US1504295A

US1504295A - Telephone-exchange system

Info

Publication number: US1504295A
Authority: US
Publication date: 1924-08-12
Anticipated expiration: 1941-08-12

Description

Aug. 12, 1924. 1,504,295

S. B. WILLIAMS, JR

rzmrnons EXCHANGE svsriam Filed Dec. 15. 1920 5 Sheets-Sheet 1 N IL 2 O I: S a n SUBGROUP I /nve/1f0r: Jamue/ 5. W/l/Mms Jr? Aug. 12 1924. 1,504,295

5. B. WILLIAM; JR

TELEPHONE EXCHANGE SYSTEM Filed Dec. 15 1920 5 Sheets-Sheet 2 /n vemar: jamae/ 5. MV/iams J Aug. 12, 1924.

5. B. WILLIAMS, JR

TELEPHONE EXCHANGE SYSTEM Filed Dec. 15. 1920 5 Sheets-Sheet 5 "s gns,

lm emor: jamue/ & MY/zkm: Jr:

Aug. 12, 1924. 1,504,295

S. B. WILLIAMS, JR

TELEPHONE EXCHANGE SYSTEM Filed Dec. 15'. 1920 5 Sheets-Sheet 4 //7 vemor: Jamae/ & MY/r'am: J

Aug. 1z 1924. 1,504,295

S. B. WILLIAMS, JR

TELEPHONE EXCHANGE SYSTEM Filed Dec. 15 1920 5 Sheets-Sha 5 /h venfor:

Patented Aug. 12, 1924.

UNITED STATES PATENT OFFICE.

SAMUEL B. WILLIAMS, JR., OF BROOKLYN, NEW YORK, ASSIGNOR TO WESTERN ELEC- THIS COMPANY, INCORPORATED 015 NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Application filed December 15, 1920. Serial No. 480,823.

To aZZ whom it may concern:

Be it known that I. SAMUHL B. IL- LIAMS, Jr., a citizen of the United States, residing at Brooklyn, in the county of Kings, State of New York. have invented and the first directive switch of the chain ofswitches employed toextend connections,

by either a line switch individual to a subscribers line and having access to a group of such directive switches, or by a line finder which is individual to the first directive switch and serves to connect such switch wth a calling one 01 a group of subscribers 1 comprising one-hundred lines.

lines to which the line finder has access. The present invention relates to a switch of the line finder type, and more particularly. to a switch which comprises groups of con necting relays for establishing such conner' tions.

Heretofore, line finders of the relay type have been developed for serving decimal groups of subscribers lines. that is, groups Such line finders employ a group of tens connecting relays and a group of units connecting 1clays' which are individual to a link circuit or trunk line extending to the first directive switch of the system and are energized in different combinations for extending connections from the several lines of the groups to the trunk line.

It is at times desirable to group lines in larger groups. which may contan a nondecimal number of lines, as for example, two-hundred lines or more as is the wellknown practice in systems employing switches of the type shown in the patent to E. B. Craft and J. N. Reynolds No. 1,123,696. issued January 1915. A switch of this type may also be employed for associating ofiice sender equipment with a selected trunk line for controlling the setting of directive switching apparatus and GSJL- cially in oflices in which a sender equipment is assigned to a large group of trunk lines containing a non-decimal number of trunk lines.

A further object of the invention is to provide a switch of the relay type which is capable of serving a large group of subscribers lines containing a non-decimal number of lines.

Another object of theinvention is to provide a switch of the relay type which is capable of serving a large group of trunk lines for extending them to an idle ollice sender equipment. 7

A still further object of the invention is to provide a simple and novel means for multipling the contacts of a. plurality of relays.

One feature of the invention resides in dividing the subscribers lines into connective sections, each comprising a non-decimal number of lines and dividing each section into ten groups of lines each coin rising a non-decimal number of lines and further dividing each group intoa plurality of subgroups each comprising a decimal number of lines. In" thepresent application ea h section com rises two-hundred subscribers lines divide into ten groups of twenty lines each and each group comprising two subgroups often lines each. Each link circuit to which the subscribers lines of a section have access has associated therewith ten group relays a pair of subgroup relays and ten units relays which are provided for establishing connectionsfrom any line of the section to the link circuit. ln'the establishment of a connection from any line of the section, it is therefore necessary to energize a group relay corresponding to particular group of twenty lines in which the calling line is located, a sub-group relay determined by the location of the line. in the first or last ten of each main group and a units relay corresponding to the location of the line in the sub-group.

A further feature of the invention resides in the adaptation of the invention as a district finder switch for associated a sender equipment with the link circuit to whlch a calling line has been extended. The district selector switches in which the link circuits terminate are grouped in frames comprising sixty switches each, two of such frames comprising a connective unit. The one-hundred and twenty switches thus a unit. are dflidei "into twelve gms ten switches each and are further divided into two subgroups of five switches each. A grasp 6 twelve group rel ys, a pair of subgrou relays an five units relays are pro vided for establishing connections from any district selector switch to the ofiice sender equipment. In the establishment of anection it is, therefore, necessary to energize a group e subgroup and a units relay.

A still further feature oi the: invention resides in the provision of a plurality 0t sets of bare conducting elements which may be in the form of rods or wires, which elements serve as passive contacts of a group of relays.

Other features of the invention will be apparent from the following description taken in connection with the accompanying drawing in which Fig. 1 shows a plurality of subscribers lines assigned to the same connective sectiombut located in di'flerent groups of the section together wit-hcertain of the group, suhgrou p and units connecting relays for extending connections fro-m such lines to a link circuit terminating in a district selector switch; Fig. 2 shows the controlling equipment associated with the subscribers lines of Fig. 1 tor controlling the circuits of the line connecting. relays of thcconneetive section. together with a. link circuit allotter switch and finder time alarm switch: Fig. 3 shows the circuits of a district selector switch-towhich the suhscrilo'ers lines may be extended and through which connections may be extended automatically to various districts of the exchange; 4: shows the circuits of a district finder switch for associating an ofl'ice sender, shown die grami-natically in the upper dotted rectangle, with a selected district selector: and Fig. 5 shows a modified circuit arrangement corresponding to Fig. 1. but d thering therefrom through the employment of bare wire multiples serving as multiple passive contacts for the group and subgroup connecting rela st- The figures of the drawing when placed! with Fig. 3- to the right of Fig.- 1, Fig.2 beneath- Fig. 1 and Fig. i loeneath Fig. 3 show so much of the com-plate organization of circuits as is necessary for an LUIIdGP-' standing of the invention. Fig. 5* when sulo stituted for Fig.- l in the above outlined circuit arrangement illustrates the manner in which the modified term of line finder mayhecmploycd in connection with this invent rm,

,lnrFig. 1.; five subscribers lines have been illustrated which it will he assumed are lines Nos: ancee, see and an in the first sn'cl; secol id'gmoups of the same connective For convenience of illustration, these have been diagrammatically shown; but it isto understood that they are of the well-kncnvn type adapted for use in establishing full automatic connections.

