relay 220, upon energizing, closes a circuit from battery through the lett winding of relay 230, the winding of relay 220, the right winding orq relay 230, the inner right armature and contact of relay 220 to ground on conductor 216. Relay 230, however, does not energize at this time since its right winding is shunted through the Contact of relay 211. Relay 220 at its outer right armature and front contact closes a circuit for the switching relay 218 which may be traced from battery through the winding of relay 218, the outer left armature and back contact of relay 217, the outer right armature and contact of relay 220 to ground on conductor 216. Relay 218, upon attracting its armatures, establishes a locking circuit tor itself from battery, through its winding, the winding of relay 217, the inner right armature and front contact of relay 218 to ground on conductor 216. Relay 217, however, does not energize at this time since its winding is shunted by a direct path to ground through the armature and contact of relay 220. As soon, however, as relay 211 deenergizes following the transmission of the first impulse of the stations code and removes the shunt from around the winding or' relay 230, relay 230 energizes in series with relay 220.

ln response to the second impulse of strong negative current, negatively polarized relay 211 again energizes and in addition marginal relay 210 also energizes. Relay 211 upon attracting' its armature, closes a circuit from battery, through the left winding of relay 230, left armature and front contact ot' this relay, conductor 228, outer lett armature and normal Contact of relay 213, conductor 227, armature and contactiof relay 211 to ground on conductor 216.

rThis direct circuit to ground shunts the winding or" relay 220 causing 1t to deener- 4tact to ground on conductor 216.

gize and release its armatures. Upon the release otl its outer right armature, the shunt around the winding of switching relay 217 is opened, but this relay is still maintained shunted over the inner right armature and contact of relay 230 to ground on conductor 216. Relay 210, upon energizing, closes a circuit from ground on conductor 216, over the armature and contact of relay 210, conductor 231, the outer right armature and front contact ol relay 230, the inner left armature and back contact of relay 217, conductor 292 to battery tirough the lett winding ot stations register relay 32-1. Relay 3211, upon energizing in this circuit, establishes a locking circuit tor itself 'from battery through both of its windings in series, its right armature and contact to ground on conductor 216. Upon the termination of the second, strong negative impulse ot the stations code, relays 210 and 211 deenergize, relay 211 opening the circuit through the left winding of relay 230. Relay 220 being at this time deeneroized, no other circuit exists for relay 230, and, consequently relay 230 becomes deenergized. TWhen relay 230 releases its armatures, the shunt around the winding of switching relay 217 is removed and this relay energzes in the locking circuit of relay 218. It will be noted that only one stations relay 324C has been operated. i

Since it has been assumed that the thousands digit of the line designation is 3, the thousands code will comprise a positive impulse followed by a weaknegative impulse and a strong negative impulse. ln response to the first positive impulse, the positively polarized relay 212 energizes, closing a circuit from ground on conductor 216, through the armature and contact of relay 212, conductor 253, the left armature land back contact oft relay 220, the left armature and front contact oia switching relay 218, the left armature and bac-ir contact ot switching relay 222, conductor 23-1 to battery through the left winding of thousands register yrelay 311. Relay 311, upon energizing, closes a` locking circuit for itself extending from battery, through both of its windings in series, its inner right armature and front con- Upon the termination of the first positive impulse, relay 212 deenergizes. 1n response -to the second impulse of weal negative current, the negatively polarized relay 211 energizes, closing the previously traced circuit through the winding of relay 220 and the left winding of relay 230; Relay 220 now energizes preparing an energizing circuit for relay 230 as previously described and establishing a circuit for the switching relay 222, from battery, through the winding of relay 222, the outer left armature and back contact of relay 221,y

the outer' left armature and front contactof CII lill) relay 217, outer right armature and contact of relay 220 to ground on conductor 216. Relay 222, upon energizing, closes a locking circuit for itself extending from battery through its winding, the winding of relay 221, the inner right armature and front contact of relay 222 to ground on conductor 216, but relay 221 being shuntedrat this time at the contact of relay 220 dees not energize in this locking circuit. Then the second negative impulse ceases, relay 211 deenergiz'es, opening the shunt around the right winding of relay 230, whereupon this relay energizes in series lwith relay 220.

