US1945466A - Telephone system - Google Patents

Description

Jan. 3Q, 1934 H. M. FRIENDLY v 1,945,436

TELEPHONE SYSTEM Original Filed Sept. 23, 1921 9 Sheets-Sheet l 0 0 /OZ /0/ o Inveniur- ALjgs.

Jan 3%, 1934. H. M. FRIENDLY L fi TELEPHONE SYSTEM Original Filed Sept. 25. 1921 e Sheets-Sheet 2 m EN Ail a,

Jan. 30, 1934- H. M. FRIENDLY TELEPHONE SYSTEM Original Filed Sept. 23, 1921 9 Sheets-Sheet 3 Inveniur- Herb erL-Flfiiandl Jan. 30, 1934. H. M. FRlE NDLY 1,945,466

TELEPHONE SYSTEM Original Filed Sept. 25, 1921 9 Sheets-Sheet 4 All] a Jan. 30, 1934- H. M. FRIENDLY TELEPHONE SYSTEM Original Filed Sept. 23, 1921 QShe'ts-Sheet 5 1.. i MU Pa m w QQV m m Mm...

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TELEPHONE SYSTEM Original Filed Sept. 23; 1921 9 Sheets-Sheet 6 Invantur- Jame 3 0), 1934.

H. M. FRIENDLY TELEPHONE SYSTEM Original Filed Sept. 23, 1921 9 Sheets-Sheet 7 MEN h 5%.

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I NB Invenmr- Herb eri-PIfiiendl 9 Sheets-Sheet 8 wmw QM m hmm 9% H. M. FRIENDLY TELEPHONE SYSTEM Inveniur- Hath efi-P'I-Fhendl $25, $31 I]: M Ear M $15:

mun N N Q NQ mm Jam 35 9 1934 Original Filed Sept. 25, 192-1 a z a z m M w L 9% B wwv mmw RN Rm H h/ 5% m 3M EN EN hum NAN N z I 4 wk. TU nu m w A RN M a Patented Jan. 30, 1934 UNITED STATES PATENT OFFICE 1,945,468 TELEPHONE SYSTEM Application September 23, 1921, Serial No. 502,626

Renewed April 9, 1926 127 Claims.

affording of operative conveniences to users and benefits to the operating concern which have been heretofore unknown.

The invention in its specific form chosen for the illustration herein, contemplates a.so-called two-wire common battery automatic telephone system as has been widely used, the present invention necessitating novel departures from equipments heretofore known so far as I am aware, in attaining the new objects, while retaining certain operative functions which are known.

The exampled form of the present invention chosen to illustrate it contemplates its adaptation to a comprehensive four-digit automatic telephone exchange system. However, the present invention is more particularly directed to that part of a comprehensive automatic telephone exchange system as relates to groups of subscriber's lines and to toll and special service.

In comprehensive automatic exchange systems there are various classes of subscribers, each demanding more or less special service and presenting varied operating conditions. For example, certain subscribers generally termed individual subscribers, have a single or isolated local line used for in-going and out going trafllc between the subscribers premises and the main exchange. Other subscribers have a plurality of such lines, known as a group. Where a group of lines serves a subscriber it has been a practice heretofore to list one telephone number so that if this number is called the group of lines will be reached and a first idle one thereof ,seized and rung upon, so thatthe operation so far as the calling subscriber is concerned is the same when calling a subscriber having an individual line, or a group of lines serving his trafllc.

Where a group'of lines extend to the premises of a subscriber theyusually terminate in a private branch exchange switchboard, the calls being answered by an attendant or operator, and then extended to any desired local telephone terminating in the private branch-exchange switchboard. Under this plan of operation, when the operator is absent, at night or on holidays, for example, it has been a practice to connect certain ones of the lines of the group to certain local telephones so that a call coming in over one of the thus connected lines of the group will signal the connected telephone directly, and may be answered by anyone near the concerned local telephone. Going further, it has been a practice to specially list certainptelephone numbers which are comprised in the group, or which may not be comprised in the group but are in common relation therewith in the main ofilce by reason of the bank contacts corresponding to special non-group-selecting connectorbank numbers listed being in multiple relation with the corresponding connector bank contacts leading to the concerned line (or lines) of the group, so that as a matter of fact, the concerned line is reachable by calling the regular listed telephone number accessible to a group-selecting connector, or by calling a specially listed telephone number accessible to a non-group-selecting connector. The above practice refers more particularly to private branch exchange subscribers having one or more employes available at one or more specific telephones in the private branch exchange at nights and on holidays, for example and, therefore, affords a means of directing a call at these times to the special telephone.

Due to the inherent characteristics of the connectors heretofore known so far as I am aware (such as connector C in Fig. 4 of my Patent No. 1,506,054, granted Aug. 26, 1924) which automatically select a non-busy line of a group when the telephone number indicative of the entire group is called, confusion is often entailed. For example, if the local telephone connected to corresponding with the specially listed telephone number comprised in the group is busy, and therefore, the line of the group corresponding with the specially listed telephone number is guarded against intrusion, the group selecting connector concerned in a call transpiring will automatically select the first non-busy line of the group following. This will either signal a telephone not wanted on the premises of the subscriber or it will seize a ,trunk line that has no connected extension from the private branch exchange switchboard-and, therefore, will not be answered. Of course, where auxiliary or special numbers are assigned in non-group selecting connectors corresponding to specific lines comprised in the groups as has been referred to,

specific line of the group is busy an alternative line of the group will be selected unless, of course, the line is the last line of the group. The latter would only be possible where a single special number is connected for night and holiday use.

a. The present invention contemplates, among other novel functions, and. the equipments for effecting them, a group-selecting connector which is normally a non-group-selecting connector, but which is transformed into a group-selecting connector, consequent to the first bank position of a subscribers group being encountered in a call from a subscriber's station, regardless of whether the line leading therefrom tests busy or not.

From this it will appear that the connector of the present invention referred to will not rotate as a group-selecting connector if a telephone nber specific to a line of the group other than the line occupying the first bank position of the group is called. The present invention then, permits of any of the lines occupying bank positions in a group other than the first bank posi-= tion thereof being connected to a local telephone ina private branch exchange and insures that a call directed to the listed telephone number corresponding to the specific line of the group will attain connection to the desired local telephone or will give a busy signal to the calling party.

Auxiliary to inter-subscriber switching, comprehensive exchange systems in nearly all cases contemplate the switching of toll lines to the local lines leading to the premises of subscribers. This switching is, in nearly all cases, controlled or effected by an operator located at a toll switchboard situated within the confines of the exchange district, which shall betermed the exchange toll operator and the exchange toll switchboard, respectively, or at some remote point wherein the switching connection is established by controlling automatic switching equipments over the toll line from which the connection to the subscriber is desired.

b. Depending upon the traflic, various means for rendering this service to the subscribers have been employed. Where the traflic of a toll nature is very light and the local traflic is also light and not apt to interfere seriously with the toll traflic, toll calls are routed over the same lines from the main exchange to the premises of the subscriber as are used for local tramc, though it has been a practice to provide specific switching apparatus in the main exchange for attaining connection to the local lines through convertible connectors in common with the, local apparatus directed by subscribers.

