US2327466A - Automatic toll ticketing system - Google Patents

Description

Aug. 24-, 1943. L. J. SCOTT AUTOMATIC TOLL TICKETING SYSTEM Filed'June 27, 1942 3 Sheets-Sheet l lNl/ENTOP L. J SCOTT ATTORNEY Aug. 24, 1943.

L. J. SCOTT AUTOMATIC TOLL TICKETING SYSTEM Filed June 27, 1942 5 Sheets-Sheet 2 INVENTOR L. J SCOTT 6P6. M

AZiTO/PNLQV Patented Aug. 24, 1943 UNITED STATES PATENT OFFICE AUTOMCATIC TOLL TICKETING SYSTEM.

Lyle J. Scott, Chatham, N. J;, assignor to Bell. Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application June 27, 1942, Serial No. 4:48,?85

aonims, (o1. 179 1s This invention relates to a telephone'systein and more particularly to an out-trunksecondary switch circuit for distributing calls to a group of outgoing trunks. The invention is more spe cifically applicable to an automatic ticketing system of the type disclosed in the application of J. W. Gocderham, Serial No. M81782, filed concurrently herewith.

In the system disclosed therein provisions are made whereby subscribers may secure connections to the nearby toll area by dialing. Thisis accomplished by the provision of a group of automatic ticketing trunks each provided witl a ticket printer, to an idle one of which a calling subscriber may secure a connection by dialing one, two or three digits or letters of the office designation of a subscribers line which ,termi nates in an office of the nearby toll area and from which trunk a connection is extended by selector switch equipment. The selector switch equipment by which connections are extended from ticketing trunks" is controlled by senders, an idle one of which is associated with a trunk by a trunk finder individual to the sender when the trunk is taken for use. The sender is also equipped to control the ticket printer to print the oifice code and numerical digits of the calling line number, the ofiice code and numerical digits of the called line number and to print other information required on the toll ticket.' It is therefore essential to reconstruct the' ofiice code digits which a subscriber dials to extend a connection to a ticketing trunk and to identify the calling line. 'For thispurpose a plurality of identifiersis provided; an idle one of which is associated with a sender over an identifier-connector following the seizure of the sender and which identifier is then connected with the calling trunk over a trunk-identifier-connector circuitr groups of one hundred trunks each maybe provided, each main group being divided into five subgroups of twenty trunks each and each of saidsubgroups beingfurther divided into two or more have branches terminating in bank levels of first,

second and third selectors.

- 40 For giving automatic ticketing service two main In somecases where the tra'flic to a particular ofiice in the toll area is not great, a full selector bank level having access to ten trunks may not be necessary. It is then possible through the use of a divided level selector of the type .tr unk secondary switches, one group of such switches having access to a maximum of twenty of the automatic ticketing trunks and the other group of such switches having accessto a maximum of twenty other ticketing trunks.

Each ticketing trunk is provided with a sleeve relay connected to the sleeve conductor of each bank level appearanceo-f the trunk in first, sec- 0nd or third selector banks or in the bank of a divided level selector and these relays control the establishment of signaling circuits over code leads extending from the trunk to the identifier over contacts of the operated trunk-identifier connector, there being one such code lead for each oflice route which may be completed over the trunk. Those code leads are employed to assist the identifier in reconstructing the office code digits of a wanted line dialed by a subscriberto seize a ticketing trunk. If one such code lead were provided for all twenty of the ticketing trunks accessible to a rotary out-trunk switch for a particular route and all twenty of such trunks were connectable to an identifier over the same trunk-identifier-connector, it would be impossible to complete the connection to such route should the single trunk-identifier connector fail to operate. a 7

It is the object of the present invention to guard against this possible failure bydividing the twenty trunks accessible to an'out-trunk secondary switch into two or more smaller subgroups each subgroup of trunks being associable with an identifier over a different trunk-identitier-connector, by providing access to each subgroup of trunks over different portions of the banks of the out-trunk switch and'by providing an additional bank on the out-trunk switch over the separate portions o f which code leadsfeach relating to the same office route, may be extended to the identifier'over different trunk-identifier-connectors.