ln response to the third impulse of strong nega-tive current, the negatively polarized relay 211 and marginal relay 210 both energize, relay 211 establishing the previously traced circuit from ground directly through the lef-t winding of relay 230 thereby shunting the winding of 'relay 220 and causing the deenergization thereof. Rel'ay 210, upon energizing, closes a circuit from ground on conductor 216, thro-ugh the armature and Contact of yrelay-210,l conductor 231, outer right armature and fro-nt contact of relay 230, .the inner left armature and front contact of relay 217, the inner left armature and back eontact of relay 221, conductor 235 to battery through the left winding of thousands registerv relay 308. Relay 308, upon energizing., 'closes a Vlocking circuit for itself extending from battery through both of its windings in series and the contact of its right armature to ground on conductor 216. `Upon the termination of the third impulse of the thousands code, relays 210 and 211 deenerg'iz'es, relay 211 opening the holding circuit of relay 230 permitting it to retract its armatures. Since at this time hoth relays 220 and 230 are deenergized, the shunt around the winding ofswitching relay y22 is' opened and relay 221 energizes in the holding circuit of relay ,222. The thousands register relays 308 Iand 311 have now been energized and locked. l

lt having been assumed that the hundreds digit of the line designation is 5, the hundreds `code of impulses will comprise a light negative impulse followed by a strong negative impulse. In response to the firstl impulse of ligh-t negative current, relay 211 energizes closing the previously traced circuit through the winding of relay7220 and the left winding of relay 230. Relay 220 energizes in this circuit, closing a holding circuit for itself through` both windings of relay 230, relay 230, however, remaining deenergiz'ed at this time. At its outer right arirrature and Contact, relay 220 establishes a circuit for switching relay 224 whichmay be traced from battery ythrough the winding of relay 224, the outer lef-t armature and back contact of relay 223, the outer lett armatures and vfront contacts 'of relays 221 and 217 the outer right armature and contact 'of relay 220 to ground on conductor 216. Relay 22,4, upon energizing, now establishes a holding circuit for itselfextending from battery through its winding, the winding of switching relay 223, the inner right armature and front Contact of relay 224- to ground on conductor 209. Upon the cessation of lthe first negative impulse of current, the shunt around the right wind- -ing of relay 230 is removed at the armature contact of relay 210, conductor 231, the, y

outer right armature and front contact of relay 230, the inner left armatures 'and front contacts of switching relays 217 yand 221, the inner left armature and back contact of switching relay 223, conductor 236 to battery through the left winding of hundreds register relay 312. Relay'312, upon energizing in this circuit, closes a locking circuit for itself extending from battery through both of its windings in series, its

right armature and contact to lground on conductor 216. UponV the cessation of the second and last of the. hundreds code of impulses, relays 210 and 211 become deenergized, relay 211 opening the circuit of relay 230 causing the latter relay to release its armatures Since at this time both relays 220 and 230 are deenergi'ze'd, the shunt around the winding of switching relay 223 is removed and this relay energizes in the holding circuit of relay 224. Only onel hundreds register relay 312, has been operated in response tothe hundreds code of impulses.

For registering the tens digit 7, the sender 101 transmits a code of impulses comprising two strong negative impulses. response to the first strong negative impulse the negatively polarized relay 211 and marginal relay 210 energize. Relay 211, -upon energizing, closes the previously traced circuit through the winding .of relay 220 and the left winding of relay 230, relay 220 closing a holding circuit for itself through both windings of relay 230. Relay 230, however, being shunted at this time atythe contact of relay 211 does notenergize. Relay 220 also closes a circuit for the switchn'grelay 226 which may be traced from battery through the windln" of relay 226, the outer left armature and ack contact of relay 225, the outer left armatures and front Inl contacts of relays 223, 221 and 217, the outer right armature of relay 220 to ground on conductor 216. Relay 226, upon energizing, closes a locking circuit for itself extending from battery, through its Winding, the Winding of relay 225, the inner right armature and Contact of relay 226 to ground on conductor 209. Relay 210, upon energizing, closes a circuit Which may be traced from ground on conductor 216, the armature and contact of relay 210, conductor 231, the outer right armature and back Contact of relay 230, the right armatures and front contacts of relays 21'?, 221 and 223, the inner right armature. and back contact of relay 225, conductor 237(w to battery through the left Winding of tens register relay 318. Relay 313, upon energizing in this circuit, closes a locking circuit for itself from battery, through both of its Windings in series, its inner right armature and front conta-etto ground on conductor 216. Upon the cessation of the first impulse of the tens code, relays 210 and 211 deenergize, relay 211 removing the shunt from around the right Winding of relay 230 permitting this relay to energize in series with relay 220;