0. Another method which has been employed is that of providing an independent line between a spring-jack on the exchange toll switchboard and the subscriber's premises reserved exclusively for toll service to the subscriber and for the use of the subscriber in calling the exchange toll operator. These shall be termed manual toll loops. The exchange toll operator, under this method of operation, extends the call by means of a switching cord-pair.

d. Another method which has been employed is that of providing an independent line from a subscribers premises to a toll automatic switching system, independent of the local automatic switching system, whereby the exchange toll operator can call over the independent line to the subscriber automatically through a cordpair, through the agency of a dial or other equivalent calling device. These shall be termed automatic toll loops". Systems 0! this kind have, in cases, been accessible not only from the exchange toll switchboard located within the confines of the exchange district, but also accessible to toll operators at toll switchboards located remotely, wherein the establishment of the connection is controlled over the toll line from which the connection to the subscriber is desired. The latter shall be termed the remote toll operator and the'remote toll switchboard, respectively.

An undesirable feature involved in the methods set forth under paragraph c'f is that the exchange toll operator upon receiving the call for the subscriber from a distant point must know ofbhand that the called subscriber has a special toll loop, so the call can be completed through a switching cord-pair. in view of the fact that in many cases calls are given by calling parties by number, and that it is quite impossible to mentally retain the information relating to all subscribers in large systems and that it is not always convenient to consult an authentic special directory, the calls are very often routed over the regular exchange local lines to the subscribers, causing annoyance. Again, these manual toll loops not being accessible to operators located remotely, will mean that all remotely completed calls to a called subscriber over the toll lines will reach the subscribers premises over the regular exchange local line and, as before stated, cause annoyance.

An undesirable feature involved in the method set forth under paragraph d is that the exchange toll operator on receiving a call from a distant toll station for a local subscriber must know that the called subscriber has a special automatic toll loop. Also, the remote toll operator calling for the subscriber automatically must know off-hand that the called subscriber has a special automatic toll loop, the same as where the toll loop terminates on a springjack on the exchange toll switchboard reachable from the calling toll line through a switching cord-pair. So it is necessary for the remote toll operator who may be calling over a toll line automatically, to have this information or it will be completed under control of the remote toll operator over the regular exchange local line (or one of the exchange local lines) of the subscriber, causing annoyance.

e. The present invention, wherein it relates to independent toll loops (manual and automatic) to the premises of local subscribers comprehends means for automatically apprising the calling .toll operator (located in the main exchange disthe group accessible to the group-selecting connector used by the local subscribers in calling and also by the toll operators, which shall be termed the exchange toll loop", but that this exchange toll loop is only accessible to a toll operator calling through the special toll selectors, and is not accessible to a local subscriber calling through the local selectors.

j. A further function of the group-selecting connector referred to in paragraph c is that if the toll operator receives the tone indexing that the called subscriber has an exchange toll loop accessible through the group-selector connector then functioning, and also receives a' tone auxiliary thereto indicative that the exchange toll loop is busy, the toll operator can, by sending digit 1, cause the group-selecting connector to forthwith start functioning as a group-selecting connector and seize the first disengaged local exchange line. If the exchange toll loop is not busy the connection can be completed normally, but the connector will not function as a groupselecting connector, when reached from a toll selector, unless the digit l is sent to initiate its functioning as a group-selecting connector regardless of the busy or idle state of the exchange toll loop primarily called.

g. A further function of the group-selecting connector referred to in paragraph f is that should the toll operator call an intermediate line of a group it will not function as a group-selecting connector unless digit 1 is sent to initiate such functioning, regardless of whether the intermediate line called is idle or busy.

h. A further function of the group-selecting connector referred to in paragraph 9, is that if the toll operator, upon calling an intermediate line of a group, receives a busy tone and the operator then sends the digit "1, causing the connector to function as a group-selecting connector, whereupon it seeks an idle line of the group of local lines, but fails to find a disengaged one, upon engaging the last tank position of the group applies the customary busy-tone indicative that there are no idle lines in the group. The operator can, by sending an additional digit 1, cause the connector to be released to normal position. The selector co-operating with the connector still maintains its seizure and thus enables a call to be completed through the connector to a line of the group last concerned, or to any other line accessible to the connector, by calling two digits, whereupon the connector will function as if it has primarily reached the last line called, and had not been released. A further function of the group-selecting connector, effective when it is co-Operated with a toll selector, is that when it is seized by the cooperating toll selector, it applies a specific tone audible to the calling toll operator indicative that the connector is seized, and moreover, that it is at normal position, since the said tone is disassociated consequent upon the first off-normal movement of the shaft.

2'. In view of paragraphs e and f it will appear that, if through inadvertence, the toll operator ignores the fact that the called sub scriber has a manual toll loop terminating in a springjack on the exchange toll switchboard, a specific tone will be applied audible to the calling operator upon the connector attaining the called bank position corresponding to the called line, regardless of its busy or idle state, prompting the fact there is such a toll loop, so the connection can be taken down and properly routed.

a. It will appear that the present invention enables ihe toll operator, wherever located, to reach the called subscriber over his telephone number listed in the general subscribers directory and it will also appear that this exchange toll loop is barred against seizure by a local subscriber calling the subscriber having the exchange toll loop, through local selectors; such calls being directed to a local line of the group.

It. Another connector contemplated under the present invention is a non-group-selecting connector used for completing a connection to a subscriber's local line, that will function to pro- Ject a specific tone audible to a calling toll operator indicative that the subscriber called has a manual toll loop terminating in a springjack on the exchange toll switchboard, or has an automatic toll loop, perhaps, which can be reached through an auxiliary automatic toll exchange. The tone function referred to is dependent in a measure upon functions of the toll selector cooperating with the connector and, therefore, the said tone will not be operative to local subscribers calling through local selectors to the connector.

Z. The shaft of the connector referred to in the last foregoing paragraph can be released to 'normal position under control of the toll operator' if the line selected, called through a toll selector, tests busy or the connector seizes. This releasing cannot be effected by a local subscriber calling through a local selector. Of course, the tone thus appliedmay index any other condition relating to the called subscriber, such as to prompt the calling operator to refer to the credit record, etc. In fact it is contemplated, as will appear, to have a plurality of tone sources interchangeably connected in relaiion to the subscribers equipment so that various tones will be connectible to prompt any single one or a plurality of specific facts concerning the called subscriber, and other callable subscribers.

m. A function of the present invention relates to the toll loops referred to in paragraphs e" and I, wherein it the telephone terminating the exchange or automatic toll loop is removed from the switchhook when the line is normal in order to initiate a call to the toll switchboard, an outgoing call, for example, it will cause a local interofilce general traffic trunk to be seized and the call automatically directed and completed to the recording position of the exchange toll switchboard, without special operation on-the part of the calling subscriber. It will thus appear that where an exchange is made up of a plurality of main-branch offices the independent exchange and automatic toll loops of subscribers will be connec' ed into the same main-branch oflices as the local lines of the concerned subscribers.

Other novel functions and features, as well as the invention itself, will appear.

In the accompanying drawings:-

Fig. 1 shows an automatic telephone L leading into a lineswitch LS, and the latter in 'ommon with other lineswitches (not shown) have access to a first selector FS. The first selector F8 in common with other first selectors (not shown) have access to second selector SS. The second selector SS, in common with other second selectors not shown) have access to connectors A and F.

Fig. 2 shows a group-selecting connector A which has access to cooperating bank contacts.

Fig. 3 shows two local automatic subscribers lines and an exchange toll loop accessible to connector A.

Fig. 4 shows a toll selectorB which has access through cooperating bank contacts with connectors A and F.