As illustrated, a subscriber desiring a connection to a line terminating in an office of a nearby toll area which may be reached over a ticketing trunk by setting a first selector, a divided level second selector and a rotary out-trunk switch by dialing the three code letters of the ofiice designation of the calling line, first removes his receiver from the switchhook whereupon an idle line finder, paired witha first selector, is started in search of the calling line. When the line has been found the usual dial tone is transmitted to the calling line and the subscriber hearing the tone then proceeds to dial the office code digits or letters and numerical digits of the wanted line number. In response to the dialing of the first code digit, a first selector is operated to select an idle trunk extending to an i; le selector" oi the divided level type which has access to ticketing trunk through a rotary out-trunk secondary switch and, in response to the dialing of the sec end or the second. and third code digits of the ofdesignation this selector is operated to sele'otan idle trunk terminatinginan out-trunk secondary switch.) The out-trunk secondary switch normally standsi'n engagement with the te'rrninals'of an idle ticketing trunk and therefore when the out-trunk switch is seized connelcti on is e'xtended'froin the calling line to the idle, ticketing trunk.

open the seizure of the ticketing trunk an idle sender is associated with the trunk and the sleeve relay of the trunk, which is allocate" to the outtrunk switch and to the banlzlevel appearance of the trunk incoming thereto. from the preceding selector, isope'rated preparatory to establishing a code signaling circuit to the identifier. The sender following its seizure establishes a connection with an idle identifier which, in turn, becomes as soc iat e d with theseized ticketing trunk over a trunk-identifier connector through the operation of a m'ulticontact relay or the conector which has access .to the subgroup of m les in which the calling trunk is located and by the ober ation of a eiii eeam relay in awn-mil The code signaling circuit prepared by thesleeve lelayof the trunk is then completed over two banks of the out-trunk secondary switcf and is sie dii ih id n f ve h sel information regarding theofiice code digits which the calling subscriber has dialed to reach-the trunk. If all threeoihcecode digits were dialed to reach the trunk all ofthe required information be given to identifier over the code leads but; ifbut two office code digits were d aled to reachthe trunk and the third code digit was register ed in the register associated with the trunk, theninformationconcerning the first two code digits is given to the identifier over the code lead and the setting of the trunk register which is transferred to the identifier over .circuitsestablished through.. the trunk-identifier-connector supplie s the identifier with information con erning the third code digit dialed. Tie combination of this information may then be employed to inform the sender as tothe complete: ofiice designation ofthe called line;

The invention having been described in a general mannenreference may be had to the follow ing detaileddescription thereof taken in conne tion with the accompanying drawings, in which: Fig.1 shows schematically calling linesyline finders, and trains of first, second and thir l'ectors for "extending connections from a calling line to automatic ticketing trunks two of which are illustrated, and a selector switch of the type having access over a divided bank level to two groups of outgoing trunks;

Fig. 2 shows a rotary outtrunk secondary switch in accordance with the present invention accessible from a trunk incoming from the divided bank level switch and having access to two subgroups of ticketing trunks; and

Fig. '3 shows trunk-identifier oi-mentors over which control conductors from two groups of automatic ticketing trunks may be extended to that one of a plurality of identifiers which has been seizedby a sender in response to the seizure of the trunk} To" completely" visualize the invention, Fig. 2 should be placed to the right of Fig. 1 and 3 should be placed to the right of Fig. 2.

The line finders H13, H36 and 125, the first selectors Hi6, ill! and H28, and the third selector Hi may be of the well-known step-by-step type seiied in response to the dialing or the first edde digit of ertain'distant braces, in fsfi-onse to the dialing of thefirs't and second code digits of other offices and in response to the dialEngv of the three code digits of still other oifices. To siniplify the disclosure, but two g'ro s or t ke'tiiig, trunks are shown for serving 60 offices of the toll. area. is the conmeidal use of the system, however, a plurality er roups of trunks would be required to handle the t Z t affididr xa'rnfil, two hundr cl trunks (Iii as into ten grouiis and each group divided into two or ifnoi'e subgroups. same of the subgroups would.