In response to the second strong negative impulse of the tens code, relays 210 and 211 again energize, relay 211 closing a circuit from ground directly through the left Winding of relay 230 in snunt of the Winding of relay 220, causing the deenergization of this latter' relay. `Relay 210, upon energizing, establishes a circuit from ground on conductor 216, through the armature and contact of relay 210, conductor 231, the outer right armature and front contact of relay 230, the inner left armatures and front contacts of switching relays 217, 221 and 223, the outer right armature and back contact of relay 225, conductor 238 to battery, through the left Winding of tens register relay 316. Ftelay 316, upon energizing', closes a locking circuit for itself from battery through both of its windings in series, its right armature and Contact to ground on conductor 216. Upon the cessation of the secc-nd negative impulse, relays 210 and 211 deenergize, relay 211 opening the holding circuit of relay 230 whereupon relay 239 releases its armatures. Since at this time both relays 220 and 230 are deenergized, the shunt about the Winding of relay 225 is opened and this relay energizes in the holding circuit of relay 226. rlens register relays 316 and 318 have now been operated in response to the tens cede of impulses.

Since it has been assumed that the units Y digit of the line designation is 8, the sender 101 transmits a code of impulses comprising a positive impulse followed by two si'rong negative impulses. In response to the first positive impulse, the positively polarized relay 212 energizes, closing a circuit from ground on conductor 216, the armature and contact of relay 212, conductor 233, the left armature and back contact of relay 229, the left armatures and front contacts of relays 218 and 222, the outer left armatures and front contacts of relays 224 and 226, conductor 239 to battery through the left Winding of units register relay 323. Relay 323, upon energizing, locks from battery through both of its windings in series, its inner right armature and contact to ground on conductor 216. Upon the cessation of the first positive inipulse, relay 212 deenergizes.

In response to the second impulse of strong negative current, relays 210 and 211 energize, relay 211 closing the previously traced circuit through the Winding of relay 22() and the left Winding of relay 239. Relay 220, upon energizing, closes a holding circuit for itself through both of the Windings of relay 230, and a circuit for the switching relay 219, which latter circuit may be traced from battery, through the Winding of relay 219, the outer left armatures and front contacts of switching relays 225, 223, 221 and 217, the o-uter right armature and contact of relay 220 to ground on conductor 216. Relay 219 now closes a holding circuit for itself extending from battery through its Winding, the Winding of relay 213, the inner right armature and Contact of relay 219 to ground on conductor 209. Relay 210, upon energizing,rcloses a circuit from ground on conductor 216, the armature and contact of relay 210, conductor 231, the cuter right armature and back contact of relay 230, the right armatures and front contacts of relays 217, 221 and 223, the inner right armature and front contact of relay 225, conductor 240, to bat-- tery through the left Winding of units regis-1 ter relay 322. Relay 322, upon energizing in this circuit locks from battery through both its windings and the front contact et its inner right armature to ground on conductor 216. Upon the termination of this impulse, relays 210 and 211 deenergize, re` lay 211 removing the shunt from the right Winding of relay 230 whereupon relay 239 energizes in series With relay 220. Y

In response to the third impulse of strong negative current, relays 210 and 211 again energize, relay 211 closing a circuit from ground directly through the left Winding of relay 230 shunting down relay 220 which thereupon deenergizes. Relay 210, upon energizing, closes a circuit from ground on conductor 216 through the armature and contact of relay 210, conductor 231, the outer right armature and front contact of relay 230, the inner left armatures and front contacts of relays 217, 221, 223 and 225 conductor 241 to battery through the lll) left winding of units register relay 320. Relay 320 now locks from battery through both of its windings in series and the contact of its right armature to ground on conductor 216. Upon the termination of this impulse, relays 210 and 211 deenergize, relay 211 opening the circuit of relay 230 causing it to release its armatures. Since at this time the shunt about the winding of switching relay 213 is opened at contacts of both relays 220 and 230, relay 213 energizes in the locking circuit of relay 219. The impulses of the units code have now been transmitted and units register relays 320, 322 and 323 are locked energized. The entire designation of the number recorded upon the keyboard 100 at the B operators position has now been transferred t'o the register relays of the test indicator.

