US1541347A - Telephone-exchange system - Google Patents

Description

June 9; 1925.

C. L. GOODRUM TELEPHONE EXCHANGE SYSTEM 2 Sheets-Sheet l /nven for.'

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C. L. GOODRUM TELEPHONE EXCHANGE SYSTEM Filed July 1, 1920 2 Sheets-Sheet 2 Nw O OO OOOOOO @www NN No .ww N omooo Il. m40 RQW@ o o IL Q L OO O o E o@ .U y w QQ ww r `Q Z A C w Q?- /n Verl fof. Char/e5 L. Good/'um Patented .lune 9, 1925.

narran STATES 1541,34? PATENT: oFFlcE.

CHAR-LES L. GOODRUM, OF NEVI YORK, N. Y., ASSIGNOR TO WESTERN ELECTRIC COM.- PANY, INCORPGRATED, OF NEW YORK, N. Y., CORIEORATION OF'NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Application filed .Tuly 1, 1920. Serial No. 393,389.

.7710 all whom. t may concern.

Be it known that l, CHARLEs L. CrooDnUM, a citizen of the United States, residing at New York, in the county of New York, State of New York, have invented certain new and useful Improvements in Telephone-Exchange'SysteIns, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone exchange systems and particularly to circuit arrangements for private branch exchanges employing automatic switching apparatus, where such exchanges are used in connection with central oiiices.

The object of the invention is to provide means whereby a minimum number of switching means will be employed at the private branch exchange for interconnecting subscribers thereat and for establishing connections over trunk circuits to the central oiiice.

In accordance with the object of the in-` vention each subscribers line of the private branch exchange is provided with a nonnumeroial switch. Accessible to these switches are a number of connector switches for the purpose of connecting a calling to a called line. Cn calls to the cen tral otlice, however, a line is lirst extended to a connector switch and upon reaching a pre-determined Contact thereat, a switchingoperation at the non-numercial switch is caused automatically to take place so that.

the connection with an idle trunk is es tablished independently of the connector. The connector is thereupon released and is available for establishing local connections. F or a more complete understanding ot the invention, reference may be had to the following description in connection with the accompanying drawings in which Fig. l. shows an embodiment of this invention einploying a line finder as a non-numercial switch and in which Fig. 2 shows an einbodiinent of the invention employing` a line switch as the non-numercial switch.

Referring to Fig. 1 of the drawings, there is shown a calling subscribers station *il 'and a called subscribers station B. Upon the initiation ot' a call by a subscriber at sub-station A, a line finder F is set in operation to extend the calling line over a link to a connector K. Under the control of an impulse sender 5 the subscriber of sub-station A may set the connector K upon the terminals of any desired line of Ythe private branch exchange. It, however, the subscriber of sub-station A desires to extend his line to the .central oilice, he will dial a pre-determined number, whereupon his line will be disconnected from the line tinder F and connected lto an idle finder switchv M for the purpose of extending his line to the central oliice. Connector switch yl andline finder switch F and the inter connecting link will thereupon be vreleased and are availablefor further use.

Referring to Fi 2 of the drawings, a calling subscriber and a called subscriber L are shown. In response to the initiation ot Va call, a line switch N extends the line of they calling subscriber over a link to an idle connector such as C. The subscriber of station G, may set the connector C upon the terminals of a desired line such as'L by manipulating his impulse sender S1. If, however, theV subscriber of station Cr desires a direct connection with the central office, he Vwill dial a pre-determined number,

whereupon line switch N will be caused to seek an idle trunk, such Vas T, leading to 'the central ollice. Connector C is thereupon released and is available i'or further use.

The apparatus and wiring necessary for testing and ringing a subscribers line have not been shown, since such operations are well known to those skilled in the art and are made in a manner similar to that disclosed in Pat. No. 1,231,018 of June 26, 1917, to C. L. Goodrum. Y lt is believed that the operation of this system will best be understood by tracing a call through the various switches. Upon the Vremoval oit the receiver from the switch hook at substation A, line relay 110 is energized over a path extending :trom grounded battery, lett hand winding of relay 110, the outer armature and back oontact ot relay 111, through the substation loop, the back contact and inner armature of relay 111 and right hand winding ot relay 110 to ground. Relay 110 in operating v completes a circuit for relay 112 over a cir cuit extending from ground, the armature and front contact ot relay 110, the inner right hand armature and back contact of slow to release relay 113', and winding of relay 112 to grounded battery. Upon the energization `of relay 112, a circuit for escape magnet 114 is completed over a path extending'from ground, iront contact and outer armature of relay 112, contacts 120 which are opened upon the iirst movement of the'brusllesand Winding of magnet 114 to grounded battery li/Iag'inet 114 in operating locks up over a path from grounded battery, the Winding' of magnet 114, right hand armature and front .Contact thereof, side switch arm 118 and brush 119,