Fig. 5 shows an operators switching cord-pair C adapted to cooperate with springjack D leading to toll first selector E. Selecor E in common with other first selectors similar to it (not shown) have access to second selector B.

Fig. 6 shows a non-group selecting connector F which has access through cooperating bank contacts to two subscribers local lines.

Fig. '7 shows a normal-level selector I terminating an inter-oflice trunk. Through its normal level it has access to equipments H located on a recording position of the exchange toll switchboard. Through its first level, and other levels not shown, calls can be forwarded in the direction of called local subscribers lines.

Fig. 7A shows a novel mechanical detail 01' two companion relays in Fig. 7 wherein one of the relays is shown operated, restraining the other.

Fig. 8 shows a schematic arrangement of two banks of contacts, such as are shown cooperating with connector A of Fig. 2, but in more detail. The bank contacts designated J correspond to the bank contacts shown cooperating with the said connector A, while the banks designated K represent one of a plurality of banks which cooperate with connectors similar to said A of the connector group. It will thus be clear that the bank contacts shown in the bank cooperating with said A are in multiple relation respectively with the contacts of banks cooperating with a plurality of respective connectors similar to said A of the group. The conductors leading from the respective multiplied contacts located in cor= responding relation to the respective connectors 25 of the group lead to terminals from which the connections contemplated under the present in-= vention can be made and altered from time to time without-consideration of each bank individually.

Fig. 9 shows a toll line leading from a springjack L on the exchange toll switchboard to a remote toll station telephone T9.

Fig. 10 shows a manual toll loop leading from a springjack M on the exchange toll switchboard to a subscriber's toll telephone T10.

Fig. 11 shows the arrangement of the figures concerned in a call from the exchange toll switchboard to toll loop telephone T23 or to local telephones L12 and L24.

Fig. 12 shows the arrangement of the figures concerned in a call from local telephone L to local telephones L12 -or L24.

Fig. 13 shows the arrangement of figures concerned in a call from local telephone L to local telephones L6 or L6.

Fig. 14 shows the arrangement of the figures concerned in a call from toll loop telephone T23 to the exchange toll switchboard.

Fig. 15 shows the arrangement of the figures concerned in a call from the toll switchboard to local telephones L6 or L6.

Fig. 16 shows the relative location of the sets of bank contacts in the bank cooperative with connector A with respect to the bank positions thereof.

Referring to certain of the various figures:

In Fig. 1, L is a usual series type of automatic telephone having a calling device 102 of the general class as shown in British patent to Dicker No. 29,654 of 1910. The lineswitch LS is of the general class as shown in U. S. patent to Lamb, No. 1,193,160, granted August 1, 1916. The first selector FS is of the general class as shown in U. S. patent to Keith and Erickson, No. 815,321, granted March 13, 1906, of course, modified in mechanical and circuit details to operate on the well known so-called two-wire principle and in accordance with the present invention. The second selector SS is similar in detail to first selector FS. In this connection it-may be stated that tele-- phone L, lineswitch LS, first selector FS and second selector SS, may for the purposes of elucidating the present invention, be considered as telephone A, lmeswitch C, first selector E andv Frank Newforth, April 13, 1915, numbered 13,901.

In Fig. 2 the novel group-selecting combination local and toll connector A is 01 the general class as shown in U. S. patent to Keith and Erickson, No. 815,176, granted March 13, 1906, or course, modified in mechanical and circuit details to operate on the well known so-called two-wire principle and in accordance with the present invention.

In Fig. 3 telephones L12, L24, T23 and E3 may be considered similar in detail to telephone L. Lineswitch LS3 may be considered generally similar to LS. Relays 301 and 302 may be considered as representing lineswitches similar to LS. Lineswitch LS3 may be considered similar in detail to iineswitch LS. First selector PS3 may be considered similar in detail to selector SS.,

Repeater R3 is a novel device for localizing the battery supply to a calling telephone and for repeating impulses to switches interlinked in the direction of the called line.

In Fig. 4. the novel. toll selector B, adapted for cooperating with combination local and toll connectors A and F, belongs to the general class to which selector FS belongs.

In Fig. 5 the toll first selector E belongs to the general class to which selector FS belongs, and is well known in the art.

In Fig. 6 the novel non-group selecting combination local and toll connector F belongs to the general class to which connector A belongs. Telephones L6 and L6 may be assumed similar in detail to telephone L.

In Fig. 7 the novel normal-levelselector I belongs to the general class to which selector FS belongs. Connector CS7 may be assumed similar in detailto connector F. lelephone L? may be assumed similar in detail to telephone L. Relay 700 may be assumed to represent a lineswitch similar in detail to 18.

In Fig. 9 telephone T9 is a well known type of bridging local battery telephone.

In Fig. 10 telephone T10 is a well known type 01' non-automatic local battery telephone.

To simplify the drawings and descriptions, battery and ground are shown as independent sources throughout, wherever applied, but it is to be understood that the system is of the common battery type. In the descriptions, when a circuit is traced to a winding, the opposite terminal of which is shown applied .to grounded battery or to ground, the described circuit is to be considered as traced to ground through the winding to bats tery, or direct to ground as indicated.

The performance of the equipments will be detailed under different assumed operative conditions, having in mind that the equipment elements may be, and in fact, ordinarily would be variously organized in the assembly of a system.

Referring to the accompanying drawings:-

With reference to Fig. 13, it will be assumed that a call from telephone L is to be extended to called telephone L6, the telephone number 01 which is 1212". Upon the calling subscriber. re-

'moving the receiver from the switch-hook of telephone L, lineswitch LS will automatically seize a trunk to a disengaged first selector FS. Upon sending the first digit 1 by manipulating the calling device 102 in accordance therewith, selector FS will step its wipers into alignment with the first level of its bank contacts and automatically rotate-in and seize a trunk leading to an idle second selector SS. Upon sending the second digit 2".selector SS will step its wipers second selector F shown in the patent reissued to into alignment with the second level of its bank "wherein the receiver at telephone L6 is removed contacts and automatically rotate-in and seize a trunk leading to an idle connector F.

A circuit can now be traced from the upper winding of relay 601, make-beiore-break spring 602, conductor 603, wiper 101, conductor 102, wiper 103, conductor 104, wiper 105, conductor 106, through receiver of telephone L, conductor 107, wiper 108, conductor 109, wiper 110, conductor 111, wiper 112, conductor 113, make-before-break spring 604 to the lower winding of relay 601, relay 601 actuating. A circuit can now be traced from the winding of slow-releasing relay 606 to grounded armature 607, relay 606 actuating. Grounded armature 608 applies its ground to conductor 609, wiper 114, conductor 115, wiper 116, conductor 117, wiper 118 to the winding of cut-off relay 119 of lineswitch LS, maintaining the said lineswitch in the well known manner.

Upon the calling subscriber sending the third digit 1, relay 601 will de-actuate and re-actuate one time. Ground from armature 607 will be applied to armature 612, armature 613, series winding of slow-releasing relay 614, winding of vertical magnet V6, sideswitch wiper 615 to grounded battery, causing relay 614 to actuate, and to operate the vertical magnet one time to step the shaft carrying wipers 616 to 619 (inclusive) into alignment with its first bank level. Incidental to the operation of relay 614, grounded armature 620 engages make-before-break spring 621 and applies ground to the winding of private magnet P6, energizing it preparatory to permitting the sideswitch wipers 615 and 622 to advance into their second position. Upon relay 614 deactuating its period after the opening of the energizing circuit including the winding of vertical magnet V6, the sideswitch wipers 615 and 622 will advance-into their second position.

