US1259496A - Telephone-call-distributing system. - Google Patents

Description

A.H.,DYSON TELEPHONE CALL DISTRIBUTING SYSTEM.

APPLIQATION FILED JAN. 30. I9I3- RENEWED JAN. 22. I916.

Patented Mar. 19

SHEETS-SHEET I.

A. H. DYSON.

HELEPHOIIIE CALL DISTRIBUTING SYSTEM. APPLICATION- FILED 1AN.30, 1913. RENEWED JAN. 22. I916- 159A96u Patented; Mar. 19, 19m.

4 SHEETS-SHEET 2.

Z/ 2772795555: fizz/522232":

farm/557 v A. H. DYSON.

TELEPHONE CALL DISTRIBUTING SYSTEM. APPLICATION FILED JAN. 30, 1913. RENEWED JAN. 22'. 1916.

1,259,496. Patented. Mar. 19,1918.

asngfls snin 3. WW:- i m s 19 i b A. H. DYSON. TELEPHONE CALL DISTRIBUTING SYSTEM. APPLICATION FILED JAN. 30. 19:3. RENEWED JAN. 22. 1916.

Patented Mar. 19, 1918.

In K3 fin/527E721 4 HEETS-SIEET 4. Y. L.

ALFRED H. DYSON, OF NEW .YOBK, N. Y., ASSIGNOR T0 KELLOGG SWITCHBOARD AND SUPPLY COMPANY. OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

TELEPHONE-OALL-DISTBIBUTING SYSTEM.

Specification of Letters Patent.

Patented Mar. 19, 1918.

I hpplication'fllcd January 80, 1913, Serial No. 745,069. Renewed January 22, 1916. Serial No. 78,761.

To all whom it ma concern:

Be it known tiiat I, ALFRED H. DYSON, a citizen of the United States of America, residing in New York city, county of New York, and State of New York, have invented certain new and useful Improvements in Telephone Call Distributing Systems, of which the following is a specification.

My invention relates to telephone systems in general, certain features thereof being directed more particularly to telephone call distributing systems, an object being to provide a system as named which is readily applicable to operating exchanges of a wellknown so-called three-wire type.

Where it is desired to change over an operating manual telephone system to a call distributing system 1t is apparent that it is a desirable feature to be able to change over the existing system at the lowest expense and at the same time secure a simple, positive and efficiently operative system, and to this end I have worked out my invention, several forms of which are shown in the accompanying drawings. The new features of my lnvention will be more definitely pointed out in the ensuing specification and claims.

Figure 1 comprising parts 1 and 2 illustrates one form of my invention.

Fig. 2 illustrates diagrammatically a contact bank and wiper arrangement of a preferred form of switch construct1on used with my invention.

Fig. 3 comprising parts 1 and 2 illustrates another embodiment of my invention and Fig. 4 shows a cord circuit adapted for use with the system of Fig. 3.

Referring first to the system of Fig. 1 it comprises in general, substations A-connected by line conductors L to line circuits B which terminate in jacks at a central oflice switchboard in a well-known manner. hach operators position includes answering plug C connected to an associated call distributing or cord selector switch D. These selectors D are divided into groups, each group having its bank terminals-multiply connected and extending to calling cord circuits E which are also divided into groups and distributed among connecting operators positions before which multiple terminals of the lines of the exchange are positioned. At the right end of Fig. 1, part 2 I have illustrated what we will assume as a ters being used to indicate parts correspondmg to the calling substatlon and-associated apparatus.

In general the system of Fig. 1 operates as follows: Assuming a calling subscriber at A removes his receiver from its switch-hook to initiate a call, an associated line signal LS is operated before a distributin operator who inserts an answering plug 0 into an an swering jack of the calling line whereupon the associated distributing switch D automatically distributes the call to an idle connecting cord circuit E before a connecting operator. The connecting operator in response to a si al 11 displayed at the seized connecting circuit E, ascertains by means of an operators telephone circuit, not shown, the number of the Wanted substation. The connecting operator then inserts the plug F of said connecting cord circuit into a jack of the wanted line-and then applies ringing current to the terminals thereof.

After the subscribers have finished conversation they replace their receivers upon their respective switch-hooks whereby a disconnect signal is received at the cord circuit E and the connecting operator thereupon Withdraws the connecting plug F from the jack of the called line, causing the display of a disconnect signal DS at the plug C whereupon the distributing operator withdraws the associated plug C from the jack of the calling line.

, Before proceeding with a more detailed description of Fig. 1, I will refer to the selector mechanism of the distributing switch D, preferably employed.

For use with the selector and connector circuits of the system of Figs. 1 and 2, a switch such as is shown in an application of William Kaisling for automatic switch for telephone systems, Serial No. 600,664, Patent No. 1,131,140 filed'January 3rd, 1911, may be used.

The switch referred to in the previous paragraph, in general comprises a bank of contact made up of 100 sets of contacts with three contacts 5, 6, 7, to each set, and divided into ten groups of ten contact sets each as illustrated diagrammatically in Fig. 2. A set of wipers T, P, S, are provided, to cooperate with the bank contacts, a primary magnet (corresponding to PM of the switch circuits) being adapted to primarily adjust,

the wipers through the medium of a primary shaft PS to select a group ofcontacts, and a secondary magnet corresponding to SM of the switchcircuits is provide .-to step the wipers throu h t emedium of a secondary shaft SS in a secondary direction in a plane at right angles to the primary, to select a contact set of the selected group.