vcontact 121, to ground at the inner armature and back contact olf agroup relay such 112 ifthe group relay is not energized, and 'provided that upon the initiation oi: ,this call brush 119 is not resting upon contact 121` Magnet 114 in operating also comg'iletcs a circuit for primary Stepping magnet 115, said circuit ,extending from grounded battery, the ironticontact and left hand armature .of magnet 114, armature and back fontact of stepping ma 'a .et 115' and side switch arm 117 to ground. Since the primary stepping` magnet 115 interrupts its own circuit, itcontinues to ,step as as magnet 114 remains energized. Magnet 114 remainsenergized long as brush. 119 which is of t-heloridging type engages Vidle terminals or terminals upon which ground is present. lWhen the brush 119 engages `contact A121 no ground will be present thereon due to relay 112 being energized, whereupon magnet 114 rele-ases .its armatures thereby opening lthe operating circuit tor stepping magnet 115, which ceases stepping. net 114 in retracting its armatures mores side switch arms 117v and 118 into their second positions, 1n position 2 ot the side switch arms the secondary stepping magnet 116 is energized and in attracting its armatures moves the brushes one step into eugagement with the first set of terminals. Upon the :first .step ot the brushes .escape magnet 114 is en Vized over a path extending troni grounded battery, the Winding oi'i magnet 114, outer i'ght band varmature and .liront contact o' stepp' magnet 116, the side switch arm 118 and -ts second contact, brush `144, to ground at the back contact and -armature olfline relays such as 110 to ground, it' the first terminal en"aged is not `that ofi the calling line. lr1`he bri hes ot the yrinder switch being oi the bridging type, magnet 114 loclred up through its right hand contacts, arm 118, brush 144 and its associated terminal to ground at the l ontacts ot the line relays and this circuit is not opened until the brushes of rthe linderswitch cen-ter upon the line terminals of the calling line. rrlhe stepping circuit tor secondary magnet 116 thus maint-ainecL until brushes 1401!.) 144 inclusive ot the line inder switch engage terminals 146 to 150 ir'iclusimeV respectively o the calling line. As soon this set ot terminals is'reached the locking cir for esape magnet 114 will be opened due .to Iline relay 110 being energiaed. Es# cape magnet 114 thereupon releases itsy armatures thereby moving side switch arms 11T, 122 and 118 into their third position, thus opening the stepping circuit for secondary magnet 11G. ln position f2 or" .the side switch arm 1117, a circuit is completed for cutoff relay '111 over a path extending from grounded battery, the Winding of cutoff relay 111, terminal 148, brush 142, and side switch arm 117 in its third position to ground ltelay 111 in opera-ting extends the calling line through to-line relay 182 fot'k the 'onnw or l and disconnects the line relay 11() from the calling line. rglhe latter in deenewrizing releases relay liinerelay oiY the connector K is .thus energized over path extending from groundedbattory, the lejt't hand winding oit relay 182, brush 140, terminal 45, through .the substation loop, thebaolr ,Contact and outer lett hand armature ot relay 118, terminal. 147 brush141 and right hand Winding o' relay 182 to ground. Relay 182 in opera ing completes a circuit at left hand armature and lront Contact for slow-to-release,relay 183.