Upon the calling subscriber sending the fourth digit 2, relay 601 will deactuate and re-actuate' two times. Armature 607 will apply its ground two times over a circuit including armature 612, armature 613, winding of relay 614, armature 624, winding of rotary magnet R6, sideswitch wiper 615 to grounded battery, causing relay 614 to actuate and operate the rotary magnet two times to step the wipers 616 to 619 into engagement with bank contacts 625 to'628 respectively. Upon relay 614 de-actuating its period after the opening of the energizing circuit including the winding of rotary magnet R6, the sideswitch wipers 615 and 622 will advance into their third position. A circuit can now be traced from ground, sideswitch wiper 622, winding of relay 629, sideswitch wiper 615 to grounded battery, relay 629 actuating. A circuit can also be traced from ground sideswitch wiper 622, wiper 617, bank contact 626 to the winding of cut-ofi relay 630 of the lineswitch similar to LS associated with the line leading to L6, disassociating it from the telephonic conductors of the said line in the well known manner.

A circuit can now be traced from grounded interrupted ringing current source G6, armature 631, armature 632, armature 633, armature 634, wiper 619, bank contact 628, signal bell at telephone L6, bank contact 627, wiper 618, armature 635, armature 636, armature 637, armature 638, inner winding of relay 640 to grounded battery. The signal bell 641 of telephone L6 which includes condenser 642 will be operated, but the characteristic of relay 640 is such that it will notice operatively energized by the said ringing current. However, upon the response of the called party,

from the switchhook, aconductive circuit can be traced from grounded ringing current source G6 over the traced path, now including the receiver or telephone L6. Relay 640 will operate. A locking circuit for relay 640 can now be traced from its outer winding, armature 643, conductor 644 to grounded oft-normal spring 645. Off-normal spring set 0N6 is adjusted to closeits contacts upon the first oil-normal movement 01 the shaft carrying wipers 616 to 619.

A circuit can now be traced from upper winding oi. relay 646, conductor 647, armature :636,

telephone L6, armature 633, conductor 648, lower winding of relay 646, armature 643, conductor 644 to grounded spring 645, relay 646 actuating. Incidental to relay 646 actuating its armatures 649 and 650 engage make-before-break springs 602 and 604 respectively, and thereby reciprocate therelationship oi the windings of relay 601 to conductors 603 and 113 as primarily existing. A telephonic circuit now exists from the calling telephone L to conductors 603 and 113 and from conductor 603, condenser 651, conductor 647 over the traced circuit including the receiver of telephone L6 to conductor 648, condenser 652, to conductor 113.

Assume that the called party at telephoneL6 restores the receiver at the termination of the conversation, the calling subscriber still holding the receiver 011' the switchhook. Relay 646 will deactuate, restoring the direction of current traversing the receiver oi. telephone L to that primarily existing. Upon the calling subscriber now replacing the receiver on the switchhook opening the energizing circuit of relay 601, and its dependent relay 606, a circuit can be traced from the winding of release-magnet Re6, armature 655, spring 656 to grounded armature 608, the release magnet operating to restore the shaft .-carrying wipers 616 to 619 to normal position.

Ground being removed from conductor 609 consequent to armature 608 retracting, lineswitch LS, first selector FS and second selector "SS will 11 restore in the well known manner, whereupon the concerned circuits and. equipments are at normal.

It, at the time wiper 617 engaged bank contact 626 it found ground potential thereon, due to a connector having access ,to a multipled contact 134 thereof being in seized engagement with it, ap-- plying a ground to it as was set forth in relation to connector F hereinbefore, a circuit would ,have been established from grounded contact 626, wiper 617, wiper 622, winding of relay 657, make- 13 before-break spring 621 to the winding of private magnet P6, thus maintaining the private magnet, notwithstanding the retraction of armature 620. Under this condition sideswitch wipers 615 and 622 are not permitted to advance into their third position, so that relay 629 will not actuate. Consequent to the actuation of relay 657, grounded tone source T6 is applied through-armature 659 to conductor 648 and over the described path including the receiver of telephone L, conductor 603, upper winding of relay 601 to grounded battery, the tone being audible to the calling subscriber indicative that the line leading to telephone L6 is busy. A locking circuit for relay 657 is established incidental to its actuation from the winding of private magnet P6, spring 621, winding of ,relay 657, armature 660, armature 661, conductor 644, to grounded spring 645. The tone, and the private magnet is thus maintained until the locking circuit is opened at spring 645, which no can only occur when the switch has been restored to normal by the calling subscriber replacing the receiver on the switchhook, as described.

Inasmuch as features of novelty in connector F residein the converting relay 662 and in bank contact 625, wiper 616, and the circuits interlinked therewith, and that these have not been brought into requisition in the described call from telephone L to telephone L6, the functioning of the equipments concerned has been substantially as in well known types of equipments. However, it will appear presently, the connector F operates in a novel manner under certain operativeconditions which relate to calls efiected wherein a toll selector B cooperates with it, in lieu of a local selector SS as has been described.

With reference to Fig. 15 it will now be seen how a call is extended through the toll switchboard springjack D to called telephone L6. Upon inserting switching plug 501 of switching cordpair G into springjack D leading over a trunk to toll first selector E, spring 502 applies its ground to conductor 503. In this connection it will be stated that conductors 503 to 506 are in multiple relation to other springjacks similar to D and that there are lamps connected correspondingly to 507 associated with each said springjack so that when the multipled lamps corresponding to 507 glow due to conductor 503 becoming grounded operators will know that the first selector E is busy by having been seized by some operator having access to it. A circuit can now be traced from the winding of marginal relay 508, makebefore-break spring 509 of calling device key d, sleeve conductor 510, conductor 512, spring 513, conductor 504, armature 514 to the winding of relay 515, relay 515 actuating. A circuit can now be traced from grounded armature 516 to the winding of slow releasing relay 517, relay 517 actuating. .Grounded armature 518 places a supplemental ground on conductor 503.

The operator will now manipulate calling device key d, whereupon a circuit can be traced from ground through the calling device 520 (which is similar to the calling device in tele= phone L), spring 521, spring 509, conductor 510, conductor 512, spring 513, armature 514 to the winding of relay 515. Upon the operator manipulating the calling device 520 in accordance with the first digit 1, relay 515 will de-actuate and reactuate one time responsive thereto, whereupon armature 516 closes a circuit from its ground, armature 523, series winding of slow-releasing relay 524, armature 525 to the winding of the vertical magnet V5, the vertical magnet operating one time resultant thereto and raises theshaft carrying wipers 526 to 529 one vertical step into alignment with its first bank level.

At the time relay 524 actuates, coincident with the energization of the vertical magnet V5, its armature 533 applies ground from conductor 503 to make-before-break spring 534, winding of relay 535, armature 536, on the rotary magnet R5 to grounded battery, relay 535 actuating and closes a locking circuit from its upper winding terminal, spring 537 of off-normal set 0N5, conductor 538, armature 539, to grounded conductor 503. Oil-normal set 0N5 operates upon the first ofi-normal movement of the shaft. Upon the retraction of armature 533 a circuit can be traced from the winding of rotary magnet R5, spring 534, spring 537, conductor 538, armature 539 to grounded conductor 503, the rotary magnet operating and advances wipers 526 to 529 into engagement with bank contacts 541 to 54% respectively acumen and incidentally disconnects the battery energizing relay 535 at armature 536, relay 535 deactu ating. armature 536 retracts after the described energizing circuit of the rotary magnet is opened at armature 539 a circuit can be traced from grounded battery armature 536, winding of relay 535, spring 537, conductor 538, winding of relay 546 to grounded conductor 503, relay 546 actuating. The marginal adjustment of relay 535 is such that it will not operatively energize with the winding of relay 546 included with its winding. Relay 546 being actuated, the winding of relay 515 is disassociated and it retracts, followed by the de-actuation of relay 517 in sequence.