- be made accessible only from time. levels or first selectors, other subgroups would be made accesrein bank levels of second seiecto'rsand still other subgroups would befnadeaccessibie. only from bank levels of third selectors. The trunking 'seiieme' aay' therefore be made duite fleiiible for allocating the trunk groups in accogaaiice was thedensity er the trans- The selector switch Hz of Fig. i maybeof the a divided level stp-by-step type disclosed,- for example, in Patent No. 2,249,067, ranted/31119 16,,

1941 to W. Wadsworth and having access over the same bank level thereof to; two groups of trunks terminating-in rotary out-trunk secondary switches. one such trunk is schematics-111i secofjtm general type disclosed. in Patent a 1,472,425, granted October so, 1923 to Forster: et a1, butiis or the non-sentenc type. The. switch 21:0v is disclosed as having access to ranches of the two trunk greets ihcludi i ticketing thinks H3 and! 1.4 but itis to be understood that it could have access to more. than. two trunk grou 's. a

) Two of the ten tiiink-idiitifier-connector circults which are required to connect any one. at the twQhundred trunks to the identifier seized to serve conntition are disclosed in no. 3. Each connector circuit serves meaty tr its and is provided With a Inulticofitadt $61 each idfitifier and with a lock-out relay for each identifier.-

To more clearly set forth the novel features of the invention, it will be assumed that the callin subscriber whose substation is indicated by the numeral Itil initiates a call for a toll connection to a subscribers line. terminating in an office of the toll area to which the calling subscriber is permitted access by dialing. Upon the removal of the receiver from the switchhook an idle line finder, such as IE3, is started in search of the calling line in the well-known manner. When the line finder has found the calling line the usual dial tone is transmitted over the calling line to inform the subscriber that his line has been con-- nected with a first selector Iii-'5, paired with the line finder m3, and that he may therefore commence dialing the digits of the wanted line number. i

It will be assumed that the subscriber desires a connection with a line'whose directorynumber The brushes of switch WEB-therefore remain in engagement with the terminals of trunk H3 and a dialing loop is extended from the calling line over the connection established therefrom, over the brushes 213i and 2620f switch and through the winding of the line relayinot shown) of trunk H3. In response to the operation of such line relay a sender becomes associated with the trunk and ground is connected'to conductor 223 to mark the trunk as busy. With direct ground connected to conductor 223 relay 218 now operates, if it has not previously operated, and sleeve relay 2539 is held operated from such ground on conductor 223, over brush 203 and over the upper front contacts and through the lower winding of V relay 299 to battery. This busy ground is also is PLEA-1345 and that a ticketing trunk over which a connection to that line may be extended, may be reached fro-m the second level of the divided level selector H2 and through the rotary out-trunk secondary switch 269. The calling subscriber upon hearing the dial tone therefore proceeds to dial the office code letters K, R, A' and the numerical digits 1, 3, 4, 5. In response to the dialing of the first office code letter K, which has a numerica1 equivalent 5, the brushes of the first selector [66 are raised to a position opposite the fifth level ofits bank whereupon they rotate to select an idle selector I I2 of the divided level type. In response to the dialing of the second office code letter R, which has a numerical equivalent 7, the brushes of selector H2 are'raised to a position opposite the seventh level of its bank. It; will be assumed that the'swit'ch'is arranged to operate its shaft contacts when the brushes are raised to this level whereupon. the switch shaft is released into its normal position whereby'the second dialed code letter R is absorbed and a brush. selection is made as fully disclosed in the Wadsworth" patent hereinbefore referred to. In response to the dialing of the third ofilce cod letter A, which has the numerical equivalent 2, the brushes are again raised to a position opposite the second bank level and are then rotated to select an idle trunk ter' minating in the second group of such bank level. It will be assumed that the trunk I I5 is found to be idle and is therefore seized. Each of thetrunks of the group terminates in a rotary out-trunk secondary switch 265 of the type which normally stands upon the terminals of an idle outgoing or ticketing trunk. 7 It will be assumed that the switch 2% and other similar switches of the same group are at the time standing on terminals allocated to the ticketing trunk I I3.

When therefore the'trunk H5 is seized by the switch H2, a circuit is established from ground at switch H2 over sleeve conductor I29 of trunk I I5, over normal contacts of test jack 2 I I, through the upper low resistance winding of sleeve relay 269, over brush 283 to battery through the winding of relay 258 and in parallel therewith over the upper back contact of relay 2i8and through resistance 2I9 to battery. -A circuit in parallel with the winding of relay 218 and resistance 2H9 is also established over the upper back'contact of'relay 2%, over the interrupter contacts of stepping magnet 22S and back contacts of relay 221 to battery through the winding of steppingrelay 222. Relay 289 operates but the winding of relay 222 being shunted by the winding of relay 2l8 and resistance2l9, relay 222 does; not operate.

connected to sleeve conductor [253 to hold the previously operated. line finder m3 and selectors Hi6 and I i2 from releasing.