The subscriber may non' proceed to send out impulses in accordance with the number ot' the desired substation. rllhe interruptions or the line circuitk caused by the Lsubscriber operating the sender S causes impulses to be sent to the stepping magnet 18,6 of the connector, which positions the proper brush below the group or" contracts containing .the df d line. The circuit for operating stepping magnet 186 may b e Atraced from grounde the armature and back contact of relay 1.82, the armature and front contract of slow to release relay 188, side switch 188 and. is.' contact and the Winding of stepping ur net 186 'to grounded battery. Upon .the .ist de-energization of line relay 182 in reponse to the sending of impulses a circuit completed for slou'to-release relay elay 184 in operating `at its outer armature and front contact comple-tes a circuit for escape magnet 101. Vllhen the line cirfuit becomes closed upon the termination of the .first set of impulses the sloW-to-release relay 184 dey-energizes due to the opening orn its circuit at the armature and bacl contact of relay 182. Relay 184 in retracting its armatures opens the circuit 'for escape ,magnet 101 which upon Cle-energizing moves theside suf'itch arms of connector K into position 2. The arm 188` thereupon substitutesthe secondary stepping magnet 187 in place ot the paint-ry stepping magnet 186 in the steppingcircuit. The interruptions co 1,responding to the -units digit are vthen sent to operate vthe magnet 187. in the following cirn cuit, grounded battery, Winding of secondary magnet 187 side switch arm 188 `and its second Contact, front contactaand armature ot' sloW-to-release relay 188, yandYarmature and back contact of relay'182 to ground.` The slow-to-release relay 183remains energized during the short interruptions of .the line relay corresponding to the units digit as in the operation of sending the tens digit. As before, the slow-to-release relay 184 is again energizedupon the rst deenergization of line relay 182 and energizes the escape magnet 101. Upon the cessation of the interruptions of the line circuit corresponding to the units digit, the slow to release relay 184 becomes deenergized thereby opening the circuit for escape magnet 101 which in deenergizing moves the side switch arms into position 3. The brushes 194, 195 and 196 of the connector switch K are now set upon the terminals 197, 198, and 199'respectively of the desired line. A description of the operation and a showing'of the apparatus necessary for testing and ringing the called subscriber is not deemed necessary since arrangement shown is applicable to any well known system. Upon the response of the called subscriber the side switch arms 191, 192, 193 and 188 of the connector K are moved into their fourth positions in the well known manner.

The calling subscriber is now supplied .with talking battery through the windings of line relay 182 and the called subscriber through the windings of relay 185. Upon the termination of the conversation and the restoration of the receiver to the switch hook at substation A, line relay 182 deenergizes thereby opening the circuit for slow-to-release relay 183 which complete circuit 'for release magnet 189 over a path extending from ground, armature and back Contact of relay 182, armature and back contact of relay 183, off normal contact 103 (closed upon the primary movement of the switch brushes), and winding of release magnet 189 to grounded battery. Release magnet 189 attracts vits armatures and locks up through its own contacts thereby restoring connector K to normal in the well known manner. Upon reaching normal position the off normal contacts 103 are'again opened and release magnet 189 deenergizes. At the moment the circuit is completed for release magnet 189 of the connector, a circuit was also completed for release magnet 190 of the linder switch, said circuit extending from ground, the armature and back contact of line relay 182, the armature and back contact of slow to release relay 183, side switch arm 122 and its third contact off normal contact 102 and winding of release magnet 190 to grounded battery. Release magnet 190 also locks up through its own contacts and causes the restoration of theline inder switch F to normal position. Upon reaching normal position the off normal contacts 102 are opened and release magnet 190 deenergizes.

through to the connector K in the same manner as heretofore described for an interconnection with subscriber B'. The subscriber will then operate his impulse sender S in accordance with a pre-determined number which, for the purpose of this disclosc ure will be assumed to be No. 94. Inresponse to the sending of the impulses corresponding to these digits theconnector K willrfirst be removed in a primary direction and then in a secondary direction as heretofore described for an interconnection, and the brushes 194, 195 and 196 will be positioned upon terminals 157, 158 and 159 respectively of connector K.

After having sent the second series of impulses, the escape magnet 101 will deenergiz'e, due to slow-to-release relay 184 releasing its armatures, tl'iereby moving sideI switch arms 191, 192, 193 and 188 into their third positions. Inf the third position of arm 193, a circuit is completed for relay 113 over a path extending fromground, the side switch arm 193 and its third contact, brush 196, terminal 159, brush 143 and terminal 149 of line finder F and right hand winding or' slo-w-to-release relay 113. Re-