A circuit can now be traced from conductor 504, armature 514, wiper 527, bank contact 542, conductor 400, armature 401 to thewinding of relay 402, relay 402 actuating. Upon relay 402 actuating, a circuit can be traced from the winding of slow-releasing relay 403 to grounded armature 404, relay 403 actuating. Armature 405 engages grounded contact 406 and grounds conductor 407 which is communicated to bank contact 541, wiper 526, armature 550 to conductor 503, supplementing the ground thereon received from the spring 502. The telephonic circuit extends from the tip spring 551 of spring-jack D, conductor 505, armature 552, wiper 529, bank contact 544, conductor 553 to winding 408 of repeating coil 1', and from the ring spring 554, conductor 506, armature 555, wiper 528, bank contact 543,

conductor 556 to winding 409 of repeating coil 1'.

Having in mind that the bank contacts in cooperative relation with selector E are in multiple relation with corresponding bank contacts in cooperative relation with other selectors belonging to the group containing E, and the-fact that when armature 550 attracts it applies ground from conductor 503 to wiper 526 and to bank contact 541 and its multiples that had the selector B been in a seized condition before the described operation ensued relating to switch E in seizing it, bank contact 541 would have constituted ground potential. Therefore, when wiper 526 encountered bank contact 541 and received ground potential therefrom, it would have applied it to the lower winding terminal of relay 546 in common with the ground received from conductor 503 by way of armature 539. Relay 546 having ground on both of its winding terminals cannot be energized, so when armature 536 retracts following the driving of wipers 526 to 529 into engagement with bank contacts 541 to 544 respectively, an

energizing circuit operative to relay 535 will be established from grounded battery, armature 536, winding of relay 535, spring 537 to grounded conductor 538. Armature 539 will again lock the winding of relay 535 to grounded conductor 503 and the rotary magnet R5 will be operatively reenergized over the before described path to conductor 503 and an auxiliary path from conductor- 538, armature 550, wiper 526 to grounded bank contact 541 which will cause the rotary magnet to advance the wipers 526 to 529 an additional step into engagement with bank contacts 558 to 561 respectively, the re-actuation of relay 535 and the re-functioning of the rotary magnet occurring to advance the wipers successive rotary steps as long as wiper 526 receives ground to re establish the energizing circuit of relay 535 following its de-energization incidental to the rotary magnet operating.

Continuing from the seizure of selector B by selector E as set forth, upon the operator sending Armature 539 being now retracted, when I the second digit 2" relay 402 will de-actuate and re-actuate two times responsive thereto, whereupon armature 412 closes a circuit from its ground, armature 413, armature 414, winding of series slow-releasing relay 415 to the winding of the vertical magnet, V4, the vertical magnet operating two times resultant thereto and raises the shaft carrying wipers 416 to 419, 479 and 483 two vertical steps in alignment with its second bank level. At the time relay 415 actuates,'coincident with the energization of the vertical magnet V4, its armature 420 applies ground from conductor 407 to conductor 421, spring 422 of off-normal set 0N4 to the shunted winding of relay 425, relay 425 actuating. Off-normal set 0N4 operates upon the first elf-normal movement of the shaft. A locking circuit for relay 425 is established from grounded armature 426, armature 427 on rotary magnet R4, conductor 421, spring 422, to the winding of relay 425. Upon the retraction of armature 420 a circuit can be traced from the winding of the rotary magnet R4, armature 428, armature 420 to grounded conductor 407, the rotary magnet operating and advances wipers 416 to 419, 4'79 and 483 into engagemen'; with bank contacts 430 to 433, 493 and 494, respectively. Upon armature 427 retracting a circuit can be traced from the winding of relay 425, spring 422, conductor 421, armature 427, conduclor 445, winding of relay 446 to grounded conductor 407, relay 446 actuating. Relay 425 is marginally adjusted to not operatively energize over a circuit including the winding of relay 446.

Had wiper 418 encountered ground potential on bank contact 432, ground poiential received therefrom would be conducted over wiper 418, armature 447,conductor 450,armature 451 to conductor 445, thus maintaining ground potential on both winding terminals of relay 446, and a ground path from the winding of relay 425, spring 422, conductor 421, armature 427 to the ground on conductor 445, operatively energizing relay 425, whereupon the rotary magnet R4 will be caused to operate as before and advance the wipers an additional rotary step; this functioning continuing until wiper 418 fails to receive ground potential from an engaged bank contact.

Having in mind that the bank contacts in cooperative relation with selector B are in multiple relation with corresponding bank contacts in co-operative relation with other selectors belonging to the group containing selector B, it will presently appear that the assumed ground on bank contact 432 would occur whenever a selector belonging to the group containing selector B is in seized relation to its co-operative set of bank contacts.

consequent to the actuation of relay 446 set forth a circuit is established from grounded armature 412, armature 453, conductor 454, wiper 416, bank contact 430, conductor 455, makebefore-break spring 602 to the upper winding of relay 601, no circuit being traceable from the lower winding of relay 601. However, relay'601 is operatively energized over the traced path. Upon the actuation of relay 601 the hereinbefore described actuation of relay 606 ensues, applying ground from armature 608 to conductor 609. A circuit can also be traced from grounded battery, resistance 456, armature 451, conductor 450, armature 447, wiper 418, bank contact 432, conductor 457, winding of relay 662 to grounded conductor 609, relay 662 actuating. At this juncture relay 546 in selector E, relays 446, 402 and 403 of selector B and relays 601, 606 and 662 of connector F are actuated.

Upon the operator sending the third digit 1, I

relay 601 will be caused to de-actuate and reactuate one time and cause the connector F to function as hereinbefore described to step itsv wipers 616 to 619 into alignment with its first bank level. Upon the operator sending the fourth digit 2, relay 601 will be caused to deactuate and re-actuate two times and cause the connector F to function as hereinbefore described and to step its wipers 616 to'619 into engagement with bank contacts 625 to 628-respectively.

It is assumed that the subscriber upon whose premises telephone L6 is located also 'has a manual toll loop, such as is shown in Fig. 10, extending from a springjack M on the exchange toll switch-board to an independent telephone T10 on the premises of the said subscriber. It will be further assumed that the toll operator inadvertently or unknowingly called the subscriber's said local number to complete the toll call in place of properly routing it over the said toll loop. Upon the wipers 616 to 619 engaging bank contacts 625 to 628 respectively grounded special tone source S6 will be applied from bank contact 625, wiper 616, armature 665, conductor 666, bank contact 431, wiper 417, armature 460, winding 409 of repeating coil 1', conductor 556, over the described path to spring 554 of springjackD, conductor 565 of plug 501, spring 566 of key e, spring 567 of listening key 9 (now operated) through operator circuit N5, spring 568, spring 569, conductor 570, spring 551 over the described path to winding 408- of the repeating coil 1', armature 463, resistance 464 to ground, the said tone being audible to the calling toll operator, and due to its distinctiveness, is indicative that the subscriber called has a manual toll loop as set forth. In this connection, it will be observed that due to the fact that relay 662 is attracted incidental to the connector F being seized by selector B, that the before traced path from grounded ringing current source G6 is open at armature 632, and therefore, under the condition of the connector F being seized by toll selector B the automatic application of ringing current to a seized subscriber's line will not ensue. Under the condition of receiving the stated tone the toll operator may withdraw the plug 501 preparatory to inserting it into springjack M and thereafter depressing the ringing key e and apply the ringing current source G5 in bridge of springs 52 and 53 of springjack M leading to telephone T10 and operate the bridged signal device 54 thereat.