The finder alarm switches FA and FA and allotter switches A and A shown in Figs. 2 and 4 are of the well-known step-by-s'tep type. the alarm switches being arranged to he stepped on around to normal position for restoration and the allotter switches being arranged to have no normal position, but to rest normally in such positions so as to allot idle equipment tor use.

The district selector switch, shown in Fig. 3, is of the powerdriven .type shown in the patent to E. 8. Craft and J. N. Reynolds hereinbetore referred to, and is provided with controlling circuits which are more specifically of the type disclosedin Patent. 1,395,977, issued November 1, 1921, to F. A. Steam and F. J. Scudder.

The relay line finder shown in Figs. 1 and 2 comprises, as hereinbetore stated, a group of ten units connecting relays, a pair of subgroup relays and ten group relays. In order to reduce the complexity of the circuit disclosure, only two-of the units relays and two of the group relays have been disclosed. The link circuit to which the line finder is individual is multipled through the armature contacts of all of the units relays, the ten multiples of the link then appearing in the ten sets of armature contacts of each of the sub-group relays. The sulrgroup relays are for this purpose each provided with thirtyone armature contacts.

Ten sets of conductors are connected to the armature contacts of each sub-group relay and are multipled to armature contacts of each of the ten group relays. Only two of the sets of conductors extending from armature contacts of sub-group relay No. 1 to armature contacts of group relays. No. l. and No. 2 have been disclosed. It is to he understood, however. that in a similar man n-er eight other sets of conductors would be employed and that ten sets of conductors would likewise extend from contacts of the No. 2 subgroup relay to armature contacts of all ten group relays in the manner illus trated in connection with line No. 631. The group relays are. for this purpose provided with sixty-one armature contacts. From the armature contacts of the No. 1 group relay, line conductors extend in the manner shown to the substations of twenty subscribers lines. In this case. it has been assumed that the first twenty lines of the group are numbered 601 to 620' inclusive. In a similar manner, lines numbered 621 to 640 are con" nected to armature contacts oi group relay No. 2, etc.

For allotting the connecting relays of a particular line finder for use, a relay such as shown at 103 is provided individual to a link circuit, through the armature contacts of which the energizing circuits of all units,-

subgroup and group relays of the finder to be allotted extend. There are from seventeen to twenty of these relays in each connective section, since every section of two hundred lines has access to from seventeen to twenty link circuits. Each of these relays is thus provided with twenty-four armature contacts. The manner in which the circuits of the various connecting relays are selectively closed by the group, subgi'oup, and units controlling relays of which t ere are ten group, two sub-group and ten units relays, will appear more clearly from the following description. To simplify the drawings, only the group and sub-group relays of two groups of a single connective section, and three of the units controlling relays of the section have been disclosed in Fig. 2.

The finder switch shown in Fig. 4. is similar in construction to that shown in Figs. 1 and 2 except that the six conductor link circuit individual to the allotted office sender is multipled through armature contacts of five units relays and the five multiples are then multipled to live sets of armature contacts of the two sub-grou relays. Twelve group relays are rovided in this instance, each provided with ten sets of armature cont acts, five of the sets being connected to contacts of the No. 1 sub-group relay and five of the sets to the contacts of the No. 2 subgroup relay. Each group relay thus enables connection to ten district selector switches. A sender is in this manner made common to one hundred and twenty district link circuits.

Only so much of the office sender is disclosed in Fig. 4 as is necessary for an understanding of the invention. For a complete disclosure of the oflice sender of the type used in setting up a connection, refererzipe is made to the aforesaid Patent 1,395,- 9

Inasmuch as this invention is not concerned with the extension of a connection beyond the district selector switch, the other selector switches which are necessary for establishing a complete connection, have not been disclosed herein. Such switches may be of the type disclosed and fully described in the aforesaid Patent. 1,305,977.

The general mode of operation and the apparatus employed having now been briefly described, it is believed that a clearer understanding of the invention may be had from a detailed description of the manner of extending a connection from a calling line to the district selector switch shown in Fig. 3. For the purpose of this description. it will be assumed that the calling subscriber whose directory number is 601 initiates a call. Upon the removal of the receiver from its switchhook, a circuit is established for line relay 200 which may be traced from grounded battery, through the upper winding of this relay, the inner armature and back contact of cut-oil relay 201, thence over the line loop of subscribers line No. 601 and to ground at the outer arn'iature and back contact of cut-oil relay 201. Relay 200 upon energizing in this circuit. establishes a circuit for the units controlling relay 202 and for the sub-group relay 203 which may be traced from grounded battery, throughthe winding of r lay 202, conductor 204, the armature and front contacts of line relay 200, conductor 205, the winding of sub-group relay 203 and thence to ground at the let'thand armature and back contact of relay 20b. Relays 202 and 203 become energized in this circuit, the units relay 202 connecting ground to the units conduct-or 207 for de termining the particular units connecting relay which is to be operated, and the subgroup relay 203 determining the particular subgroup connecting relay which is to be operated. Since as has been assumed, the number of the calling line is 601, the calling line is therefore located in the first sub group of the first group of subscribers lines and, therefore, the operation of the subgroup relay 203 will determine the operation of the sub-group connecting relay 100 corre sponding to the location of the calling line.

Had the number of the calling line been 611, then line relay 247 individual to such calling line would have been energized, establishing a circuit through the winding of units relay 202, the Winding of sub-group relay 208 and thence toground at the righthand armature and back contact of relay 206. In this case, sub-group relay 208 would prepare a circuit for the sub-group connecting relay 101.

relay 203 upon energizing, connects ground through its left-hand armature and front contact to conductor 209 for preparing a circuit for the sub-group connecting relay 100 and at its right-hand armature and front contact closes a circuit which may be traced from grounded battery through the right-hand winding of group relay 210, the right-hand armature and front contact of relay 203, conductor 211, the lower armature and back contact of relay 212 and thence to ground at the left-hand armature and back contact of relay 213. Relay 210 energizes in this circuit and at its righthand armature and front contact connects ground to the conductor 214 to prepare a circuit for the group connecting relay 102 corresponding to the group of twenty lines of the connective section in which the calling line is located. In the case assumed. the calling line is located in the first group of the connective section. It is to be noted in this connection that the group relay 210 will become operated when either subgroup relays 203 or 208 are operated.