Atl the 'time a circuit was closed for the switching relay 219 during the transmission of the last orunits series of code impulses, a circuit was alsoclosed in parallel therewith through the winding of relay 242 to batterya Relay 242, upon energizing, closes a` holding circuit for itself extending from battery through its own winding, winding of relay 243, the inner armature and contact of `relay 242, conductor244, the outer right 'armature and contact of relay 219 to ground at the.v inner left armature and contact of relay 226-. Relay 243, however, does not energize in this holding circuit since its winding is shunted by direct ground through the armatures and contacts of relays 220 and 230 as long as either of the latter relays are energized. Relays 242 at its outer left armature -and contact establishes a circuit for relay 328 preparatory to lighting the selected stations lamp.- When the lastV code impulse of the units series has terminated, relays 220 and 230 bot-h become deenergized and relay 243 thereupon energizes in the holding circuit of relay 242. As soon as relay 243 operates, a circuit is closed for relay 246 which may be traced from battery throughthe winding of relay 246, conductor 245, to ground at the armature and contact 'of relay 243. Wit- h relays 242 and 246 energized circuits are now effective for causing the display of the entire line designation. Y Y

It will be recalled that in response to the thousands series of code impulses, register relays 308 and -311 were operated, relays 309 and 31.0 remaining in their unoperated positions. A circuit is now closed fromv ground throughV the uppermost armature land contactof relay 246, conductor 247 the left ari mature and front contact of relay 308, the alternate contacts associated with the outer left armature `of relay 311, the inner left armature and baclrcontact "of relay`310, conlductor 330, thence referring to Fig.f4

through the lower right contact of avcam corresponding to cam 412 (1 to 4) to battery-throughthe n'iagnet winding of sequence switch 3 00. The sequence switch is now advanced into position 5 where it is arrested since its driving circuit is opened at the lower right contact of the cam corresponding to cam 412 and no other driving circuit exists therefor.

lilith sequence switch 300 in position 5, the following lamp circuits are closed: ground, lower contact of the cam corresponding to cam 415 (4 to5), lamps 1 1 to battery; ground, upper right contact of said cam (2 to 6), lamps 3 3 to battery; ground lower right contact of the cam corresponding to cam 416 (4 to 8), lamps 4 4 to battery; ground, upper right contact of the cam corresponding to cam 416 (5 to 11), lamps 6 6 to battery; ground, upper left contact of the cam corresponding to cam 416 (4 to 5), lamps 7 7 to battery. Lamps 1 1, 3 3, 4 4, 6 6 and 7 7 are now lighted over the above traced circuits and in combination display thedigit 3 on the thousands indicator 304. Y

As 'a result yof the transmission of thehundreds code of impulses register relay 312 was operated, relays 313, 314 and 315 being unoperated. A circuit is now effective for advancing the sequence switch of the hundreds indicatorl 305, which may be traced from ground through the armature contact 248 of relay 246, vconductor 250, the left armature and front contact of relay 312, the outer left 'armature and back contact of relay 315, the outer rightarmatures and back contacts of relays 314 and 313, conduct-or 331, thence.

referring to Fig. 4, through the lower right contact of a cam corresponding to cam 413 (1 to 6), to battery, through the magnet winding of sequence switch 301. The sequence switch. designated by the rectangle 301 associated with the hundreds indicator 305 thereupon advances into position 7. Writh this sequence switch in position 7, circuits are established for the lamps ofthe hundreds indicator-as follows, reference be.- in'g had to Fig. 4: ground, lower contact of the cam corresponding to cam 415 (7 to 11) lamps 1 1, to battery; ground, upper left contact of the cam corresponding to cam 415 (6 to 8), lamps 2 2 to battery; ground, lower right contact of the cam corresponding to cam 416 (4 to 8), lamps 4 4 to battery; ground, upper rightr contact of the camV corresponding to cam 416 (5 to 11), lamps 6 6 tiobattery; ground, upper left contact of the cam corresponding to cam 416 (7 `to 8), lamps 7 7 to battery. Lamps 1 1, 2-2, 4 4, 6 6 and 7 7 are thus lighted for displaying the'digit 5 on the lhundreds indicator 305. a

