US2405332A - Toll telephone diversion system - Google Patents

Description

ug. 6, 1.9496. H. H. scHRoEPPEL 2,405,332

TOLL TELEPHONE DIVERSION SYSTEM I Y Filed Nov. '7, 1944 2 Sheets-Sheet 1 Q8@ @www Aug. 6, 1946. H.' H. scHRol-:PPEL

` TOLL TELEPHONE DIVERSION SYSTEM 2 sheets-sheet 2 Filed Nov. '7, 1944 Patented Aug. 6, 1946 e UNITED STATES OFFICE p j Ard-2405,32 d y v` 4 v I l 'ront TELEPHQNE DIVRS'IGN -sYsTlEivi A Harold Henry Shrepl1el,GlenfRock, N. J., as-v l signor to American Telephone and Telegraph Y vtheir ,subscribers a v`special-1 arrangement of appa7 ratos by .which the .calling stations, Within the PBX -area xnaydial l.local -calls unrestrictedlyout 'de the :PBX area, but ,other calls -would .be dimay be completed through fthe -P'BX .equipment and through the. equipment of the ,associated central bilico without requiring the attentionlo ,the PBX-attendant. Although a eating statinwit'nin @hegPBX area may dial nlocal numbers without restriction, the arrangement ,was nevertheless -set upso as to automatically divert calls involving toll chargesfrom the ycentral oiiice to the PX.

.attendant so that sucnftoll callsmay be completed only bythe PBXattendant. lrlovveverfthe equipnnent required for this kind `of service is soexpensive instep-Aby-step telephone systems as .to

,be practically prohibitive Accordingly, fit is anoblectof this inventionto verted thePBX attendant. The ,local calls provide Simple end mearensire equipment in .step-by-jstep dial telephone systemsto automati- :caliy divert to the vPBX attendant certain types .o f calls, such astoll calls, While permitting .other types of calls, such as local calls, to be ,ma-deunrestrictedlyl n K In presen-t step-:by-step systems, Ithe central oiiioe lbattery has yits positive terminal grounded, but f t-he polarity'of the battery is reversed to =operate the 'call-ing part-ys 4message `register when a call :is-completed In .accordance with .the present invention, two p olarities of batteriesare employed v`at the Central omas, one yfor use in Acorr-ipleting `local calls ,andthe other for diventi-ng toll `{calls-to annattendant.- The battery fused vfor Completing flocal calls;may beone having -i-tsposi-tiveterminal grounded and the other battery may jbe one havingits negative terminal fgrou-nded. Arelay operated vbythe :negativelygronnded battery and nonoperated yby Ithe positively .grounded `battery will be Iern-ployedsfor the Acall -divertingr operations. y

invention will be fbet'ter understood fr on the more detailed description hereinaiterfollovl.- inggwhen read inconnection .with theaccompanylinademing-s mammal-lierre 3.1; illfntetles'sche- PBXservice have heretoforemadeavailablegto inatical'ly the general*featuresV of a -step-by-step telephone system employing the principles of fthe invention, and Fig. Zshows a more detailed dagrarn 'of the apparatus required to jpractiee the invernion,` 1

"fReferring to Fig, lj'of the drawings,l the PBX Oefand the central'ojliceCQ are shown connetted. to' each other in astep-by-step telephone 'yst'er'n, ''he'gcalling station designated l, which is ef dial type, is connected `through a line and after dialing the central oiilce code, ,connectedthrough a `first selector 3 `to toll diverting, relay apparatus' land trunk apparatus pg, the latterapparatusproviding a path over cable fconductorsto 'the vcentral* oilice C O. When the ophoesten@ il 1S thus connected to the-Central oflicegjline rider 1 isfcaused to iind thecalling trunk and dia'ltone is returned from the associ` lated' select or'j, VWhen. the' calling 'Station l dials number 0; for example, iti/vill 'be connected Yto the central o ice CO over the equipment already described, tn enthrough ii-rstselector 8 to the special service fof un'lsapparatus[Hl On the other hand, 'when the callingstation l dials No. 1,12, for example, "it will be connected to the central voiiice C() over the lequipment already described, then through the first Aselector 8, the Vspecial second selector '9 and the s pecialithird selectorlil to the recording completing trunk apparatus lf2. The calling'jstationmay dial number '0, for example, to reach the special apparatus i1 So that the central bceperator ymay then complete a lshort haul toll lca'll. Number 112 may be dialed by the callingstation' 'l to'reach .the Central Lofce recording "completing apparatus l2 so `that the centraliofceoper'ator may .then ,complete a long dis- .;tanceicall'to vanother city, for example. However, according ,to the 'present invention, the dialing ofhnunibers 0 .or 112 Will actuate the apparatus H or |52 so as to-automatically switch the calling lpartys .line at the PBX toll diverting apparatus '9 togtheaiilenfnls trunk apparatus 6, By this arrangement'thertoll or :long distance calls `will be controlled by the PBX attendant so that only those calls that-are authorized by theattendant will be completed by the .attendant through :the centralveiice CO. The toll diverting apparatus will 4vremain undperated by ordinary local calls 4fronrt'he calling station so that such-'calls may be completed throughjthecent-ral oiiice f'CG inthe usual manner. lBut *the toll divertinggfeature will come 'intopplay only jin response `to predetermined dialedcodes emanating f-rom'the Ycalling station iI such as toll or long distance calls, unless sanctioned by the PBX attendant.