With direct ground connected to conductor 223, .a circuit is established over brush 2% of other switches of the same group as switch 238 whose brushes may be in engagement with the multiple terminals ofthe same trunk Hi5, thence over the upper back contact of the associated sleeve relay corresponding to relay 2%, over. the interrupter contacts of the stepping magnet 229 of such switch, contacts of relay iii and to battery through the winding of the stepping relay 222 of such switch. Relay thereupon operates in turn causing the operation of the associated stepping magnet 22% which upon operating opens the circuit of relay 222p Relay 222 then releases, in turn releasing magnet 220. Thus relay 222 and magnet 220 reciprocally control each other to cause magnet 22% to advance the switch brushes step by step until an idle outgoing trunk is encountered at which time the. brush 2% will find no busy ground and the switch brushesrwill be arrested in engagement with the terminals of such idle trunk, In this manner all out-trunk switches whose brushes are engaged with the multiple terminals of trunk H3 are advanced to preselect other idle ticketing trunks.

To guard against the unnecessary step-by-step advance of out-trunk secondary switches in search of an idle ticketing trunk should all ticketing trunks become busy and their associated relays 218 all be operated, relays 221 and 225 are provided. Relay 225 is maintained operated over the paralleled back contacts of relays idof all trunks to which the group of switches including switch 260 have access, but should all such trunks become busy relay 225 releases to close an alarm circuit and to cause the operation of relay 22L Relay 22! upon operating opens the circuits for the stepping relays 222 of all of the out-trunk switches of the group thereby preventing the stepping of such switches.

Following the eizure of an idle trunk the next digit dialed by the calling subscriber subsequent to the dialing of the code digit which resulted in the seizure of the trunk, in the case assumed, the thousands digit 1 is registered in the register associated with the trunk and thereafter the remaining numerical digits dialed by the subscriber are registered in registers of the sender which has become associated with the trunk. As soon as a digit has been registered in the sender, an idle identifier for identifying the calling line and for reconstructing the called office code designation is associated with the sender'over an identifier-connector as described in the application of J. W. Gooderham' hereinbefore referredto and the identifieris informed, throughthe prior o'per'ation of the trunk finder, in which main group of one hundred trunks and in which of two ten-trunk subgroups of such main group the calling trunk is located;

It will he assumed. that the first identifier has been taken for use and that therefore a circuit is established which may. be traced in part over conductor 35!, through the-winding oflockout relay BRIEF-allocated to-the first identifier and to the trunk identifier ccnnector circuit having ac'cessto the Nos. 0 and 9 tentrum; subgroups of the main group ef trunks in men the calling trunk is assumed to be located, "over the inner upper normal contacts of 'iia'r lock-out relays "allocated to other identifier 300E operates if the trunk-ldentifler connecter circuit is not at the time being used by another identifier on anothercall, locks over upper inner alternate contacts to ground; establish-es an operating circuit for the multicontact relay 3625 from ground through the \ifinding of such relay over the inner lower front Contact o f'iv 300E and through resistance 583 to battery, and establishes a circuit from battery through resistance 384, over its middleupper front contact I trol conductors are extended from the calling trunk to the identifier.

It is to he noted that to serve each maing-reup nect'or circuits, of which two are disclosed in Fig. 3, are provided, the connector circuit comprising the look-out relays EMF toZifiEL a the multicontact relays Still to 3321' serving the Nos. 0 and 9 ten-trunk subgroups or twenty trunks, the connector circuit com; isingthe lc'ok out relays 3561" to NEIL and the multicontact relays 352? to MEL serv'lng'the-Nos. 1- 2116.4 tentrunk subgroups or twenty trunks, and the three other connector circuits (not shown) serving-respectively subgroups 2 and 5, 3 and 21116.7 and 8. A similar group (if five connector would serve the second group of one hundred' truhl v In add tion to the Sleeve relay 2E3 the ti' unk M3 is provided with a sleeve relay,such-as relays Z06, 21 's, 198, etc. for each bank level appea -nce of the trunk each of these relays controls thecontinuity of a circuit over a separatecode lead. The code leads controlled. by these r lays; such as leads 2E2, 255, 216, etc. are-, together w'ith theccde lead. extending tro'mthe' bank-assm ciated with brush of the rotaiyiout trunk secondary switch 232, terminated on the ores-son'necting rack associated With-11116 trunkidcnl-ifier-connector circuit which has access to the subgroup of trunks in which 131 n cated. Similarly the code leads associated with other trunks of thesaine subgroup are also terminated on the rack Thus the code leads of twenty trunks terminate on-rack 353 3 the same the code leads frornthewenty trunks including trunk EM are connected to terminals onthe cross-connectingrack 31 3 associated With-the other trunk-identifier-ccnncctor disclosed in Fig.3.