lay 113 energizes and at theouter left hand armature and back contact thereof, the circuit for line relay 182 of the connector K is opened. lRelay 182 thereupon deenergizes causing in turn the deeuergization of slow-to-release relay 183. Release magnet. r190 of the line inderF and release magnet 189 of the connector K are thereupon `energized over paths previously traced causing the return of their respective switches to normal position. 7When switch F returns to normal the circuit for cutoi'lx relay 111 is-opened at the arm 117'. Relay 111 thereupon deenergizes thereby again connecting line'relay `110 to the lcalling` line. Line relay gs again energiz'edand slow-to-release Arelay 113 is maintained energized over winding of relay v110,'inner armature. andV back Contact of relay y111-through they substation loop, `the back contact and outer armature of relay 111 andfthence in parallel, one Vpath extending through the left hand winding-'of line relay 110 to battery, and the other path through the inner left hand armature and front contact and left hand ,winding of slow-to-release-relay 113 -a circuit extendingfrom ground, right hand to grounded battery, Relay 152 is then energized over a path extending from grounded battery, the winding of relay V152, through-the front contact and inner right hand armature ot relay 113 and the-front contact and armature of relay 110 to ground. Relay 152 in energizing completes a circuit for magnet 174 of tinder switch M oven a path extending from ground, liront contact and outer armature ot relay 15,2, contacts ofi'. normal 107, and the Winding of magnet 174 to grounded battery. l/Vagnvet 174 in energizing locksV up over a path similar to that described for magnet 114 ot the line finder F. A circuit is also completed for stepping magnet 175 over a path extending from ground, arm 1 77 ufinding, hack contact and armature of magnet v175 and lett armature and front Contact o1' magnet 17.4 to er. 1651 batter Stepping riagaet 17.5 new Continues .t0 Ster the' brushes 16:01to 163 inclusive ot line vfinder switcljilfffl or r its associated contacts. Whe-n the brush 145 engages Contact 151 no ground will he present thereon and magnet'174 Will loe deenergized thereby opening step Vping circuit for stepping magnet 1.75. MagnetV 174 in deenergizing inoyes the side switch arms 177, 123 and 109 into their secondi position. In position 2 of side switch brushes a circuit is completed Ylor secondary ,magnet 176. Magnet 176 in .attracting its armatures moves'the brushes `160 to 163 inclusive one step and closes a ,circuit for magnet 174' overa path eX- tending lfrom grounded battery, Winding magnet 174, outer armature and loa/cl; ,contact of magnet 176, arm. 109 and its second Contact, brush 163, to ground at the puter right hand armature of other relays such as 113'associated with the line vfinder switch M. Upon energization, magnet 174 locks up through its rightV hand Vcontacts over this circuit. Under control o1: stepping magnet 17 6, the brushes of the switch M are moved from terminal to terminal until terminal 167 is reached. Since relay 113 is energized the Vholding cincuit for magnet 174 at the outer right hand armature and back Contact of relay 113 is opened which will cause stepping magnet 174 to deenergize. Magnet 174 in deenergizing moves side switch arms 177, 123 and-10.9 from their second to'their third positions Due to the openingA of the .circuitforstepping'magnet 176 at the second contact oit side sxvitch arm 177, said steppingmagnet ceases lstepping. .A circuit is then completed orcutoltirelay 111 over a path extending from ground,'ar1n 17 7 and Iits third Contact, brush 162, terminal 166, and Winding-"ot cutoil relay 111`to `grounded battery. Relay 111 in attracting its armatures disconnects line relay 110 from the calling line and opens the locking circuit for relay 113. Relay 11'3'in'deenergizing extends the calli'ng'line through to`- terminals 164 and: 165 of' the line finder switch M. A `circuit is then completed for4 line relay 180 at the central ottico over a path extending 'from ground, the hack Contact and outer armature of relay 179, conductor 136', `lorush 160,

terminal 164, through the substation loop, haci:y contact and zo"ut er"le.tv .hand armature otrelay 113, terminal 165, brush 161, con- 'ductor 137, 'Tvinding of 1^elay"'-126, inner armature and o ck contact of relay 179 and Winding or' relay in attracting its arnatures completes a circuit for line siffnal 131' thushinldifcating to. 'the operator atv-the central oliice that a call has arrive-d. Relay 126 is also'elnergized thereby closingh circuit through its larma ture and front Contact' ot 'sloyuf to, release rela-y 127. Y i