The essential equipment in use at present in step-by-step ofces may be understood by considering the arrangement of Fig. 2 When the calling station 2| dials a code to complete a local call. The apparatusl labeled 4,6, Il andv I2 `in Fig. 1 is shownin .greater detail in Fig". 2. l When the calling station 2| dials a local number, the

calling station,2l will be connected to the tipand ring conductors T and R of a trunk leading to .the central cfce CO, throughequipment of the PBX oice, the PBX equip ment including a line finder 22, line finden andgrst selector relay apparatus 23, a first selector 24,;the upper armature of a relay such as OP andtheback contacts of these armatures, and trunk'equipment 25 which controls the trunk having tip ring conductors T and Rgextending to the central Omce CO.VV A t the central office CO, the connection of the calling station' 2 ll continues 'ov`er' a line lindert. 721, line finderfarld'rst'relecto'rrelay apparatus 28, a rst selectorZS; and then through second and thirdswelectois'if required (not shown) toai connector, selectorfconnector or 'intero'ilice repeater 3Q'. Inthe device; the eircuitcontinues over the windings of relay LR1 to battery 32 and ground .33: The; linerelayLRi Will'then operate and in 'turn operate 'relay- SLi Ato 'ground the sleeve terminal S s oa's' t'hold the'coniiecjojo the'patnwiuf bef continued through 'me line finder2'l,- thejlih iinder 'and iist'selector" relay apparatus 28';then through'the irst selector "38,

the armatures ofbabffreiay-Cuz'adtheir'back contacts, the windingso'i line 'relay'LRz Vto bat- ',tery'42'ii'dground'43. Itis notedthat battery 42 is poled direction which is opposite to that of battery 32, the negative pole of battery l2 being 'grounded at 43. The function of battery 42 'Will be explained presently.' The operation of `line relay LR2 will occurupon-fthe completion of the circuit just traced'and it in turn will cause relay SLa to operate over an obvious pathprovided' by the armature andv make contact` of the linev relay LRz. Relay SLz Will connect ground to the sleeve terminal of the-first selector 38 and the line ncler and first selector relay apparatus As soon as the trunk apparatus. 25 atthePBX oilice. is seized byY the callingporlfyfslina ground 44 willbe connected to the sleeveterminals of the first selector 2 4 over a circuit which Vin- 1 cludes the makefbeiore-brealr vcontacts associated jwith. themlovver -inner. armature of relay OP. Moreover, as soonfasthe Aiirst selector 3sat the central yoilice COis seizedfa circuit Will be .completed to theY operating YWinding of polar relay -line' relay LRa.

relay LRz, the upper armature and back contact of cut-oil relay CU2, the tip terminal of first selector 38, then through the line iinder and rst selector relay apparatus 28, the tip terminal of line nder 21, then over the tip conductor T of the trunk, then through the trunk apparatus25 at the PBX oce, the right winding of choke 'I' I, the right or operating winding o frelay T to ground 44. The current owing from battery 42 is in a direction that will cause relay T to become operated. Relay T will then be locked in its operated position over a circuit which includes ground 44, the left or holding winding of relay T ka'n'clits make contact and armature, the Winding of relay OP, battery 45 and ground. Inasmuch as the Winding of relay OP is included in the locking circuit of relay T, relay OP will be operated at the same time that relay T becomes locked.