y In response to the tens code of impulses', the tens register relays 316 and 318 were operated, relays 317 and 319 remaining unoperated. A circuit is, therefore, effective which may be traced from ground through the armature contact 249 of relay 246, conductor 251, the left armature and front con tact of relay 316, the outer left armature and back contact of relay 319, the outer right armature and front contact of relay 318, conductor 332, thence, referring to Fig. 4, through the upper left contact of the cam of sequence switch 302 corresponding to cam 413 (1 to 8) to battery through the magnet winding of sequence switch 302 corresponding to switch 410. rlhis sequence switch is thereupon driven from its normal position through position 8 and comes to rest in position 9. With the sequence switch in position 9, the following lamp circuits are closed: ground, the lower contact of the cam of .switch 302 corresponding to cam 415 (7 to 11), lamps' 1 1 to battery; ground, the upper right contact of the cam corresponding' to cam 415 (9 to 11), lamps 3 3 to battery; ground, the upper right contact of the cam corresponding to cam 416 (5 to 11), lamps 6 6 to battery. Lamps 1 1, 3 3 and 6 6 are now lighted displaying the digit 7 on the tens indicator 306.

As will be recalled, the units register relays 320, 322 and 323 were energized in response to the units code of impulses and, therefore, upon the energization of relay 246, a circuit is elfectivefor advancing the sequence switch designated by rectangle 303 similar to switch 410 shown in detail in Fig. 4, from its normal posit-ion. This circuit may be traced from ground through the lowermost armature contact of relay 246, conductor 252, the left armature and front contact of relay 320, the alternate contacts associated with the outer left armature of relay 323, the inner left armature and front contact of relay 322, the outer left armature and back contact of relay 321, conductor 333,

thence, referring to Fig. 4, through the` lower contact of the cam of switch 303 corresponding to cam 414 (1 to 9), to battery through the magnet winding corresponding to the winding of sequence switch 410. The sequence switch now advances from its normal position through position 9 and comes to rest in position 10. With the sequence switch in position 10, the following circuits are closed for the lamps of the units indicator: Ground, the lower contact of the cam of switch 303 corresponding to cam 415 (7 to 11), lamps 1 1 to battery; ground, the upper' right contact of thc cam corresponding to cam 415 (9 to 11), lamps 3 3 to battery; ground, the upper left contact of this cam (10 to 11), lamps 2 2 to battery; ground, the lower right contact of the cam corresponding to cam 416 10 to 11), lamps 4 4 to battery; ground, the upper right contact of this cam (5 to 11), lamps 6 6 to battery; ground, the lower left contact of this cam (10), lamps 5 5 to battery; ground, the upper left contact of this cam (10 to 11), lamps 7 7 to battery. All of the lamps of the units indicator are thus lighted displaying the units digit 8 upon the units indicator 307.

A circuit is also closed at this time from ground, through the inner left armature and contact of switching relay 224, conductor 253, the left arniature and front contact of stations register relay it being recalled that this register reiay was the only stations relay energized in response to the stations code of impulses, thence over conductor 334, through the M stations lamps 329, the outer right armature and contact of relay 328, to battery. rilhc entire designation 3578 M which the B operator recorded uponher vkeyboard 100 is now displayed upon the indicators and from the displayed number, the operator may check the accuracy with which her position apparatus has functioned.

Having ascertained if the line designation has been correctly displayed, the operator may proceed to release the apparatus by depressing the disconnect key 130 associated with her position. Upon the depression of key 130, a circuit is established from battery through the winding of relay 132,

the contact of cam 131 (2 to 17), to ground at key 130. Relay 132, upon energizing in this circuit established a circuit for advancing sequence switch 110 out of position 12 to which it was advanced following the termination of the transmission of code impulses. The circuit of sequence switch 110 may be traced from battery, through the magnet winding of sequence switch 110, contact of cam 133 (12 to 17), the armature and contact of relay 132, the upper left contact of cam 113 (12 to 17), to ground at the lower contact of cam 113. The sequence switch now advances into position 18 i n which position the district selector is restored in the manner fully set forth in the aforesaid patent to F. A. Stearn. It may be noted at this point that when the sender 101 completed the transmission of code impulses for setting the indicators of Fig. 3 it became disassociated from the trunk 104 and the sequence switch 110 was advanced from the selection-beyond position 11 and came to rest in position 12.