Theopcrator at the central ofiice noting the lure-'signal may 'insert the answering plug` 106 ci 4any uell known cord circuit such l), t viortion Vonly et which `'is l own)v into j 1'73 and after having` in- Y -hscrib'er vd suhnner. i Upon 'compleiorf and restoration of the 4. 1 the'direct -e substation A, whereupon relay y'll d .-cnergize causing in turn the relay u127. fr circuit is then comrelease magnet 125 ot the line ver a path; extending from ground, fand oar-lr contact ot relay 126, arm ture and hack contact oit reay127, side switch arm'123 and its third Contact, Vott normal contacts 4133 and Winding,` ot magnet 125 to grounded battery Release magnet 125 energizes and locks lup' through its own contacts and tlirlough the ott normal contacts 133 and restores theline Lnder switch M to nornial position. Upon reaching` normal position contacts 133 are Vopened Whereupr'ni release i agnet 125 releases its armati Line rind-.er switch M in r'eturning` to normal opens the holdingcircuit for cutoff relay 111 vglhereijrpon this relay de--energizes and the Upon the removal of the receiver from the switch hoek` at sul'istation G, circuit for line relay 1.0 is :completed over a path cxtending' 'troni grounded lmttery, the winding ot relay 10, hack contact and outer lett hand arniature ot relay 11,. through the substation loop, inner lett hand armature and hack contact of re-ay 1.1 to ground. .f the brushes 24 to 28 inclusive of the switch VN are resting` upon the terminals to which a busy connector is connected or upon terminals With which direct trunks to the central slice are associated, ground will he connected to brush 26 and a circuit for motor magnet'12 Will he completed over a path extending from grounded battery.rv the Winding, armature and back contact of magnet 12, front contact E130 to ground. Relay'lSO and inner right hand armature of line relay 10 back Contact and right handy armature of relay 11, lefthand armature and back contact of slow to release relay 13 and brush 26 to ground. Cutoff relay 11 is short circuited and will therefore not energize. Motor magnet 12 in attracting its armature moves the brushes 211 to 23 inclusive of line switch M into engagen'ient with the next set of terminals of the line switch. Assuming` that upon the initiation of the call" the brushes were resting upon the first set of terminals shown for switch N and that the next set of terminals are busy, ground will be present on contact 9 thereby again completing the circuit for magnet 12 over a path extending from grounded battery, the winding, armature and back contact of magnet 12, the front contact and inner right hand armature of line relay 10, back Contact and right hand armature of cutoff relay 11, left hand armature and back contact of relay 13, brush 26 and terminal 9 to ground. Motor magnet 12 will again tlc-energize and step the brushes of the switch M into engagen'ient with the next set of terminals. Assuming that the next set of terminals to which the connector C is connected are idle, no ground will be present upony the test terminal 22 andmotor magnet 12 will therefor not be energized. A circuit will, however, be completed for cutoff relay 11 over a path extending from ground, the front contact and left hand armature of relay 10,l the winding of cutotf relay 1-, baci/r contact armature and winding of motor magnet 12 to grounded battery. Motor magnet 12 is marginal and will not operate in series with relay 11. Cutoff relay 11 in energizing disconnects line relay 10 from the calling line and extends the calling line through to the connector C. Line' relay 30 of the connector isthen energized over a path extending from ground, the left hand winding of relay30, terminal 20, brush 24, front Contact and outer left hand armature of relay 11, through the substation loop, 'the inner left hand armature and front contact of relay 11,` brush 25, terminal 21 and right hand winding'of relay 30 to grounded battery." Relay 30 in operating, at its right hand armaturey and front 'contact completea circuit for slow to release relay 31 'and relay 31 yin operating places ground upon terminal 22 to render the connector C busy and to hold relay 11 energized when line relay 10 releases. Belay'31 in attracting its right hand armature prepares a circuit forI slow release relay 34, which in turn when energized completesv a circuit at its outer armature andfront Contact for e'scape magnet 30.

The subscriber'rmay nowl proceed to send out impulses in accordance' with the number ofthe Ldesired line whereupon the' brushes staal' and e2 will be set upon the terminals ills 44;, and l5 of the called line in a manner similar to that heretofore described.

As heretofore stated, the testing and ringing operations are well known and it is not deemed necessary to complicate the drawing and the descriptive matter by describing sach operations.