The "code leads Whichterminate ln the rack to ground. Relay 7 circuits 3'05 may be cross-connectedthereover to terminal's' which are connected to the multiple con tracts of multicontact relays 3021 to 3021. and connected through the operation of one of such relays: to a plurality of code leads extending to the identifier. Similarly, the code leads which 'erminate'in the rack'3 I 6 may be cross-connected thereover to terminals which are connected" to the multi le c ontacts'o'f multicontact relays 3 I 2! to 3|2L and connected through the operation of such relays to a plurality of code leads extending to the identifier, The numberof code leads extending to the identifier will depend upon the number of possible route appearances of the trunks at the banks ofselectors. For example, if eight of the levels ofthe first selectors were involved in ticketing traflic there would be a maximum of eight code leads corresponding to the eight appearances through the first selectors.

a like manner the number or route appearances that might occur from the bank'levels of second selectonsavailable for ticketing traffic w'ouldlbe eight times eight or sixty-four apfil clearances or code leads if all two-digit codes were involved in outgoing. ticketing .trufilc. The number of route appearencesfrom the banks of third selectors and front the levels of divided level selectors is an indeterminate number depending upon the number of routes involved and therefore the number of code leads required for such three di'git codes also indeterminate. By means of the cross-connection racks .396 and H6, th'e' cod'e leads the sleeve relays of trunks, such :as" lead 2l 2.,rw-hioh are associated with the same route appearance, can be connected togather, the only code leads brought through the trunk-identifier 'conneotor circuit being those required dist troute appearances. In the identifier, the ode-leads may be cross-connected to control the itcttei s dialed hy a calling subscriber as fully disclosedin the application of M. B. McDaw-itt, Serial No; 4 5837189, filed concurrently herewith.

Referrnrgagai-n to the sout-trunk-seoondary 'swilnih ZDLLit .is to be .notedth'ttt the terminals of iits banks are divided into two groups, the terminals of the first grout) being-connected to the ten trunks of i one subg' roup of trunln; includ .ing trunk ma, :whicmt win gee-assumed may' be associated with fan identifier over the trunk identifier-connector circuit disclosed in the upper portion of Fig. 3 andwith which the crossconnection rack Hem-associated. Consequently, 'thertnunk itermlnals-i-appearing in the first half of the-ibank fof Switch 200 with which brush 1U! isiaasseoia'ted Jam multipled' together and connect tocodeiie'ad 2:24 Wliich'termlnates on the crossconnecting rackSilS'. .Theiterminals-of the other group of the banks of switch ZGU-areconriected to-the' tenitrunlzs :o'f asecondsubgroup of trunks including itrunk' 113M, which it will be assumed may he associated with an identifier over the ti unkeidentiiier-connector circuit disposedin the lower portion :ofliig. 3 andzwithwhi'ch the cross .connectiomrdck- 13% associated. Consequently, the 'trunk terminals appearing in the second half cftheflbanlc :of switch .ZOD With Which brush 205 is :assnciated are strapped 1.together "and conne ted. to nude lead 25%. :Thus, if any one of the first ten'ttrunksjis selected by switch 200'; code lead Z24 Whlchis common .to all l of such trunks and :appertains ito'ithe s'ame appearance in the bank level-zofswitch 3H2 will oe employed' and if any "one o'f the second I ten trunks is selected by switch: illl codei-leadz dlwhich is common to' an reconstruction of the ofiice codeof such trunks and appertains to the same appearance in the same bank level of switch H2 will be employed.