As soon as sequence switch 110 leaves position 161/2, the holding circuit previously traced over brush 111 and terminal 107 for relays 124 and 202 is opened at the upper right contact of cam 113 and these relays thereupon release. Relay 124, upon releasing its armatures opens the circuit previously traced for relays 117 and 200, and relay 202, upon releasing, opens the circuits of relays 203 and 208. With relays202 and 208 deenergized, holding ground is removed from conductors 209 and 216, releasing all of: relays fof;-

a`11'df3i-fyv`hifchFare at f the time operated. Upon the* release of' rel" lays 821 ,ancl28-,- the oirou'itf :for sta-tions llamps :3,29 ,is opened and1 theselampsai-e tinguishedr As soonasrelay'QOS releasesiitsarmatures;1

ground is connectedV .at the backcontacts 'of'- itsgarinaturs to conductors 204512055 S206v vand :207-l extending to.; the upper ilef't' "contacts"D of Y Canis oorrespending1 to v'carni 412A4 of' the'4 se.lv

quenoe'f Syri,teldesy associated; with che'f 'incli-V catorsz- Y 'The circuit- ;for .sequence switch-410 corresplnding" to :sequence lswitch 300 gaeso'oif atel wit-lithe' :thousands n indicator1 may'ffo example; -loetraced from liatiteryj,,Lthrough' the magnet WindingI 'of switch 4'10, the 1110-" per-left-C/Iltactofcani L12 :(1210 118),,ioo'n duotor 207 to ground at the intermediate right armature and'-bacl-,eo1taetof relayA4 Singel these Cain cdntaots'rare Closed' norm-al oitioniandthe operator/may then proceed-i i'fshe Wishes, 'to ltest 'lierT positionv with other*` line-- designationsyin the Inanne'r just describel.v A

as hereinbefore desoribelyexcept that'before startingthe test, the: cordless f B operator assigns' -a trunk, such,'-fr: example', asf trunk 104, cysgcerilingl to; partieiilarv ymanual 'o'fc'eAIV and vdirectsthe- A- :operatorEatY suoli' manual? office to onneot-one of hercorol circuits*therev-Y wr 0f jack 140.

WitlLl In response lto '-the recordingof arden sired line designation 'upon .the keyboard 100 5' at therB o-pe'rators position; theline vdesignation becomes displayed" -11- `:the ina'nner previously deso'riloed-upon thetr test :indiea multiple, plugs 135'/ andi 136' andHhet jacks" 137 and 133;l Azci'Cui-t-isnowestallished' and front entact closes a circuit for the out- As che sequence sWiehes-ereachtheir normal positions; the' lighted-lamps of the several,.indeatorsare" extingishedf.; .A llapparatusVeniplojyeol'Y in" mak-inglthe testvhasfno'w' `been restored @to its"- .righe miniature me @61112151 direeelyf 1b forth 111' the aforesaid patenti@ Aysteamji; .www pe'mdf a1 'the iisfajnemffmmiaf-- ice'reeeiyes' a; supervisory signa-l indioating Ithat' She may talk withtiie.Bcofdless op;

emol- The mikingtcireuit,egtendingffrouif f the heafdset l134; at' lie cdroll'e'ssposition fooE .in pea' 110111x the ltip 0131011' '110, ltphefnpp'ey comme" of am' 11e, brehi 10e, jbankj termi; 11111 'th/'uppmfmetme halb-mk ve011-, e101 @1f relay 117, the liep@ lef# windingo Q1 plugye; the-receiver df thfhfadset 134,;

^ Sieeveef plug 135, .Sleeve-rden 1,313L the *Y lreleases relay' 116. Relay 11'6nowreyerses` @me fdischeefefheffefdl 115111 the jaar 140, 'alie'E eire'uit" throng-H the Windingsfof: re"-l u my 141' ana through?efexyiairfggjofrei@ s 1121 is opened adfreiay lcleaisestlie' disg' positionin'themmif pfevidsiydescribed e The',

lay becomes rel'easel. -All apparatus i111" Volved in conducting the test is now in its normal position. The cordless B operator may conduct similar tests with other trunk circuits similar to 104i extending to other manual oiices in the manner previously described.

While in the foregoing, the invention has been described as particularly designed for use in testing apparatus at a cordless B operators position in a machine switching oliice, it will be apparent that the indicators might be employed for displaying line designations before operators in manual offices for the purpose of enabling manual operators 'to complete calls incoming from machine switching olices.