Assuming that the subscriber at substation Cr desires a direct connection with the central oilice, he will after removing` the receiver from the switch hook dial the predetermined number which for the purpose of this description will be assumed to be 94. in response to the removal of the receiver from its switch hook line switch lvl will be caused to seek an idle connector as heretofore described, and in response to the sending of the impulses the brushes 40, 41 and 42 will be moved into engagement with terminals 90, 91 and 92 of the terminal bank of connector switch C. After the sending of the second set of impulses side switch arm 50 will be moved into its third position due to magnet SO releasing, whereupon a circuit for relay 13 will. be completed over a path extending from ground, arm 50 in its third position, brush e2, terminal 92, conductor 95, terminal 23, brush 27, the left hand winding of slow to release relay 13 and outer hand armature and back contact of relay 10 to grounded battery. Relay 13 attracts its armatures and locks up over a path extending' from grounded battery, `the right hand winding of relay 13, right hand armature and front contact thereof, brush 23, and terminal to ground. Relay 13 in energizing opens th'e holding circuit for cutolf relay 11 at the left hand armature and back contact of relay 13. Cutoff relay l1 thereupon de-energizes whereupon the circuit for line relay 10 is again completed. Relay 10 in attracting its armature again completes a circuit for motor magnet 12 over aA path extending from grounded battery, the winding, armature and l ack contact of-motor magnet 12, front contact and inner right hand armature of relay 10,v back contact and right hand armature of cutoff relay 11, left hand armature and front contact of relay 13, brush 28 and terminal 70 to ground. Under the'control of stepping magnet 12, the brushes 24 to 28 inclusive of line switch 10 are moved step by step over the terminals of such switch until the first idle trunk leading to the central oiiice is found. Assuming that terminal 29 is the first idle trunk leadking to the central oice, no ground will be VMotor magnet 12 will present thereon.

Cutoff relay 11 therefore cease stepping.

will then be energized overa path extendy ing from grounded battery, the winding, armature and back Contact of motor magnet 12, the winding' of'cu'toff'relay v11, vleft hand armature and front Contact of line relay 10 tog'roun'd. Cutoff relay 11 in attracting its armatures disconnects line relay lO from the calling line and extends the calling line through to the trunk conductors l and 2 leading`r to the central oltice, Relays and (lL/l of the trunk circuit are thereupon energized over a path extending from groui'id, the back ContactA and outer armature of relay 65, conductor il terminalO, brush 'rE/l1 Contact and outer left. hand armature ol' cutoll relay ll, through the substation loop, the inner left hand: armature and iront Contact oil relay il, brush terminal Gl, winding of relay 62, conductor f, inner armature and back Contact ot'ieiay G5, and winding of relay (il to grounded battery. Relay G52 in ene 'zing completes a; cir 't for slow to relcae relay @it Slow to rclease relay GP5V in energizing placesrgronnd upon terminal Q9 iter maintaining relay 13 in a locked conditiond Linear-clay Gl', at the central oliceiin energizing, completes acir cuit for line signal 67 thus indicating to the operator thereat. that a call has arrived.

The operator noting the line signal GT vwill insert the answering end of cord vircuit (a portion only ot which is l"o\vn) into jack 6G, whereupon relay (55 wh be energized thus disconnecting relay Gel trom the trunk conductors l and 2. Relay (Se in deenergizingiopens the circuit for line siin'ial 67. Battery gtorho'ldingj relay 62 ener iced and tor' talking is now supplied throi" jh the windings of repeatingl coil After having; inquired the wants of the calling subscriber Vthe operator may complete theI connection in the welLlrnO-:n manners Upon completion ot the conversation and the restoration of the receiver to the switch hoolat-substation G, relay GS will be de energized due to the opening of the direct current path over the trunk conductors l and 2. Relay 62 in releasing opens a ci'rcuit for relay 63v whichY in releasing removes ground rom'terminal 29 of the line switch. Upon the removal otthis ground relay 13 cle-energizes, which in turn releases cutoff relay 1l. Thesystem is thenready for the next call. Y c

While the invention has been shown in connectionwith trunks extending to a man'- ual exchange, it will be understood that: it is equally wells adaptable for use' in a system in which the trunks extend to an automatic exchange.

What is claimed is: y i

In a telephone systenntelephone lines, trunk lines, a link ci'rt'mit,VVV subscriber controlled means for including saidlink circuit in' connection between said 1 telephone lines and'pme'ans positively controlledby the sub"- scrlbfer for excluding saidfl-inl; circuit from a connection between a telephone-.line and a trunlrlinef Y v 2.' a telephone system, telephone lines, trunk lines, a series of automatic switches Yphone line and a trunk line.

including a non-numerical switch, subscriber controlled means for including said automatic switches in a connection between a calling and a called line, and means positivelj)r controlled by the subscriber tor ex- 'Y cluding all switches except said nonnumeri-V cal switch troma connection between a tele- 3. ln telephone system, a. calling anda called line, a trunk line, a non-numerical switch and a numerical switch, subscriber controlled means for operating` said switches to interconnect said calling and called lines, and means responsive to a predetern'iined setting ol said numerical switch torreleasing said numericalswitch and for establishing a connection betweenv said callingY line and said trunlr line through said non-numerical switch independently of said 'numerical switch.