Following the operation of multicontact relay 3%2F and trunk relay 2I3 as previously described, battery connected to conductor 36'! at the identifier is connected over contacts 308 of relay 382E, conductor 2M, contacts of relay 2l3, the terminal engaged by brush 294 of switch 2&8, the lower contacts of operated sleeve relay 209, the

contact of the bank engaged by brush 205, code lead 224, across strapped terminals of cross-connecting rack 365, contacts 3|! of relay 302F and over code lead 3I8 to the identifier. Had another trunk of the same subgroup as trunk H3 been seized, then upon the operation of relay 30276 and the connector relay of such trunk corresponding to relay H3, a circuit would have been established as just traced over contacts 308 of relay 3132B, contacts of relay 2|3 of such trunk, the individual terminal of such trunk engaged by brush 234, over the lower contacts of relay 299, brush 235 and the terminal of such trunk engaged by brush 2535, code lead 224 and thence as traced to code lead SIB. Similarly, had trunk N4 of the other subgroup of ten trunks been seized, then multicontact relay 3l2F and connector relay 253 of the trunk would have been operated and thereafter upon the connection of battery to conductor 35'! such battery would have been extended over contacts 32| of relay 3I2F, conductor 254, contacts of relay 253, the individual terminal of such trunk engaged by brush 264, over the lower contacts of relay 209, brush 205 and the individual terminal of the trunk engaged thereby, over code lead 264 and strapped terminals of cross-connecting rack 3V5, contacts 322 of relay 3l2F to code lead 3|8. By dividing a group of trunks between two trunk-identifierconnector circuits and enabling the out-trunk secondary switch to extend the code lead over either connector circuit depending upon the location of a trunk in the group with respect to the connector circuit, it is possible to obviate tying up an entire group of twenty trunks should'a trouble condition occur in one of the trunk-identifier-connectors serving such group.

While a twenty-trunk group has been shown as served by two trunk-identifier-connector circuits and the code lead bank of the rotary outtrunk secondary switch 200 with which brush 205 cooperates, has therefore been divided into two corresponding strapped sections, it is to be understood that the twenty-trunk group could be divided to be served by a larger number of the trunk-identifier-connector circuits and the bank of switch 2m: with which brush 205 cooperates could be divided into a similar number of strapped terminal sections connectable by separate code leads to the several trunk-identifierconnector circuits.

What is claimed is:

1. In a telephone system, an incoming trunk, a plurality of outgoing trunks divided into subgroups, a switch operable upon the seizure of said incoming trunk to extend said incoming trunk to an idle one of said outgoing trunks, apparatus common to said outgoing trunks, a control circuit, a plurality of means equal in number to said subgroups of outgoing trunks for extending said control circuit from any one of said trunks to said apparatus, means in said switch for extending said control circuit to that one of said control circuit extending means allocated to the subgroup of trunks in which said selected trunk is located, and a relay operable upon the seizure of an idle outgoing trunk for completing said control circuit.

2. In a telephone system, an incoming trunk, a plurality of outgoing trunks divided into sub groups, a switch operable upon the seizure of said incoming trunk to extend said incoming trunk to an idle one of said outgoing trunks, apparatus common to said outgoing trunks, a control circuit, means equal in number to said subgroups of trunks for extending said circuit from any one of said trunks to said apparatus, said control circuit being individualized to each outgoing trunk over one bank of said switch and individualized to the control circuit extending means over another bank of said switch and a relay operable upon the seizure of an idle outgoing trunk for joining the two sections of said control circuit over the switch brushes cooperating with said banks.

3. In a telephone system, an incoming trunk, a plurality of outgoing trunks divided into a plurality of subgroups, a selector switch operable upon the seizure of said incoming trunk to extend said incoming trunk to an idle one of said outgoing trunks, apparatus common to said out going trunks, a control circuit, a plurality of means equal in number to said subgroups of outgoing trunks for extending said control circuit from any one of said outgoing trunks to said apparatus, branches of said control circuit individual respectively to said outgoing trunks and terminating in individual terminals of one bank of said switch, other branches of said control circuit individual respectively to said control circuit extending means and terminating in terminals of another bank of said switch which are multipled together in accordance with the subgrouping of said outgoing trunks and a relay operable upon the seizure of an idle outgoing trunk for uniting a first branch with a second branch over said banks and their associated brushes.

LYLE J. SCOTT;

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