What is claimed is; v

l. In a telephone exchange system, a trunk line, means for impressing current impulses of various characteristics upon the conductors of said trunk line, a primary register, means responsive to said impulses for variably setting said register, a secondary register, means for setting said secondary register in accordance with the setting of said primary register, an indicator positioned to be observable from t-he point where said'impulses are impressed, and means including said secondary register for variably operating said indicator.

2. In a telepho-ne exchange system, a trunk line, means for kimpressing impulses of current differing in polarity and strength upon the conductors of said trunk line, a

primary register, means responsive to saidv impulses for variably setting said register, a secondary register, means for setting said Secondary register in accordance with the setting of said primary register, an indicator positioned to be observable from 'the point where said impulses are impressed, and `means including said secondary register for variably operating said indicator.

3. In a telephone exchange system, a trunk line, means for impressing current impulses of various characteristics upon the conductors of said trunk line, a plurality ot' register relays, means responsive tosaid impulses i''or operating said relays in varying combinations, a secondary register, means controlled by said relays for variably setting said secondary register, an indicator positioned to'be observable from the point where said impulses are impressed, and means including said secondary register for variably operating said indicator.

4,. In a telephone exchange system, a trunk line, means for impressing current impulses of various characteristics upon the conductors of said 'trunk line, a plurality of register relays, means responsive to said impulses for operating said relays in varying combinations, a rotatable switch, means controlled by said relays for variably positioning said switch, an indicator positioned to be observable from the point where said imvariably setting said register, a secondary register, means for setting said secondary register in accordance with the setting of said primary register, an indicator comprising a plurality of groups of signals grouped to form numerals, an actuating circuit for each of said groupsof signals, and means controlled by said secondary register for establishing said circuits in various combinations to display a plurality of diierent numerals.

6. In a telephone exchange system, a trunk line, means Jfor impressing current impulses of various characteristics upon the conductors of said trunk line, a primary register, means responsive to saidiinpulses for variably setting said register, a secondary register, means for setting said secondary register in accordance with the setting of said primary register, an indicator comprising a plurality of groups of signals grouped to form numerals, an actuating circuit for each of said groups of signals, and means controlled by said secondary register forV I establishing said circuits in various combinations to display a plurality of dierent numerals larger in number than the number of said groups of signals.

7 In a telephone exchange system, a trunk line, means for impressing current impulses of various characteristics upon the conductors of said trunk line, a plurality of register relays, means responsive to said impulses for operating' said relays in varying combinations,'a secondary register, means con-V trolled by said relays for variably setting said secondary register, an indicator comprising a plurality of groups of signals, an actuating circuit for each of said groups of signals grouped to form numerals, and means controlled by said secondary register for establishing said circuits in various combinations to display a pluralityy of different numerals.

8. In a telephone exchange system, a trunk line, means for impressing current impulses of various characteristics upon the con-v ductors of said trunk line,"a' plurality of register relays, means responsive to said inipulses for operating said relays in varying combinations, a rotatable switch, means controlled by said relays for variably position-V ing said switch, an indicator comprising a plurality of groups of signals grouped to form numerals, an actuating circuit for each of said groups of signals, and means controlled by said switch. for establishing said circuits .invarious combinations to display a plurality of dilierent numerals.

9. In a telephone exchange system, a trunkregister', means for-setting said secondary,

register in accordance. witlithe' setting- ,Of-

said primary register, anindicator comprisstantialily in the form otthe'ii'uineral eight,

an actuating circuit for cachot saidgroupsjl of. sign-als, and Ameans"controlled by said secondary registerfor establishing said circuits in various combinations to display any one often dierent-iiumerals. A

10.v In `a telephone exchange system, a? trunk line, meansfior impressing current impulses of various: characteristics uponv the, conductorsof saidtrunk line, a plurality of register relays, means responsive to said impulses for operating said relays in varying combinations, a sequence switch register,

. means controlled by said relays for variably ositioriing said sequence switch register, an indicator comprising seven groups of signals arranged substantially in the form of the numeral eight, an actuating circuit for each of said groups of signals, and means controlled by said sequence switch register in the several positions thereof for establishing said circuits in various combinations to display any one of ten different numerals.