Sub-group relay 203 at its right-hand ar mature and back contact opens a normally closed chain circuit which extends from grounded battery through the winding of finder alarm relay 216, conductor 217, the right-hand armatures and back contacts of all unenergized sub-group relays of the connective section, conductor 211. the lower armature and back contact of relay 212 and thence to ground at the left-hand armature and back contact of relay 213. Upon the opening of this circuit, relay 216 deenergizes and at its armature and back contact closes a circuit extending from ground through brush 237 the normal contact upon which it is resting and through the winding of relay 218 to battery and ground. Relay 218 energizes in this circuit and at its lowermost armature and front contact establishes a locking circuit for itself, independent of brush 237. At its uppermost armature and front contact relay 218 closes a circuit from interrupter 219 through the winding of stepping magnet 220 to battery and ground. Under the influence of the interrupter, mag-- net 220 advances the brushes of the alarm switch FA step by step. If at the time brush 221 engages terminal 222. the subgroup relay 203 is still energized denoting that the connection has not proceeded as it should then a circuit is completed for alarm relay 223 which may be traced from grounded battery. through the winding of relay 223. terminal 222, brush 221 and thence to ground at the intermediate armature and front contact of relay 218. The terminal in the bank of; switch FA to which the winding of alarm relay 223 is connected, as for example terminal 222. is so selected as to allow suflicient time to permit a connection to be completed from a suhscribers line to a district circuit. This time might. for example, be two minutes and would be determined by the time required for the interrupter 219 to advance brush 221 to terminal 222.

Alarm relay 223 upon energizing establishes a circuit for a selector alarm device (not shown) and at its upper armature and front contact closes a circuit through the stepping magnet 224 of the district selector allotter A for allotting another district selector switch and associated line finder in place of the district selector and associated line finder which have failed to function properly. The circuit of stepping magnet 224 may be traced from grounded battery, through the winding armature and contact of magnet 224 and thence to ground at the upper armature and front contact of alarm relay 223. To insure that magnet 224 will not become deenergized until after it has advanced switch brush 230 a full step relay 235 is provided. This relay energizes in parallel with the magnet 224 through the armature contact of magnet 224, and at its armature contact closes an energizing circuit for magnet 224 which is independent of its initial circuit. \Vhen the armature of magnet 224 approaches the end of its stroke the circuit of relay 235 is opened and 235 upon deenergizing opens the auxiliary circuit of magnet 224. Should the connection be made before the alarm switch FA advances brush 221 into contact with terminal 222, then the holding circuit of relay 218 will be opened by the reenergization of relay 216, and relay 218 upon deenergizing closes a circuit for driving the brushes of the switch into their normal position, which circuit may be traced from grounded battery, through the winding. armature and contact of stepping magnet 220, brush 225, the olf normal terminals of the bank with which it is associated and thence to ground at the intermediate armature and back contact of relay 218. Under the influence of its own armature contacts magnet 220 advances the brushes of the switch until they reach their normal position, when the driving circuit of magnet 220 is opened at brush 225.

At the time group relay 210 energized, the normally closed chain circuit extending from grounded battery, through the winding of relay 226. conductor 227, the inner left-hand arniatures and hack contacts of all group relays of the connective section and thence to ground through the winding of relay 212 and the left-hand armature and back contact of relay 213 is opened at the inner left-hand armature and back contact of group relay 210, and if the allotted line finder fails to function within a predeter mined interval to extend the calling line to the allotted district selector switch, the relay 226 becomes instrumental in operating the time measure alarm switch in the manner previously described for operating a finder alarm signal and for allotting another line finder for the use of the calling subscriber. It is to be noted that the circuit of alarm relay 226 is normally established through the winding of relay 212, but since the winding of relay 226 is of high resistance, only relay 226 is normally maintained energized in this circuit.

At its inner left-hand armature and front contact, group relay 21.0 establishes a looking circuit for itself extending from grounded battery, through its left-hand winding, inner left-hand armature and front contact, conductor 228, the inner lefthand armatures and back contacts of all other group relays of the connective section and thence to ground through the winding of relay 212 and the left-hand armature and back contact of relay 213. Relay 212 energizes in this circuit and at its upper armature and front contact closes a circuit for the slow-to-release relay 229. Relay 212 at its lower armature and back contact opens the initial energizing circuits of all group relays of the connective section and at its lower armature and front contact closes a circuit extending in parallel branches through the outer left-hand armatures and back contacts of all group relays of the connective section through the windings of all relays corresponding to rela 206 to grounded battery. There is provi ed a relay corresponding to relay 206 for each group of the connective section. These relays all become energized in the circuit previously traced With the exception of relay 206 of the group in which the calling line is located, and at their armature contacts, open the circuits extending through the corresponding sub-group relays for preventing the simultaneous operation of other subgroup relays should other calling subscribers in the same connective section initiate calls at this time. It is to be noted that relay 206 does not become energized at this time since its circuit is opened at the outer left -hand armature and back contact of relay 210 and, therefore, the circuit of the subgroup relay 203 is maintained.

Rela 229 upon energizing, closes a circuit for re ay 103 of the alloted line finder, which may be traced from grounded battery through the winding of relay 103, the outer right-hand armature and back contact of relay 104, conductor 105, the No. 1 contact and brush 230 of the finder allotter switch, the right-hand armature and back contact of relay 213 and thence to ground at the armature and front contact of relay 229. Relay 103 upon energizing, establishes a lockin circuit for itself extending from grounced battery through its winding, its inner right-hand armature and front contact, conductor 106, Winding of relay 213 and then to ground at the armature and front contact of relay 229. Relay 213, however, does not energize in this circuit since its winding is shunted over the circuit previously traced by way of conductor 105 and the outer ri ht-hand armature and back contact of re ay 104. Relay 103 at its lefthand armatures and front contacts extends all of the conductors leading from the armature contacts of all of the group controlling relays of the connective section, the armature contacts of all sub-group controlling relays of the connective section and of the units relays of the connective section to the respective windings of the group, sub-group and units connectin line finder switch. or convenience of illustration only the conductors extending from contacts of the first and second group relays and the first and second units relays have been shown, but it is to be understood that relay 103 would be equipped relays of the alloted group relays 202, 203 and 210 and, there-f fore, only units connecting relay 107, a subgroup connecting relay 100 and grou connecting relay 102 will be energized. Relay 107 upon energizing, closes a locking circuit for itself extending from grounded battery through its right-hand armature and front contact, conductor 108 and thence to ground at the outer right-hand armature and front contact of relay 103. In a similar manner relay 100 closes a locking circuit for itself extending over its upper armature and front contact andto ground over conductor 108, and relay 102 establishes a locking circuit over its right-hand armature and front contact, conductor 109 and to ground at the outer right-hand armature of relay 103.