Assuming first that the operator withdraws the plug as referred to in the foregoing paragraph, ground on spring 502 will be removed from conductor 503, however, to no operative result because of conductor 503 receiving the stated supplemental ground by way of armature 405 in selector B. However, spring 513 will open the traced energizing circuit of relay 402, causing it to deactuate and, in turn, open the traced energizing circuit of relay 601, causing it to deactuate. The retraction of relay 601 will cause the connector F to be released as hereinbefore described with relation to the call from telephone L to telephone L6. The retraction of relay 402 followed by relay 403 in sequence, will establish an operative circuit from grounded armature 412, armature 413,

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armature 414, spring 465 to the release magnet the traced energizing circuit for relay 546 will be opened, whereupon relay 546 will de-actuate, establishing an operative circuit from grounded armature 516, armature 523, winding of relay 524, armature 525, spring 575 to the winding of release magnet Re5, causing selector E to restore its shaft to normal position, whereupon the concerned circuits and equipments are at normal.

Assume now that for some reason,perhaps that the manual toll loop extending to the premises of the called subscriber is busy and the toll operator, therefore, wishes to complete the connection over the seized local line to telephone L6 in lieu of releasing the connection. The line having been seized, but not rung upon, the operator will depress ringing key e and apply ringing current source G5 in bridge of the traced circuit leading to the lower winding 408 and the upper winding 409 of repeating coil 1'. The inner terminals of the windings 408 and 409 are open at armature 460, but the relay 466 including condenser 467 is included in a bridged circuit from the outer terminal of the winding 409 by way of armature 468 to the outer terminal of winding 408, therefore, in a bridge of conductors 556 and 553. Relay 466 is operative to the impressed ringing current from source G5 and attracts its armature 470 into engagement with its co-operating grounded contact, applying the ground to the winding of slowreleasing relay 471, causing it to actuate. Armature 447 attracting (after armature 472 attracts), opens the traced energizing circuit of relay 662, whereupon said 662 deactuates. Armature 472 attracting into engagement with its co-operating grounded contact applies ground through wiper 419, bank contact 443, conductor 473 to the winding of relay 675, causing it to actuate. A circuit can now be traced from grounded ringing current source GT6, armature 631, armature 632, armature 633, armature 634, wiper 619, bank contact 628, condenser 642, signal bell 641, bank contact 627, wiper 618, armature 635, armature 636, armature 637, armature 638, resistance 676 to grounded battery, the signal bell 641 operating. Upon the operator restoring the key e relay 466 will retract, opening the traced energizing circuit of relay 471, causing relay 662 to re-actuate, followed by relay 675' de-actuating in correspondence with the stated relative adjustments of armatures 447 and 472.

Upon the called subscriber responding, by removing the receiver of telephone L6, a circuit can be traced from the upper winding of relay 475, armature 476, winding 477 of repeating coil 1', conductor 478, wiper 479, bank contact 480, conductor 481, armature 637, armature 636, armature 635, wiper 618, bank contact 627, receiver of telephone L6, bank contact 628, wiper 619, armature 634, ,armature 633, armature 632, conductor 678, bank contact 482, wiper 483, conductor 484, winding 485 of repeating coil 1', armature 486, to the lower winding of relay 475, relay 475 actuating. consequent to relay 475 actuating the traced path including relay 466 is opened. Relay 402 is dis-associated and armature 488 applies ground from its co-operating grounded contact through armature 453, conductor 454, wiper 416, bank contact 430, conductor 455, spring 602 to the upper winding of relay 601, maintaining relay 601 actuated. Armature 401 is applied to its working contact and, therefore, applies conductor 400 to the winding of relay 403 in lieu of to the winding of relay 402 normally existing. The winding of relay 402 has such a resistance as will permit current sufficient to operatively energize the includ ed winding'of relay 508 to flow, and, therefore,

de-energizing relay 475, the primary circuit relations will re-exist and relay 508 will be again operatively energized in series with the winding of relay 402, whereupon lamp 570 will re-glow as a clearing signal.

The telephonic circuit previously traced to the inside terminals of the windings 408 and 409 of repeating coil r is closed through armature 460. The telephonic circuit traced through the called telephone to the inner terminals of windings 477 and 485 of repeating coil 1'; the said inner terminals being connected by condenser 489, and in view of the windings 409 and408 being in inductive. relation to companion windings 477 and 485 respectively, the toll operator, through the operator circuit N5, is in telephonic relation with the called subscriber through the receiver of telephone L6. It is manifest that upon the armatures 460 and 463 attracting, the special tone derived from tone source S6 is disassociated from the telephonic conductors.

Assume that telephone L6 had been called by sending digits corresponding to telephone number 1211 wherein the last digit 1 will cause wipers 616 to 619 to engage bank contacts 681 to 684 respectively and wherein the telephonic circuit traced to wipers 618 and 619 will include a path through the telephone L6 in a manner corresponding to the inclusion of telephone L6 when engaged with bank contacts 627 and 628 respectively. Wiper 617 will apply ground. to the winding of cut-off relay 685 through bank con- The tone projected from tone source U6 differs j from that projected from tone source $6, the

tones being distinctive so as to prompt the toll operator of specific conditions with reference to the respective subscribers L6 and L6. For example, in the case of tone source U6 it may be 3 indicative that the subscriber is not to be accorded credit, and therefore, no collect toll message shall be completed. It would be equally practicable to have the tone from the source U6 indicative that the subscriber can be reached j through an independent toll automatic exchange over an automatic toll loop, or in fact any of many special facts relative to the subscriber. -It is manifest that there may be a greater plurality than the two tone sources (S6 and U6) available for interchangeable connection to bank contacts.

engageable to wiper 616, each indicative of a specific condition or conditions relative to the subscriber.

Assume that at the time the wipers 616 to 619 inbefore set forth, that the line leading to tele- 1' phone L6 is busy. A circuit can be traced as before from grounded contact 626, wiper 617, sideswitch wiper 622, winding of relay 657, spring 621 to the winding of the private magnet P6, relay 657 actuating, and it and the private magnet being maintained after the retraction of armature 620. Tone source T6 is applied through armature 659, resistance 685', conductor 6'78, bank contact 482, wiper 483, conductor 484, winding 485 of repeating coil 1', armature 486 to the lower winding of relay 475. The tone will be induced into winding 408 audible to the toll operator calling, indicative that the called line is busy. Due to armature 661 being attracted, the locking circuit hereinbefore traced to the winding of relay 657 will not be completed, and therefore, the attraction of relay 657 will only endure as long as wiper 617 receives ground from bank contact 626; that is to say, until the line leading to the telephone L6 becomes disengaged. Under this condition, the operator can hold the connection awaiting the disengagement of the called line, whereupon the connector F will seize as before described, due to the fact that when the ground is removed from bank contact 626 the private magnet P6 is deenergized, permitting the sideswitch wipers 615 and 622 to advance into their third position, energizing relay 629 and applying busy ground to bank contact 626 and its multiples.