l. ln a telephone system, a callingI line, a called line, a trunk line, a non-numerical and a numerical switch, an iin-pulse senderv for said calling line, means responsivev to the initiation ot'a call Vand thc actuation ot said sender for interconnecting saidwcalling'and called lines over a circuitincluding said nonnumerical switchV and saidf numerical switch, and means responsive to the initiation et a call anda predetermined actuation of said sender for releasing said numerical switch and tor interconnectingsaid calling lineand said trunk line over a circuit including said non-uumerical switch only.

5. In a telephone system, subscribers lines, iirst and second switching means, an impulse sender for opera-ting saidt second switching` means to interconnect iafcalling and-a called line, trunk lines, andy means actuated upon the sending of a predetermined numberV ot impulses forreleasing said second switching means and for causing said first switchin means to interconnect said callingV line and an idle trunk line'.

6. In a' telephone system, subscribers lines, first and second switching means. an impulse sender fon operating said switching means to'interconnect a" calling and a calledV line, trunk lines; and means actuated upon the sendingot a predetermined number of 'mr pulses for causing said'firstsw-itching' means to become disconnected fromI said second switching means and to interconnect said calling lineY and an'idle trunk linethrough said rst switching means to the exclusion of said second switchingmeans.

7. In a telephone system, subscribers lines, an automatically operating switching mechanism,n a directively controlled switching mechanism, means responsive to the initiation `of a call from a calling line to cause' said automa'tically7 operating switching mechanism to entendV said calling line to" said dir'ectively controlledk switching mechanism, anrimfpulse fsender for said calling. line to set' said dilos ilo

las

iso

rectively controlled switching mechanism upon the terminals of the called line, trunk lines, and means responsive to the initiation of a call and the sending of a predetermined number of impulses to cause the release of said directively controlled switching mechanism and to further operate said automatically operating switching mechanism to extend said calling line to an idle trunk line.

8. In a telephone system, calling lines and called lines, impulse senders therefor, trunk lines, automatic switches comprising a line switch and a connector switch, means responsive to the initiation of a call and the actuation of the impulse sender of acalling line for extending the calling line through a line switch and the connector switch to the terminals of a called line, and means responsive to the initiation of a call and the sending of a predetermined number of impulses Jfrom the impulse sender for releasing` said connector switch and for interconnecting the calling line and an idle trunk line through the line switch and independently of the connector switch.

9. In a telephone system, a calling line and a called line, impulse senders therefor, trunk lines, automatic switches including a line switch and a connector switch, means responsive to the initiation of a call and the actuation of said impulse sender for interconnecting said calling` and called lines through said line switch and said connector switch, and means responsive to the initiation of a call and the sending of a predetermined number of impulses for causing a further operationotsaid line switch to connect the calling line to an idle trunk line and for releasing said connector switch.

l0. In a telephone system, telephone lines,

trunk lines, a link circuit, means including scriber controlled means including said link circuit for selecting an idle trunk circuit and connecting it directly to a calling line, and means responsive to said last means for rendering said link circuit available for use in other connections.-

12. In a telephone system, telephone lines, trunk lines, a link circuit, means for manipulating said link circuit to select a telephone line and include itself in such connection, means for manipulating said link circuit to select a trunk line and exclude itself from such connection, and means responsive to said last means for rendering said link circuit available for use in other connections.

In witness whereof, I hereunto subscribe my name this 28th day of June A D., 1920.

CHARLES L. GooDRUM.

DISCLAIMER.

1,541,347.-0har2es L. Goodmm, New York, N. Y. TELEPHONE-EXCHANGE SYS- TEM. Patent dated June 9, 1925. Disclaimer filed April 7, 1928, by the assignee, Western E lect/fic Company, Incorporated.

Hereby enters this disclaimer to the said claim of said Letters Patent which is in the following Words to Wit:

12. In a telephone system, telephone lines, trunk lines, a link circuit, means for manipulating said link circuit to select a telephone line and include itself in sucli connection, means for manipulating said link Circuitto select a trunk line and exclude itself from such connection, and means responsive to said last means for rendering said link circuit available for use in other connections.

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