Upon the energization of

relays

107, 100 and 102, a connecting circuit is established over the heavy conductors from the tip and ring conductors of the calling line to the trunk conductors 110 and 111 extending to the district selector switch Fig. 3. A circuit is also established for the cut-off relay 201 of the calling line, which may be traced from ground through the windings of cut-off relay 201, conductor 112, armature contact 113 of group relay 102, conductor 114, armature contact 115 of the subroup relay 100, conductor 116, conductor 11 the innermost left-hand armature and front contact of units relay 107, sleeve conductor 118 01 the selected trunk circuit, the lower 'Ijeft-hand contact of sequence switch cam 302 1 to 2%), the normally closed contacts associated with the right-hand armature of relay, 303 and thence to grounded battery through the lefthand windin of sleeve relay 304 of the selected district selector switch 350. Relay 201 opens the circuit of line relay 200 which in turn opens the previously traced circuit throu h the windings of the units relay 202 and t e sub-grou relay 203. Relay 304 energizes and at its outer left-hand arma ture and front contact closes a circuit for relay 104 extending from grounded battery over conductor 119 and thence to ground at the armature contact of relay 304.

Relay 104 upon energizing in this circuit closes a new locking circuit for

relays

107, 100 and 102 at its inner right-hand armature and front contact. At its outer right-- hand armature and back contact, relay 104 0 n'st e shunt around the windin of relay 2 "allotter switch, w iereupon rlliiy Q13beboines energized. Relay 213 upon cilia gi'zling, opensat the back contact of its left handarinature the previously traced circuit entending throu h the windings of "and group re ay 210 and at the fifqi? eonaet of this armature establishes a hircuit hrough the stepping rnagnet 224 ogtheallotter switch for'a'dvancing the al- 1 ttlreselect another line finder for tst'abishing any subsequent call whichay he initiated in this connective The-deeriergiza'tion of relay 212 opens paraflcl circuits which have held the og sears ee reisr ndins t relay 6 ergi ell? restoresthe circuit previously traced lowermost armature arid back cdnta t an'dopensat its up er armature and "t iohtactthe previousy traced circuit oftlfesloyv-to-r'elease relay 229 which, after an whichi sufficient to permit the svciitphto advance; opens the prel is t ias fl's r si sh relay R hi 2 3 thereupon dee'nergizes and at its 1e d armature contact restores ground conrfec'tionlo the circuits previously traced thriiughrelays 216 muses. control circuits asseciated with the connectivesectron infwhich the calling line is located are normal condition and a second connettion initiated in 'th'e se'lective section may be eiitendedto another distric't'selector Swlteh'ini'the manner hereinbefore described. the deenergization o'frelay 229, the locki circuit previously traced through the of relay 103 is opened and relay 103 deenergizes to disconnect the control conductors from the windings of the connecting relays a r id at its outer right-hand armature and trout contact opens the previously traced locking circuits of connecting

relays

107, 100 and 102, but since relay 104 is at this time energized, these relays are now maintaind energized over the inner right-hand armature and front contact of relay 104.

Relay 104 upon its energization also extends a circuit from the conductor 105 through the outer right-hand armature and front contact of relay 104 to the conductor 231 fior transferring the finder starting cir unit from relay 103 associated with the first line finder of the group to relay 32 associated with the second line tinder of the group, so that in case a second connection is initiated in the connective sec tion after the first line finder has been taken for use and before the brush 230 of the finder allotter switchhas moved to its second position, such second connection will start the second line finder. At its inner left-hand armature and front contact relay 104 closes a circuit through a units and a sub-group relay corresponding to the location of th selected district selector in the group of dis trict selectors which are assigned for ex" tending calls from the particular connec tive section in which the calling line is located. This circuit may be traced from grounded battery through the winding of the units controlling relay 400, conductor 401 conductor 402, the left-hand contacts of sequence switch cam 305 (1), conductor 306. theinner left-hand armature and front contact of relay 104, conductor 233, the winding of sub-group relay 451 and thence to ground at the left-hand armature and back contact of relay 452.

Sub-group relay 451 upon energizing establishes a circuit extending from grounded batter through the right-hand winding of group relay 403, right-hand armature and front contact of relay 451, the lower armature and back contact of relay 404 and thence to ground at the left-hand armature and back contact of relay 405. Relay 403 energizes in this circuit and at its inner lefthand armature and front contact establishes a'locking circuit for itself extending through the normally closed inner left-hand armatures and back contacts of all other group relays associated with the group of district selector switches, through the winding of relay 404 and to ground at the leftliand armature and back contact of relay 405. Re- 19,5404 energizes in this circuit and closes a GIl CHlt for the slow-to-release relay 406 and at its lower armature and back contact opens the previously traded energizing circuit of relay 403. The group relay 403, the subgroup relay 451 and the units relay 400 connect ground to conductors extending to lefthand armature contacts of all allotting re lays corresponding to relay 407.

"If upon the energizartion of either the subgroup relay 451 or the group relay 403 the allotted link finder does not function to extend the connection from the selected dis trict selector switch to a sender equipment 420 such as shown in the upper small dotted rectangle in F i 4 within a specified time, the alarm switc FA functions in themanner previously described in connection with the alarm switch FA disclosed in Fig. 2 to give an alarm and to adrance the brush 409 of the district finder allotter A to select another district finder switch.

Upon the energization of slow-to-release rela 406, a circuit'is established for relay 40'? of t e allotted finder switch which may be traced from grounded battery through the winding of relay 407, the outer left-hand armature and back contact of relay 410, conductor 411, brush 409 of the allotter switch,

the right-hand armature and back contact 1 of relay 405 and thence to ground at the armature and front contact of relay 406. Relay 407 energizes in this Circuit and at its ri ht-hand armature and front contact closes a locking circuit for itself extending over conductor 412 through the Winding of relay 405 and to ground at the armature and front contact of relay 406. Relay 405, however, does not energize in this locking circuit, since its winding is shunted by the circuit previously traced extending through the outer left-hand armature and back contact of relay 410. Relay 407 at its left-hand armature contacts extends the conductors grounded at the contacts of controlling

relays

400, 451 and 403, through the windings of corresponding connecting relays. Under the assumption that the No. 1 district selector switch has been taken for use and since the N o. 1 district selector is the first selector in the first sub-group of the first group of selectors, a circuit is established at this time for the No. 1 connecting relay 413 extending from grounded battery through the winding of relay 413, the innermost left-hand armature and front contact of relay 407 and thence to ground at the armatuic and front contact of the units controlling relay 400. A circuit is also established for the No. 1 sub-group relay 414, which may be traced from grounded battery, through the winding of relay 414, armature contact 415 of relay 407 and thence to ground at the lefthand armature and front contact of subgroup controlling relay 451. A circuit is also established for the No. 1 group relay 416, which may be traced from grounded battery through the winding of relay 416, armature contact 417 of relay 407 and thence to ground at the right-hand armature and front contact of group controlling relay 403. Relays 413, 414 and 416 upon energizing in the circuits previously traced, close locking circuits for themselves extending to the conductor 418 and to ground at the outer left-hand armature and front contact of relay 407. It is to be noted at this time that relay 407 is in practice provided with as many sets of left-hand armaturecontacts as there are units, sub-group and group relays in the connective section, in this particular instance, twelve sets of contacts for controlling the circuits of the group relays, two sets of contacts for controlling the circuits of the sub-group relays and five sets of contacts for controlling the circuits of the units relays.

l pon the cnergizatiou i relays 413, 414 and 416 the link circuit 419 terminating in the ol'lice sender 420 becomes extended to the selected district selector switch. In the dis closure of Fig. 4 only a portion of the contacts of the Sll -gTOllJ and group relays have be n disclosed an only two of the five units relays and two of the twelve group relays have been illustrated. It is to be understood. however, that each sub-group relay is provided with live sets of armature contacts of six contacts each and that each rou relay is provided with ten sets of armature contacts of live sets each, five of the sets of arinul urc contacts of each group relay being multipled as illustrated through armature contacts of subgroup relay 414 and the remaining five sets of armature contacts of each group relay being multipled through the armature contacts of the No. 2 sub-group relay 421.