In response to the operation of relay OP,.the previouslydescribed path between'the rst se-v lector -24 and the trunk conductors T and R will be opened at Athe back contacts of the upper armatures of relay OP. The path tothe calling station 2l Will now be transferred tothe PBX attendants trunk apparatus 6. This diversion of the callingstation 2| will cause'the line relay LRn vof :the PBX attendants trunlr apparatus Y6 to become operated, the operating circuit including battery 52, the right Winding'of A`relay LRsft'he right'outer armature and back contact of'vcut-offl relay CUa, the inner upper Amake contact and'armature of-'relay OP, the .ring terminal of rstselector 24, through apparatus 2,3, the ringterminalof line finder-22, calling station 2l', the'tip terminal of line nder 22, the apparatus 23,v the tip terminal of first selector 24, the upper outer armature and'make contact of relay OP, theleft of line relay LRs,the left back contact fand armature of cut-off relay CUS and ground. The operationv of line relay LRc in turn operates relay CH over an obvious path completed through the right make 'contact and armature' of Y 'I'he closure of the make contact of relayCH connects ground through the lower -inne'rarmature and make contact of relay- OP T. The latter circuit may'be traced to include ground43`, battery 42, they lower winding of line tothe sleeve terminal of rst selector 24 to hold Vthe rst selector 24 in itspresent position? The closure of the make contact of relay CI-I will also provide a holding path for relay OP through the lovverr outer'make contact and armature of relay OP.' The operation of line relay LR6 also completesan obvious path over its left armature and make contact to illuminate theV PBX attendants lamp LL. This Will signal the PBXv attendant and the attendant may then obtainthe necessaryiniormaton from the calling station to complete the desired call. The attendant's set 60 may be connected to the calling station 2| merely by inserting plug PL into jack JK. When this happens thecut-of relay CUa will become operated over an obvious path completed through theground contact 6| of jack JK. Relay LRa vwill release in response to the operation of relay CU2.. The release of relay LR: will extinguish lamp LL, .but ground at the inner right armature ofrenyi cue'wiuhoid relay CH operated.- The PBXattendant may then connect the calling station tothe central oce CO, but'the details of the interconnecting circuit are not shown.

The latter circuit to the central officeyCO may be completed through jack JK or through a similar jack multipled` thereto.V i `It -will be clear that upon the operation o relay OP as already'described hereinabove, -the trunk equipment at the PBX station will be released so as tobe available 'for another call. At the same time line relay LRz will be released and relay LRz will in turn release relay SI12. The equipment at the central ofce CO will therefore also be available for another call. The release of the trunk equipment 25 will also disconnect ground M from 'the operating windinglof relayvT, whereupon relay T will release. Although relay T releases; relay 'OP and the 'first selector 24 will be held Aoperated by ground provided by the ar-mature Aof relayjCI-I. Relay lOP' will be held -operated until the calling Vstation `2l has completed the call. When the PBX attendant removes the plug from jack JK 'or its `multiple,relay 'CUa will release, thereby releasing relay CH as well as relay OP. The equipment at the PBX station will be returned to normal and will now be ready for another call.

The relay T will be opera-ted when it is connected to battery '42 but will remain unoperated when it is connected to battery 32. This is due to the fact that relay T is of the polar type and will readily distinguish between oppositely vpoled batteries 'such as'SZ and 42. Hence local "calls of the usual type will fail to operate the toll diverting relay equipment# at the PBX station, but other vcalls will operate the toll diverting equipment 4 and thereby call in the PBX attendant. It is noted that the operation of the toll diverting equipment d will promptly break the circuit l between the calling station 2l and the central Ofr'lCe CO.

Likewise, when the calling station 2l dials number H2, the connection to the central oice CO will be completed by the same path as already considered for the case when number 0 is dialed. At the central office CO the path will then include the line iinder 2l, the line iinder and first selector relay apparatus 28 and the first selector t8 to the recording completing trunk apparatus i2. The path through the latter apparatus I2 will include the primary windings of repeating coil 69, the windings of line relay LRA, the laments of lamp LP, battery 62 and ground 63. The line relay LR4 will become operated, in turn operating relay SLi. Relay SL4 will then extend ground to the lirst selectors 2Q and 68. It will be observed that battery 62 is of the same polarity as battery i2 and hence relay T of the toll diverting relay apparatus l will be operated as soon as battery 62 is connected to the" tip conductor T. The connection of the calling station 2| to the central office CO will therefore be broken, but will be diverted to the PBX attendants trunk circuit 6, in the manner already described hereinabove.

Both batteries d2 and E2 are shown connected to the tip side T of the trunk interposed between the PBX station and the central office CO. This is important for the connection of either battery G2 or 62 will not operate the subscribers message register (not shown) on calls completed by the PBX attendant. The reversal of battery 32 cannot be used fcrtoll diversion because such a reversal would operate the message register falsely and would, moreover, cause the equipment to respond falsely to local calls. Consequently a separate battery, such as 42 or 62, of a polarity which is opposite to that of battery 32, is important in the practice of this invention.