1l. In a telephone exchange system, a trunk line, means for impressing current impulses of various characteristics upon the conductors of said trunk line, primary registers, means responsive to said impulses Jfor variably setting said registers in succession, secondary registers, means for setting said secondary registers in accordance with the settings of said primary registers, a plurality of indicators positioned to be observable from the point where said impulses are impressed, and means including said secondary registers for variably operating said indicators.

l2, In a telephone exchange system, a trunk line, means for impressing current impulses of various characteristics upon the conductors of said trunk line, a plurality of groups of register relays, means responsive to said impulses for successively operating the relays of each group in varying combinations, a rotatable switch individual to each group of relays, means controlled by the relays of a group for variably positioning the corresponding switch, an indicator associated with each switch comprising a piurality of groups of signals grouped to form numerals, and an actuating circuit for each of said groups of signals, and means controlled by each of said switches for estabing seven groupsoi` signals arranged sub-v` lishing the circuits or' theJV corresponding indicatorsignals in varioi'is combinations to displayV a plurality 'or different numerals' larger .innuinber thanth'e number of said groups of signals. s s

13.- In a-telephone exchange syster'n,v an' operato'rs,.posit'ion,l a keyboard and air inrpulse sending. device thereat, a trunk line,

means for connectingsai'd operators apparatus' to' said trunk line, means controlled by saidsending device for transmitting iinpulses. over said trunk line in accordance with` the' several digits' of a' line' designation recorded upon said keyboard,` primary registers; meansV responsive to said impulses for variably setting saidregisters inl succes'- sion to' register the digits of said line desi-'gnation-,z a plurality of' secondary registers equal in num-ber' to said primary registers? and operable in accordance with the settings thereof, an indicator associated with' each-K of saidsecondary registersgeach comprising -aI plurality o'f-vgroups of signal'sgrouped to form' numerals and ane actuatingcircuit for each *of saidgroups of signals, and meai'isi controlled by each of said secondary registers for establishing the circuits of the corresponding indicator signals in Various combinations whereby the several digits of said line designation are displayed. i

14. In a telephone exchange system, an operators position having apparatus to be tested comprising a keyboard and a sending device, an indicating device observable from said position, a trunk line extending to said indicating device, means responsive to the operation of certain keys of said keyboard for associating the apparatus of said position with said trunk line, means controlled by said sending device for transmitting impulses over said trunk line in accordance with the several digits of a line designation recorded upon said keyboard, primary registers associated with said indicating device responsive in succession to said impulses, a plurality of secondary registers equal in number to said primary registers and operable in accordance with the settings thereof, and means for displaying upon said indicator the digits of a line designation registered by said secondary registers.

15. In a telephone exchange system, a` plurality of operators positions having apparatus to be tested, the apparatus at each .such position comprising a keyboard and a sending device, an indicating device observable from all of said positions, ka trunk line extending to said indicating device, means responsive to the operation of certain keys of the keyboard of the position for associating the apparatus of said position with said trunk line, means controlled by said sending device for transmitting impulses over said trunk line in accordance with the several digits of a line designation recordedupon said keyboard, primary registers associated with said indicating device responsive in succession to said impulses, a plurality of secondary registers equal in number to said primary registers and operable in accordance with the settings thereof, and means for displaying upon said indicator the digits of a line designation registered by said secondary registers.

16. In a telephone exchange system, an operators position having apparat-us to be tested comprising a keyboard and a sending device, a manual oiiice, a trunk circuit extending from said ofiice to said operators position, means for associating said trunk circuit With said apparatus, an indicating device, means under the control of said key board and sending device for extending a connection from said trunk circuit to said indicating device, means under the control of said sending device for displaying the designation of a line recorded upon said keyboard, an operators head set at said position, means for connecting said set With said trunk circuit for completing a talking connection with said manual office,- and means operable thereupon for releasing said indicator.

' 17. Inatelephone exchange system, an operators position, responsive means at a distant point, an indicator observable from said position controllable by said responsive means, and controlling means at said position for controlling said responsive means to cause the display upon said indicator of any desired line designation.

18. In a. telephone exchange system, an operators position, controlling means at said position, a plurality of trunk circuits outgoing from said position, indicating apparatus at a distant point controllable by said means over certain of said trunk circuits, and an indicator observable from said position controllable by said means over another of said trunk circuits.

In Witness whereof I hereunto subscribe my name this 26th day of December A. D. 1922.

FRANK N. REEVES.

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