It is manifest that upon receiving the busy tone last assumed that two independent tones will be audible to the calling toll operator. One tone being that derived from tone source S6 and the other being that derived from busy tone source T6. In order for these tones not to be confusing, they are not applied constantly and are so timed in their propagation and duration that they are alternately audible. This expedient is attained through timing the interrupter control segments as by giving them suitable angular position with respect to each other on the shaft driving them. The same method of alternatively applying tone sources which may be successively applied audible to the calling toll operator to index a plurality of specific conditions relative to a subscriber is contemplated under the present invention. For example, the tone applied to a bank contact engageable to wiper 616 may constitute a cycle of tones consisting of a plurality of specific tones, each indicative of a special condition, as that the subscriber called has an automatic toll loop, a manual toll loop, that collect calls are to be completed only upon the subscriber personally recognizing the charge, that if no response is obtained instructions are on file which the operator shall consult as to where the call can be completed,

etc.

In view of the foregoing, with relation to the application of tones, it will be understood that the various tone sources of the exchange are so .timed and durated that tone sources which may be successively applied will not be operative during the same period, that is, there will be audible and silent periods for the various tones and the said periods intermesh when considered in plurality. It will thus be clearly understood that the toll operator may receive a composite tone, possibly applied from a single composite tone source of predetermined character, which will indicate a plurality of facts relative to the subscriber called.

In carrying out the present invention in commercial exchange systems it is not always practicable to install a manual toll loop from the premises of the subscribers to the exchange toll switchboard, nor would independent automatic toll switching equipments be installed to which automatic toll loops could'be connected. This is having in mind that the subscribers lines lead into various main branch oflices of the exchange, all of which may be remote from the exchange toll switchboard, or from the terminating first selector (corresponding to E) of a toll line equipped for automatic calling.

It is manifest that it is practicable to reserve certain numbers in each hundred-group bank accessible to the connectors, as F, to which exchange toll loops can terminate in a manner corresponding to L6 or L6. That is, for example, the telephone line leading to telephone T23, may have its telephonic conductors and private normal conductor related to bank terminals accessible to connector F corresponding to the relation of the telephonic conductors and the private normal conductor of the line leading to telephone T6. So, in view of the descriptions relating to the equipments of the line extending to telephone T23 which will be detailed presently, it will be clear that exchange toll loops may be terminated in the same hundred groups as the local exchange lines of the subscribers concerned- Having the exchange toll loops in the same hundred group is particularly advantageous in view of the novel release function of connector F under control of a toll operator when it is seized by a t )11 selector B, about to be described.

It will be assumed that upon the toll operator (exchange or remote) attaining the bank position containing bank terminals 681 to 684 corresponding to the line leading to telephone L6 atom is received indicative that the concerned subscriber has an exchange toll loop in the same bank group, and tone is received indicative of the calledline being busy. The toll operator will consult the toll loop directory and ascertain the bank position (corresponding to the last two digits of the telephone number) of the said exchange toll loop. That is-to say, the telephone number of the said loop.

In order to effect connection with the desired exchange toll loop the operator will send digit 1, whereupon relay 601 will de-actuate and reactuate one time responsive thereto. Upon armature 607 retracting it will apply its ground through armature 612, conductor 687, armature 688 on relay 657 which is actuated due to the -busy condition found, armature 689 on converting relay 662, to the winding of the release magnet Re6, the said release magnet actuating to restore the shaft of connector F to normal position, toll selector B retaining its seizure thereof. The toll operator can now send the last two digits of .the telephone number corresponding to the exchange toll loop extending to telephone T23 and cause the connector F to attain its bank position, whereupon it will seize its contacts if the said loop is idle, or apply a tone audible to the calling operator indicative thereof if it is busy, in the manner hereinbefore set forth when the line leading to telephone L6 was assumed busy.

Assume that the line leading to telephone L6 does not test busy when wipers 616 to 619 attain engagement with bank contact 681 to 684 respectively, and therefore relay 657 will not actuate, but that cut-on relay 629 will actuate to effect a seizure, instead. The calling operator discerning the tone indicative of the fact that the called subscriber has an exchange toll loop in the same bank group will refrain from applying signaling 159 current. Upon sending digit "1", whereupon relay 601 will de-actuate and re-actuate one time and armature 607 will apply its ground through armature 612, conductor 687, armature 613, (in lieu of 688 in the before traced path) armature 689 to the of the release magnet Red, the said release magnet actuating to restore the shaft of connector F to normal position, the toll selector B retahzing its seizure thereof. The toll operator can now send the last two digits of the telephone number corresponding to the exchange toll loop extending to telephone T23 and cause wipers of the connector F to attain its bank position, whereupon it will function in accordance with its busy or idle condition as set forth hereinbefore.

It is thus manifest that if the connector F attains a bank position, controlled by a toll operator through a toll selector B, and it there encounters either a busy line from which it is barred, or an idle line which it seizes, dialing digit 1 will restore the connector and maintain the interlinked circuits up to and including the said connector, preparatory to operating the connector as primarily.

It is clear that wipers 616 and 617 may be tied, and the engageable pairs of bank contacts thereof may be tied, without operative change. That is to say, the conductor leading to wiper 616 may be changed to wiper 617 and the tone connections to bank contacts 681 and 625 may be changed to bank contacts 682 and 626 respectively.

With reference to Figs. 8, 12, and 16, and also with reference toparagraphs, a, b, c, d, e, f, g, h, i and 7', the'operation of connector A under various assumed operative conditions will be discussed.

In order not to unduly complicate the drawings, only a portion of the connections are shown relating to the bank contacts co-operating with connector A. Bank J shown in Fig. 8 is a somewhat more complete representation of the bank co-operating with the connector A and it shows one of the multiplied banks K co-operating with a connector of the group containing connector A. Only the first and second bank levels are shown, and only six sets of contacts are shown for each level. In commercial systems the bank would consist, ordinarily, of ten levels of ten sets of bank contacts each and would, therefore normally refer to a hundred lines or a hundred bank positions. Usually ten or more banks are connected in a set with their contacts connected in multiple relation respectively, so that the cooperating connectors each have access to the same leading-out lines at corresponding bank positions.

The connector A is a combination local and toll group-selecting connector which is normally not a group selecting-connector. The group-selecting function depends upon a set-up condition being introduced, depending upon the condition found by one of its wipers when it engages the co-operating bank contact of the bank position called. It will appear presently that the connector A functions differently depending upon whether it is seized by a local selector or by a toll selector.

The exampled operative condition which will be assumed in relation to connector A contemplates varied classes of service. For example, referring to Fig. 16, bank position 11 is dead. Bank position 12 refers to an isolated local subscriber's exchange line. Bank positions 13, 14, 15 and 16 refer to a group of three lines relating to a single subscriber, and moreover, the subscriber has an independent manual, (or automatic) toil loop. Bank positions 21 and 22 refer to a group of two local subscriber's line positions relating to an isolated subscriber's line. Bank positions 23 and 24 refer to a group of lines relating to a single subscriber, and moreover, the first line of the group occupying bank position 23 is an exchange toll loop. Bank positions 25 and 26 refer to a group of two local subscribers line positions relating to an isolated subscriber's line.