If the selected district selector had been the No. 6 selector, the No. 2 sub-group controlling relay 422 would have been energized in series with the No. 1 units controlling relay 400 in the manner previously described in connection with relays 451 and 400 and the link circuit 419 would have been connected through contacts of the No. 1 units relay 413, of the No. 2 sub-group relay 421 and of the No. 1, group relay 416.

Following the energization of connecting; relays 413, 414 and 416, a rircnit is eslulr lishcdfrmn grounded haltery through the windings ol' relays 410 and 422, in parallel. the contacts of sequence switch cam 424, (l l which sequence switch rum is associated with the register control circuit o l the ollicu Sender as fully disclosed in the aforesaid Patent 1,305,977, thence over lest conductor 425 of the link circuit 419, armature con tact 426 of the units controlling relay 413. armature contact 427 of sub-group relay 414, armature contact 4528 of group relay 416, conductor 429, the lower contacts of sequence switch cam 308 (1 to 2), conductor 309 and thence to ground at the outer lefthand armature of relay 104.

Relay 410 upon energizing, closes a locking circuit for itself extending through its inner left-hand armature and front contact to the test conductor 425 independently of the contacts of sequence switch cam 424 and at its outer left-hand armature and front contact extends the starting conductor 411 to the starting conductor 449 of the second district selector tinder switch. At the back contact of its outer lefthand armature, relay 410 opens the shunt circuit previously traced around the winding of unlay 405, whereupon relay 405 becomesenergized to open at the back contact of its left-hand armature the circuit previously traced through the windings of relays 404 and 403. Relay 404 upon deenergizing opens the circuit previously traced through the Winding of slow-to-release relay 400. After an in terval, relay 406 retracts its armature open.- ing the previously traced locking circuit extending through the windings of relays 40: and 405, but not until after relay 405 re mains energized for a sufficient interval to advance the brush 409 of the allotter A one step by means of the stepping circuit which may be traced from grounded. battery, through the winding and armature and contact of stepping magnet 430 and the lefthand armature and front contact of relay 465. To insure that the stepping: magnet 433 will remain energized for a sutiicient time to advance the brush 409 a ionipiete step. the auxiliary relay 431 is energized over a circuit extending through its winding, the armature contact of stepping magi net 430 to ground at the left-hand armature and front contact of relay 405 and at its armature and front Contact (loses a circuit or the magnet 43(l whi h is independent of the contacts of relay 405. Relay 4%} thus remains energized until stepping. magnet 430 has fully attracted its armature and ha thereby moved the stepping pawl which is attached to (he armature to such an extent as to engage behind the Elitt tooth oi the stepping ratchet oi the alloiter switch.

Upon the energi-zation of relay 423. a circuit is established which may he traced from ground through the upper armature and trout contact oi relay 423, the upper contact of sequence switch earn 432, conductor 133, thence through armature contacts of

relays

413, 4,14 and 41th conductor 31H), the lower contacts of sequence switch cam 311 and thence to ground and. battery through the right-hand winding of line relay 312 of the selected district selector switch. Belay 312 upon energizing closes a circuit for udvane ing the sequence switch 300 of the district selector out of position 1 and into position 2, which circuit may be traced from grounded battery, through the magnet winding oi sequence switch 300, the lower right-hand contact of sequence switch cam 313, the inner left-hand armature and front contact of relay 312 and thence to ground at the lower left-hand contact of sequence cam 314 (1 to 6). As soon as the sequence switch leaves position 1, the circuit previously traced over the left-hand contacts of cam 305 and through the windings of units control relay 400 and sub-group control relay 451 is opened and these relays become deenergized. Relays 400 and 451 become deenergizcd before relays 404 and 405 of the allotter have restored the previously traced starting circuits, so that a second district finder switch is not started to connect the sender 420 with the same district selector.

As soon as sequence switch 300 leaves position 1, the circuit previously traced through the winding of relay 312 is opened at the lower contact of sequence switch cam 311 and relay 312 thereupon deenergizes. A circuit is now established for driving sequence switch 300 out of position 2 and into position 3, which circuit may be traced from grounded battery, through the magnet winding of the sequence switch, the lower lefthand contact of sequence switch cam 313, the inner left-hand armature and back con tact of relay 312 and thence to ground at the lower left-hand contact of sequence switch cam 314.

Upon the energization of connecting relays 413 414 and 41-6, a dialing circuit is established. between the calling subscribcW-s line and the windings of the stepping relay 434 of the registers associated with the oiiice sender, which circuit may be traced from grounded battery, through the righthandwinding of relay 434, armature contacts of relays 413, 414 and 416, conductor 31:"), the lower contacts of sequence switch can 316, trunk conductor 110, armature contacts of connecting relays 107. 100 and 92, thence over the calling suhscrihers line loop. through armature contacts of relays 102. i041 and 107, trunk conductor 111, the upper contacts of sequence switch earn 317, conductor 343, armature contacts of connecting relays 416, 414 and 413 and thence to ground through the left-hand winding of register stepping relay 434. The calling subscriber receives a. dialing signal over this circuit in the manner described in the aforesaid Patent 1,395,977 and then proceeds to set the registers of the sender as fully set forth in said application.