It will be observed that the choke coils TT are bridged across the trunk conductors T and R in series with a condenser X. This bridging circuit will present a large impedance to talking curren-ts so that-'such currents wil-lnot be absorbed by Lthe bridging elements. The l'condense-r iK will also act to block the flow of direct currents-between-the left coil 'o'f impedance device and the operating winding of -re-lay T. v

With lthe above-described arrangement the local :calls by the =calling station 2 Iwill reach vthe central oice -CO through the PBX equipment and may bepo'mpleted without lattracting the attention ofthe PBXoper-ator. Y Other calls, Isuch as toll calls, will reach the central `ollice ACO but they will be automatically diverted to the PBX attendantbefore they are Acompleted by 'the centrai cnice operator. Y

While this 'invention has been showt-rand described ini-certain embodiments merely for illustratv-e purposes, the general principles of this invention may be applied to other andwidely varied organizations without departing Mfrom 'the spirit ofthe invention' and the 'scope of the Jappended claims. l

What is Aclaimed:

l. In a lstep-by-step telephone system, the .conn hina-tion of a l'dial telephone subset, aline to which said dial vsubset maybe connected, a polarrelay connectedv to said line, two voripositely poled grounded batteries, means responsive to a first predetermined code ydialed by said subset to cennect the positively grounded battery to said line, said positively grounded battery being unable to transmit current through the winding of said polar relay to operate said polar relay, means responsive to a second predetermined code dialed by said subset to connect the negatively grounded battery to said line so as to operate said polar relay, and means responsive to the operation of said polar relay to break the connection between said subset and said line.

2. In a step-by-step telephone system, the combination of a PBX serving one 0r more dial telephone stations within its area, a central ofce which may be connected to said PBX, a positively grounded battery and a negatively grounded battery at said central oice, a polar relay at said e PBX, means responsive to a rst predetermined code received by said PBX from a dial station within its area to establish a circuit from said dial station through said PBX to said central oflice and to connect the positively grounded battery to said circuit, said polar relay being connected to said positively grounded battery but remaining unoperated, means responsive to a second predetermined code received by said PBX from a dial station Within its area to establish a circuit from said dial station through said PBX to said central oice and to connect the negatively grounded battery to said circuit so as to operate said polar relay, and means responsive to the operation of said polar relay to break the circuit between said PBX and said central ofce.

3. In a step-by-step telephone system, the cornbination of a PBX serving one or more dial telephone stations within its area, a central oiice which may be connected t0 said PBX, a positively grounded battery and a negatively grounded battery at said central oflice,'a polar relay at said PBX, means responsive to a first predetermined code received by said PBX from a dial station within its area to establish a circuit fromV said dial station through said PBX to said central office and to connect the positively grounded battery to said circuit, said polar relay being connected to said positively grounded battery but remaining unoperated, means responsive to a second predetermined code received by said PBX from ya dial station within its area to establish a circuit from said dial station throughsaid PBX to said central oflice and lto connect the negatively grounded battery to `said circuit so' as to operate said polar relay, and means responsive to the op eration of said polar relay to signal the PBX and to prevent the completion of any call from said dial station through said central oice.

4. In a step-by-step telephone system, the combination of a PBXserving one or more dial telephone stations Within its area, a central oiiice which may be connected to said PBX, a positively grounded battery and a negatively grounded battery at said central office, a polar relay at said PBX, means responsive to a first predetermined code received by said PBX from a dial station Within its area to establish a circuit from said dial station through saidv PBX to said central office and to connect the positively grounded batteryvto said circuit, said polar relay being coni nected to said positively grounded battery but remaining unoperated, means responsive to a second predetermined code received by saidPBX from a dial stationwithin its area to establish a circuit from said dial station through said PBX to said central office and to connect the negatively grounded battery to said circuit so as to operate said polar relay, and means responsive to the Y 8 operation of said polar relay to break the circuit between the PBX and said central oilce and simultaneously to signal the PBX.

5v. In a step-by-step telephone system, the combination of a calling station of the dial type, a PBX to which the calling station is connected, a central oice, a line having tip and ring conductors interposedbetween the PBX and the central office, a positively grounded battery and a negatively grounded battery at the central oce, a polar relay connected to the tip conductor at the PBX, means responsive to a predetermined code dialed by said calling station to seize said line and connect the positively grounded battery to said tip conductor, the polar relay remaining unoperated when the positively grounded battery is connected to said tip conductor, means responsive to another predetermined code dialed by said calling station to seize said line and connect the negatively grounded battery to the tip conductor, the polar relay being operated when the negatively grounded battery is connected to said tip conductor, and means responsive to the operation of said polar relay to disconnect the calling station from Said line and to simultaneously signal the PBX.

HAROLD HENRY SCHROEPPEL.

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