It will appear, presently, that if a local subscriber (calling through a localiselector) causes the wipers of connector A to attain bank position 12 the connector will'function as a nongroup-selecting connector. That is, will seize the line thereof and automatically apply ringing current to it, if it is not busy, and if it is busy will apply a tone audible to the calling subscriber, indicative of the condition. If a local subscriber causes the wipers of connector A to attain bank position 13 it will automatically rotate-off as a group-selecting connector, regardless of its busy or idle state, its wipers attaining bank position 14, where it will seize the line thereof, if it is not busy, and if it is busy, it will automatically rotate-ofi as a group selecting connector, its wipers attaining bank position 15, where it will seize the line thereof if it is not busy, and if it is busy, it will automaticallyrotate-oif as a group-selecting connector, its wipers attaining bank position 16, where it will seize the line thereof if it is not busy, and if it is busy, it will apply a. tone audible to the calling subscriber, indicative of the condition. If a local subscriber causes the wipers of connector A to attain bank position 21, it will automatically rotate-01f as a group-selecting connector, regardless of its busy or idle state, its wipers attaining bank position 22, where is will seize the line thereof if it is not busy, and if it is busy, will apply a busy tone audible to the calling subscriber, indicative of the condition. If a local subscriber causes the wipers of connector A to attain bank position 23, it will auto.- matically rotate-off as a group-selecting connector,'regardless of its busy or idle state, its wipers attaining bank position 24, where it will seize the line thereof if it is not busy, and if it is busy, will apply a busy tone audible to the calling '125 subscriber, indicative of the condition. If a local subscriber causes the wipers of connector A to attain bank position 25 it will automatically rotate-ofi as a group-selecting connector, regardless of its busy or idle state, its wipers attaining bank position 26, where it will seize the line thereof, if it is not busy, and if it is busy, will apply a busy tone audible to the calling subscriber indicative of the condition.

Assume that it is desired to reach the local line leading from the bank contacts occupying bank position 15, this line leading to a specific telephone on the premises of the subscriber or is temporarily connected to such a telephone, perhaps at night or on a holiday. Upon the calling subscriber, calling through a local selector, causing the wipers of connector A to attain bank position 15 it will seize and ring upon the line thereof if it is idle, and if it is busy, will apply a tone audible to the calling subscriber indicative of the condition. This is to say, if the line is busy it will not function as a group-selecting connector and rotate its'wipers into position 16.- Thus, where the wipers of the connector A primarily attain an interme diate bankposition of a group it will not thereafter function as a group selecting connector when controlled through a local selector. However, it will presently appear that where the connector is controlled through a toll selector, the toll operator by sending digit 1 can cause it to thereupon function as a group-selecting connector. Therefore, upon the operative condition referred to with respect to calling through local selectors, it will appear that if the specific intermediate line called is busy an alternative line will not be seized, though under the operative condition of operating the connector A, controlled through a toll selector, the operation of the said connector by way of hunting for an alternative line of the group if an intermediate line is called is optional, at the will of the toll operator.

It will appear, presently, that if a toll operator exchange or remote, calling through a toll selector causes the wipers of connector A to attain bank position 12, the connector A will function as a non-group selecting connector. That is, it will seize the line thereof preparatory to the toll operator causing ringing current to be applied to it at will, if it is not busy, and if it is busy, will apply a tone audible to the calling operator indicative of the condition. If a toll operator causes the wipers of connector A to attain bank position 13, it will seize the line thereof, preparatory to the toll operator causing ringing current to be applied to it at will, if it is not busy, and if it is busy, will apply a tone audible to the calling operator indicative of the condition. Under either condition, that of finding the line occupying the bank position 13 (also appearing in bank position 14) idle or busy, a tone will be applied audible to the calling toll operator that is of such'specific nature that it is indicative that the called subscriber has a toll loop which may be manual or automatic, depending on the significance of the tone. line occupying bank position 13 is busy, a composite tone will be audible to the calling toll operator indicative of the said two conditions, the general nature of the composite tone being as hereinbefore referred to. The calling toll operator at this juncture can either withdraw the switching plug and release the connection in the manner as will appear presently and complete the call to the called subscriber over his independent toll loop, or the operator can apply ringing current at will to the selected line after it becomes idle and the connector thereupon automatically seizes in the manner as will appear presently. In this connection it will be remembered that the line seized at bank position 13 is the same line as appears in bank position 14, therefore, if a busy condition is'found at bank position 13 as set forth, a busy condition will also exist on the line should it have been seized through bank position 14.

Assume now that when the toll operator causes the wipers of connector A to attain bank position 13, the busy condition alluded to is found. And further, it will be assumed that the toll operator desires to complete the call over one of the subscribers local lines. In order to initiate the group-selecting operation of connector A the calling toll operator will send digit 1, whereupon the wipers of connector A will be advanced to bank position 14, and due to the busy condition that will also be found there, will automatically advance the wipers intobank position 15. If the line leading from bank posi If the tion 15 is idle the connector will seize, preparatory to the toll operator applying ringing current over it at will, and if the line thereof is busy the wipers will be automatically advanced to bank position 16, where the connector A will seize if the line thereof is idle, preparatory to the toll operator applying current'to it at will, or if it is busy, to apply a tone audible to the toll operator indicative of the condition.

If the line occupying bank position 1615 busy as assumed in the foregoing paragraph, the operator can release the shaft of connector A to normal position by sending digit 1. If the connector A is released in the manner provided, the calling toll operator by sending the last two digits of the called number, can cause it to function as before, or by sending two digits relating to some other bank position, can cause it to be operated by way'of reaching the line leading to the premises of some other wanted subscriber also accessible to connector A. This feature is particularly advantageous in that it obviates releasing the entire connection if a busy line condition is encountered. Where the call emanates from a remote toll switchboard it admits of the line and connections up to and including the connector being retained interlinked when releasing the connector, and thus saves the time of operators and toll lines that would necessarily have to be occupied in establishing a new connection up to the connector, were it necessary to release the entire connection.

If the toll operator desires to reach a specific line of the group 13-14P15-16, the line leading from the bank contacts occupying bank position 15 for example, and accordingly sends the proper impulses to cause the wipers of connector A to primarily attain that bank position. If the line is idle, the connector will seize, preparatory to the toll operator applying ringing current to it at will, and if it is busy a tone audible to the toll operator will be applied indicative of the condition. Under this condition, that of primarily attaining an intermediate bank position of a group, the connector will not be automatically adapted to function as a group selecting connector. However, upon the operator sending digit 1 following the connector primarily attaining the called bank position the connector will thereupon function as a group-selecting connector and seek the first succeeding idle line. This functioning will not depend upon the bank position primarily attained being busy. That is to say, if the operator after ringing upon an idle line fails to get a response, sending digit 1 will cause the connector to advance its wipers to the first idle line of the group and seize it preparatory to the calling toll operator applying ringing current at will. Of course, if the last line of the group is seized or found busy, the connector will not rotate beyond the group containing the called line thereof by reason of the toll operator sending digit 1 but will, under such condition, restore the shaft to normal position as has been adverted to hereinbefore.

It will also appear, presently, that if a toll operator (calling through a toll selector) causes wipers of connector A to attain bank position 21, said connector A will automatically function as a group-selecting connector and rotate its wipers into bank position 22. In this connection it may be stated that neither a local subscriber nor a toll operator can cause connector A to stop its wipers resting upon the bank contacts of bank position 21, for reasons as will appear presently. If the

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