With the sequence switch 300 of the district selector in position 3 and with the connecting relays 413, 414 and 416 energined, a fundamental circuit, is extended from the right-hand winding of relay 312 of the district selector switch through the winding of stepping relay 435 of the oflicc seilfilil 420 which may be traced from grounded battery, through the right-hand winding of nelay 81-2, the left-hand contacts of sequence switch cam 321, conductor 320, armature contacts of connecting relays 416, M4 and 413, the windings of sender stepping relay 435, the armature and back contact of the O counting relay 436 and thence to ground through the upper righthand and the lower left-hand contacts of sequence switch cam 437 associated with the office sender 420. The setting of the district selector switch proceeds in the manner fully described in the aforesaid Patent 1,395,977, following which the sequence switch moves into posit-ion 10. With the sequence switch in position 10 relay 312 is held energized over a circuit which may be traced through its left-hand winding, the left-hand con tacts of sequence switch cam 331, the lower right-hand and upper left-hand contacts of earn 332 and to ground at the inner left hand armature and frontcontact of relay 319. In position 10 the setting of the incomin and final selector switches (not shown proceeds in the well known manner.

when units selections has been completed, the advanc relay 438 of the oilice sender becomes energized and opens the circuit of relay 319 of the district selector switch to advance the sequence switch 300 out of position 10, in which position it stands during the setting of incoming and final selector switches, into position 11. The circuit over which relay 319 is maintained energized through position 10 of sequence switch 300 may be traced from grounded battery through the winding of relay 319, the upper left-hand contact of sequence switch cam 311, conductor 310, thence through armature contacts of connectin ielays 410, 414 and 413, conductor 433 and thence to ground at the lower contact of scrpience. switch cam 432. to 18). The deenergization oi relay 319 opens the circuit of relay 312 at its inner lefthand armature and front contact and relay 312 upon deenergizing causes the advance of sequence switch 300 out of position 10 and into position 11.

As soon as sequence switch 300 leaves position 10%, the dialling conductors 315 and 318 are disconnected from trunk conductors 110 and 111 at the contacts of sequence switch cams 316 and. 317 and the registers of the ethos sender 420 are thereupon restored to normal position. With sequence switch 300 of th district selector 350 in position 11 and the sequence switch of the sender in position 16 into which position it was advanced following the units selection movement of the final selector switch. the fundamental circuit is again established between the office sender 420 and the district selector for advancing the sequence switch of the district selector through its several talking selection positions in th manner described in the aforesaid Patent 1395977. When the talking selection is completed, which will be assumed to be position 13, the talking circuit between the calling subscriber and the called subscriber is extended over the upper contacts of sequence switch cam 322 and the lower contacts of cam 323 and the

brushes

324 and 325 of the district selector switch and thence in the well-known manner to the line of the called subscriber.

During the establishment of the connection. relay 104 is maintained energized to maintain connecting

relays

102, 100 and 107 energized. over a circuit which may be traced from grounded battery, through the winding of relay 104, conductor 119, the upper right-hand contact of sequence switch cam 326 (2 to 18%) and thence to ground at sequence switch cam 327.

Up to the time that the sequence switch of the district selector advances out of position 11 for talking selection, relays 423 and 410 are maintained energized over conductor 425. the armature contacts of connecting relays 413. 414 and 416, conductor 429, through the lower right-hand contact of sequence switch cam 326 2 to 11), and to ground at sequence switch cam 32?, and during talking selection after sequence switch leaves position 11. these relays are maintainbd energized over a new locking circuit extending from conductor 429 through the lower right-hand. and upper left-hand contacts of sequence switch earn 308, the outer left-hand armature and front contact of relay 312 and thence to ground at the lower contacts of sequence switch cam 328. As soon as talkingselection is completed and relay 312 deenergizes, this latter locking circuit is opened and relays 410 and 423 become deenergized. The deenergization of relay 423 opens a branch of the locking circuits of relays 416, 414 and 413, which may be traced over conductor 439 to ground at the upper armature and front contact of relay 423, and connecting relays 413, 414 and 410 now deenergize disassociating the sender 420 from the district selector 350. The circuits of the sender are now restored to normal position and are available for establishing other connections.

During the time that conversation is tale ing place between the calling subscriber and the called subscriber, supervisory relay 330 is maintained energized over trunk conductors 110 and 111 and the calling subscribers line loop and at its armature contacts maintains the relay 303 energized, thereby maintaining an energizing circuit for the sleeve relay 304, which may be traced from the sleeve conductor 118 through the upper lefthand contact of sequence switch cam 302, (1?; to 16) the alternate contacts of the right-hand armature of relay 303 and thence to ground and battery through the left-hand winding of relay 304. Following the completion of the conversation between the subscribers, relay 330 opens the circuit of relay 303 which upon deenergizing initiates the release of the established connection. The release of the connection proceeds in the man ner fully set forth in the Patent 1,395,977. and since the circuits involved therein are not of the essence of this invention, the description of the method of releasing the connection is not considered necessary. As soon as the district selector switch is restored to its normal position, the sequence switch 300 is advanced into normal position and upon leaving position 18%; opens the previously traced holding circuit of relay 104, which thereupon deenergizes, opening the locking circuits of connecting

relays

102, 100 and 107. These latter relays upon. dccnergizing open the previously traced cir cnit extending from the line of the calling subscriber to the trunk conductors 110, 111 and 118 terminating in the district selector 350. All of the apparatus which was employed in establishing the connection is now in normal condition.

In F 5, a modified arrangement oi the group and sub-group connecting relays is disclosed. This circuit arrangement is de signed to be employed in the place of the ill twenty sets of contact pins 52 circuits shown in Fig. 1 and since the modilied arrangement involves only the group and subgroup connecting relays, the remaining portions of the circuits which are identical with similar circuits in Fig. 1 have been identified by the same reference numerals as employed to designate the same elements in Fig. 1. The modified portions of the circuit have been identified by reference numerals corresponding to the nu) merals applied to similar elements of F1 1 but with the hundreds digit of suc i. numerals changed from 1 to 5.

The line finder switch oi Fig. 5 comprises ten units relays corresponding to relay 107, only two of which are disclosed, ten group relays corresponding to relay 502 and two subgroup relays 500 and 501. 'ihe'group and subgroup relays are mounted beneath a frame 525 and are each provided with an armature adapted to operate a rod vertically slidable in the frame 525. Each rod such as the rod 526 associated with the group relay 502 is provided with 3 each set comprising three pins, the sets being divided into two sections of ten sets each. The contact pinsof each set are connected respectively to the tip, ring and sleeve conductors of a subscribers line. Thus, each group relay controls connections to twenty subscribers lines.

For cooperation with the several sets of pins on the slidable rods, twenty sets of 3 conducting elements 528 are insulatedly supported on the frame 525 in any suitable manner. The conducting elements may be in the form of bare wires or rods 01' in any other suitable form, and are entirely free or electrically isolated Erom all wiring or cable connections.

The slidable rods 529 and 530 which are associated with the subgroup relays 500 and 501 respectively are also each provided with twenty sets of contact pins for cooperation with the conducting elements 528. The lower ten sets of pins on rod 529 and the upper ten sets of pins on rod 530 are shown multipled together, the No. 1 set of pins on each rod being connected to the armature contacts of the No. 1 units connecting relay 107, the No. 2 set of pins to the armature contacts of the No. 2 units relay, etc. The upper ten sets of pins on rod 529 and the lower ten sets of plus on rod 530 are blank and serve no useful purpose and may. if desired, be entirely omitted.

From the foregoing description, it will be apparent that if subgroup relay 500 is energized, only the lower ten sets of conducting elements will be connected to the armature contacts of the ten units relays and that a connection may be established with only the ten subscribers lines which have been assigned to the first sub-group of each of the ten groups of lines in the connective section, and only one of the lower sets of elements will be rendered effective depending upon which of the units relays is energized at the time. Thus in the case previously assumed, it the calling line No. 601 has initiated the call, the No. 1 units relay 107, the No. 1 subgroup relay 500 and the No. 1 group relay No. 502 will be energized and the calling line will thus be extended over the lowermost set of conducting elements 528 through the No. 1 set of pins on group rod 529 and thence through the left hand armature contact of units relay 107 to the conductors 110, 111 and 118 of the link circuit. Had the number of the calling line been 631 then the No. 1 units relay, the No. 2 subgroup relay and the No. 2 group relay would have been energized and the connection extended from the subscribefis line to the second set of pins on the upper portion of rod 531, the second set of conducting elements 528 in the upper ten sets of elements, the second set of pins on the subgroup relay rod 530 and thence to the trunk conductors 110, 111 and 118 through the armature contacts of units relay 107.

The allotting relays may also be assembled in a similar manner as disclosed in Fig. 5 instead of connecting the units, subgroup, and group controlling conductors, as, tor example,

conductors

207, 209 and 214 to a cable multipled to the armature contacts of each allotting relay of each link circuit of the group, as shown in Fig. 1. These conductors are connected to bare conducting elements which serve as passive contacts or all of the allotting relays. The bare conductors, such as shown at 540, may be insulatedly supported in any suitable manner in the frame 541. The allotting relays for the several link circuits are supported beneath the frame 541 and each controls a rod slidable in the frame. Each rod is provided with a plurality of pins 542 for contact respectively with the several bare conductors, in the case assumed twenty-four. Ten of these pins are connected to the windings ot the ten units connecting relays, two to the windings of the two subgroup connecting relays, ten to the windings of the ten group relays, and the remaining two pins are employed one in the locking circuit of the respective allotting relay and the other in the locking circuits of the connecting relays.

Hy thus providing bare conducting elements as passive contacts for the group and subgroup connecting relays and as passive contacts for the allotting relays, the number of relay contact elements individual to each relay is reduced by half and the necessity for soldering multiple conductors to contact elements of each relay is thus eliminated. In this manner the labor entailed in the assembling of the switch is very greatly relilo duced and the cost of the switch materially decreased. In the assembling of the group and subgroup relays no connections are required to the conducting elements and in the assembly of the allotting relays only one connection is made to each conducting element. It will, of course, be evident to one skilled in the art that this inventive idea is applicable to any switching system in which it is necessary to multiple the conductors of a cable to the armature contacts of a plurality of relays, and the application of the invention is therefore to be understood as limited only by the scope of the annexed claims.

While the invention has been disclosed as applied to connective sections containing 200 lines, it will be apparent that larger connective sections may be served in a similar manner by providing additional subgroup relays. Thus, if the subscribers lines are divided into connective sections of 300 lines each, three subgroup controlling relays and three corresponding subgroup connecting relays Will be provided.

What is claimed is:

1. In a telephone exchange system, a plurality of lines arranged in connective sections, the lines of each of said sections being divided into a plurality of groups and each of said groups being further divided into a plurality of subgroups, a link circuit, and means comprising a plurality of relays each individual to one of said groups of lines, a plurality of relays each individual to a particular subgroup of all of said groups and a plurality of relays each individual to a particular line in all of said subgroups for establishing connections between said lines and said link circuit.

2. In a telephone exchange system, a plurality of lines arranged in non-decimal connective sections, the lines of each of said sections being divided into a plurality of groups and each of said groups being further divided into a plurality of subgroups, a link circuit. and means comprising a plurality of relays each individual to one of said groups of lines, a plurality of relays each individual to a particular subgroup of all of said groups and a plurality of relays each individual to a particular line in all of said subgroups for establishing connections between said lines and said link circuit.

3. In a telephone exchange system, a plurality of lines arranged in non-decimal connective sections, the lines of each of said sections being divided decadally into Oups each comprising anon-decimal num er of lines and each of said groups being further divided into a plurality of subgroups each comprising a decade of lines, a link circuit, and means comprising a plurality of relays each individual to one of said groups of 7 lines, a plurality of relays each individual to a particular subgroup of all of said groups, and a plurality ofrelays each individual to a particular line in all of said subgroups for establishing connections between said lines and said link circuit.

4. In a telephone exchange system, a plurality of lines arranged in non-decimal connective sections, the lines of each of said sections being divided decadally into groups each comprising a non-decimal number of lines and each of said groups being further divided into a plurality of subgroups each comprising a decade of lines, a link circuit, a group of ten relays, each individual to one of said groups of lines, a pair of relays each individual to a particular subgroup of all of said groups, a group of ten units relays each individual to a particular line in all of said subgroups, and means comprising one each of said group, subgroup, and units relays for establishing a connection between one of said lines and said link circuit.

5. In a telephone exchange system, a plurality of lines arranged in non-decimal connective sections, the lines of each of said sections being divided decadally into groups each comprising a non-decimal number of lines and each of said groups being further divided into a plurality of subgroups each comprising a decade of lines, a link circuit, means comprising a plurality of connecting relays each individual to one of said groups of lines, a plurality of relays each individual to a particular subgroup of all of said groups and a plurality of relays each individual to a particular line in all of said subgroups for extending connections from said lines to said link circuit, a plurality of group, subgroup, and units controlling relays, and means operative upon the initiation of a call in a connective section to operate the group, subgroup, and units controlling relays corresponding to the location of said line in the section for controlling corresponding connecting relays.

6. In a telephone exchange system, a plurality of lines arranged in non-decimal connective sections, the lines of each of said sec tions being divided decadally into groups each comprising a non-decimal number of lines and each of said groups being further divided into a plurality of subgroups each comprising a decade of lines, a plurality 01% link circuits, means associated with each 0 said link circuits comprising a plurality of group, subgroup, and units connecting relays for extending connections from said lines to said link circuits, an allotter for allotting one of said link circuits for use, a plurality of group, subgroup, and units controlling relays individual to each of said connective sections, and means operative upon the initiation of a call in a connective section to operate a group, a subgroup, and a units controlling relay corresponding to the location of said line in the section for controlling the corresponding connecting re lays of the allotted. link circuit.

'1'. In a telephone exchange system, a plurality of lines arranged in non-decimal connective sections, the linesof each of said sect-ions being divided decadully into groups each comprising a non-decimal number of i into a plurality ot subgroups, another link circuit, andmeans comprising a plurality of group, subgroup, and units relays for further extending connections from said first named link circuits to said latter link circuit.

8.-In a telephone exchange system. a plurality of link circuits arranged in nondeei-mal connective sections the link circuits of each of said sections being divided into a non-decin1al number-of groups each comprising a decimal number of lines and each of said groups being further divided into a plurality of subgroups, another link circuit, and means comprising a plurality of relays each individual to one of said groups of link circuits, a plurality of relays each individual to a particular subgroup in all of said groups, and a plurality of relays each individual to a particular link circuit of all of said subgroups for extending connections from said first named link circuits to said latter link circuit;

9. In a telephone exchange system a plurality of relays, multiple passive contacts therefor comprising conducting elements extending before all of said relays, and a plurality of active contacts associated with each of said relays for engaging all of said passive contacts.

10. In a telephone exchange system, a plurality of relays, multiple passive contacts therefor comprising bare conducting Wires 7 extendingbefore all of said relays, and a lit) plurality of active contacts associated with each of said relays for simultaneously en gaging With all of said passive contacts.

11. In a telephone exchange system, a group of incoming conductors, a plurality of groups of outgoing conductors, means for connecting said incoming conductors to any one of said groups of outgoing conductors comprising a plurality of relays, multiple passive contacts for said relays comprising a group of conducting elements extending before all of said relays, a plurality of active contacts associated With each of said relays for cooperation respectively with said conducting elements, and means for extending Said incoming conductors to said conducting elements.

12. 1n a telephone exchange system a group of incoming conductors, a plurality of groupso l' out-going conductors, means forconnecting said incoming conductors to any one of said groups of outgoing conductors ctnnprisinga plurality of relays, multiple passive contacts for said relays comprising a group ot' conducting elements extending before all of said relays and normally 81% trically isolated, a plurality of activeicon tacts associated with each of said "relays for cooperation respectively withsaid conducting elements, and means tor extending said; incoming conductors to said conducting sle ments.

13. In a telephone exchange system, a, group of incoming conductors, a plurality of groups of outgoing conductors, meansior; connecting said incomingconductors to any: one of said groups of outgoing conductorscomprising a pli'irality of groups; of relays, multiple passive contacts foreachgroup of relays comprising a roup of conducting; elements extending b ire allofthe'relayflof a group, a plurality of active contacts; associated with each of said relays for cooperation respectively with said cottdlftfiltingelements, and means for connectingsaid in coming conductors to the passive contacts of any one of said groups of relays.

l i. In a telephone exchange system, a plurality of lines arranged in connectivesections, the lines of each section being di vided into a plurality of-groups,a link circuit, and a plurality of groups of connective relays and passive conducting elements extending before all of the relays of said groups and cooperating With the active contacts thereoffor extending connections from said lines to said link circuits.

15. In a telephone exchange system, a plurality of lines arranged in connective sections, the lines of each section being divided into a plurality of groups-and each of said groups being further divided-into a plurality of subgroupaa link circuit, and means for extending connections trom said lines to said link circuit comprising a plurality of relays each individual to one of said groups of lines. a plurality of relays each individual to a particular subgroupof all of said groups, passive conductingele ment-s extending before all of said group and sub-group relays and cooperating with the active contacts thereof, and a plurality of relays each individual-to a particular line in all of said sub-groups.

16. In a telephone exchange system, a plurality of lines arranged in connective seetions, the lines of eachsection being divided lOIl into a plurality of groups and each of said groups being further divided into a plurality of sub-groups, a link circuit, and means for extending connections from said lines to said link circuit comprising a plurality of relays each individual to one of said groups of lines, a plurality of relays each individual to a particular subgroup of all of said groups, multiple passive contacts for said group and sub-group relays comprising bare conducting elements extending before all of said group and subgroup relays and cooperating with the active contacts thereof, and a plurality or relays each individual to a particular line in all of said sub-groups.

17. In a telephone exchange system, a plurality of lines arranged in connective sections, the lines of each section being divided into a plurality of groups and each of said groups being further divided into a plurality of sub-groups, a link circuit, and means for extending connections from said lines to said link circuit comprising a plurality of relays each individual to one of said groups of lines, a plurality of relays each individual to a particular sub-group of all of said groups, multiple passive contacts for said group and subroup relays comprising electrically isolated Wires extending before all of said group and sub-group relays and cooperating With the active contacts thereof, and a plurality of relays each individual to a particular line in all of said sub-groups.

18. In a telephone exchange system, a plu rality of lines arranged in connective sections, the lines of each of said sections being divided into a plurality otgroups and each of said groups being further divided into a plurality of sub-groups, a link circuit, means for extending connections from said lines to said link circuit comprising a plurality of relays each individual to one of said grou s of lines, a plurality of relays each in i vidual to a particular sub-group of all of said groups, multiple passive contacts for all of said group and sub-group relays comprising a plurality of sets of conducting elements equal in number to the number of lines in each group and divided into a number of sections corresponding to the number of sub-groups in each group of lines, and a plurality of relays each individual to a particular line in all of said sub-groups.

19. In a telephone system, groups of lines, a group of links, a magnet individual to each said group of lines for extending said lines of a group to said group of links, said group of links being divided into subgroups,

a group of secondary links. a magnet individual to each said subgroup of links for ex tending maid links of said subgroup to said group o secondary links, a tertiary link, and a magnet individual to each of said secondary links for extending each of said secondary links to said tertiary link.

20. In a telephone system, groups of lines, a group of links, a magnet individual to each said group of lines for extending said lines of a group to said group of links, said group of links being divided into subgroups, a group of secondary links, a magnet indi vidual to each said subgroup of links for extending said links of said subgroup to said group of secondary links, a tertiary link, a magnet individual to each of said secondary links for extending each of said secondary links to said tertiary link and means for simultaneously operating a magnet of each group to extend a line through a link to a secondary link and thence to said tertiary link.

:21. In a telephone system, groups of lines, a group of links. a magnet individual to each said group of lines for extending said lines of a group to said group of links, said group of links being divided into subgroups, a group of secondary links, a magnet indi- .vidual to each said subgroup of links for extending said links of said subgroup to said group of secondary links, a selector circuit and a magnet individual to each of said secondary links for extending each of said secondary links to said selector circuit.

The combination in a switching system ol incoming lines, link circuits and outgoing lines. with means for establishing line-linkline connections comprising fixed conducting elements constituting said link circuits, a set of incoming line contacts, a set of outgoing line contacts and means for simultaneously moving said sets of contacts to engage said fixed conducting elements.

The coiul'iination in a switching system of incoming lines, link circuits and outgoing lines, with means tor establishing linelinkline connections comprising an open grid of fixed conductors constituting said link circuits, a set of incoming line contacts, a set of outgoing line contacts and means for simultaneously moving said sets of contacts to engage said fixed conductors.

In witness whereof, I hereunto subscribe my name this 13th day of December A. 1)., 1920.

SAMUEL B. WILLIAMS, JR.