' The switch construction is such that the I Wiper wiper are advanced against the tension of a pair of so-called watc opposing each movement respectively.

For each row or group of contacts 5, 6, 7

a grou them to control, the secondary magnet is. again actuated to step the wipers in a sec-1 ondary direction beyond the last contact of the group whereby they are automatically restored to normal by the springs referred to, but over a different path than thattaken by the wipersin the advance movement of the switch in selecting a contact, such a.

complete travel of the wipers being indicated .by the dotted line in Fig. 2. Thus, in

the operation of the switch the contacting ends of the wipers travel in a primary direction to select a group of contacts, then in a secondary direction to select a contact in the group, and in the release of the wipers this secondary travel is continued until the contacting ends have passed beyond the last .contact in the group, whereby they are automatically released to continue their restoration to normal, this continued movement being in a plane parallel to the primary movement but in an opposite direction until they I reach a point directly above the starting point when they are moved" downward through a plane parallel to the secondary movement, but in a direction opposite to the secondary movement, until they reach their normal starting point.

A set of primary off-normal spring contacts PON are moved upon the first primary step of the switchwhile a set of secondary ofl-normal spring contacts SON are moved upon the first secondary step of the switch.

If the primar adjustment of the switch is continued until the wipers have passed beyond the last contact/8 and row 5, 6, 7, a primary over-run switch POR is closed while ifthe secondary adjustment of the wipers T, P, S, is continued until they pass beyond a row, a secondary over-run switch SOB is closed, these over-run switches being restored in amanner as will be apparent springs, one spring frelay CO, answering and calling that for a more complete understanding of this switch, reference is to vbe had to the i from the drawing. It is to bei'unde'rstood comprises a substation A, the one illustrated .bein of'a well-known type, connected by a line comprising conductors 1 and 2 to a line circuit B at a central oflice. Said circuit B comprises a line relay LB, 9. cut-01f jacks J multiply connected tothe lin'e conductors 1', 2-, and a line signal LS.

A plurality of answering plugs C are provided at each distributing operators position, each one being connected by talking conductors 3, 4 ,to a distributing switch D.

A third conductor of plug C is connected to a starting relay STR which relay energizes upon inserting plug C, to start the selecting operation of the associated distributing switch D. p j

- As already outlined the distributing switch D has its bank terminals arranged in groups, and the wipers are adapted to be moved to select a group having an idle set of terminals and thereafter to such an idle set of terminals in the selected group. Each set ;of such terminals comprisesa testterminal '5, a' primary talking terminal 6 and a secondary talking terminal 7 there being preferably 10 such sets in each row as already outlined. For each such row of terminals a group terminal 8 is provided, andthere being 10 rows of terminals 5, 6, 7, there are of course 10 group terminals 8 and a cooperating group ,wiper GT; A test wiper T is provided for the terminals 5, and primary and secondary wipers P and S for the terminals 6 and 7 respectively. The primary adjustment of the wipers in selecting a group is efiected by a primary magnet PM, while the secondary adjustment of the wipers to select a contact of a group is eifected by a secondary magnet SM. A primary relay PR controls the primary adjustment bf the switch, while a secondary relay SR controls the secondary adjustment of the switch.

Each switch D also has a release relay RR, and a talking circuit closing relay CL, said relay CL being energized after an idle cord circuit E is selected.

The off-normal and over-run switches are indicated by reference characters which will be clearly understood from the switch description already 'ven. The over-run switches .in conjunction with the over-run relay ORR are adapted to automatically restore switch D to normal, should all of the cord circuits to which it has access be busy. For instance should all of the cord circuits be bu ya the a s swf ch D is started,

iao

new, i

the up wiper GT will of course step beyon the last group contact 8 and at this point switch POR is moved to its alternate position causing the energization of relay ORR and thereby effecting the restoration of the switch. Should some of the cord circuits to which a started switch D has access be idle, group ,wiper GT would of course stop upon selecting the first group containing such an idle cord, but should all of the cords in this selected group of contacts be rendered busy before the test wiper '1 reaches them, the secondary adjustment of the switch is continued until wipers T, P, S, are advanced beyond the last contact in the group whereupon'secondary over-run switch SOR is moved to its alternate position to effect the energization of ORR and the restoration of switch D. 1

As already outlined each row of switch contacts has preferably 10 sets of contacts 5, 6, 7 and there is a group contact 8 provided for each row. Therefore, means are provided to render a set of multiply connected group contacts 8 busy while the associated 10 cord circuits E are busy. To this end a group busy relay GB is provided for each cord circuit, said relay being energized as soon as its cord circuit is selected.

A series busy circuit 9 extends in series through normally open contacts 10 of each group of ten relays GB, the last relay GB? of the set having its contact as 10 connected to ground so that as long as the ten relays GB are energized this ground connection from alternate contact 10 is maintained connected to its associated group contacts 8. It will be apparent that as long as any one or more of a group of relays GB are deenergized, this series circuit will be interrupted so that the associated group contacts 8 remain selectable.

Referring now to cord circuit E, it comprises a repeating coil RC connected in cir-. cuit with the talking conductors ofthe cord circuit, and a calling plug F. An answering supervisory relay AS- is adapted to be energized upon selection of its cord circuit to light the calling signal 11. A calling supervisory relay CS is also provided which controls a supervisory signal 12. A shimt relay SH is energized upon inserting plug F in. a called line, to efiace signal lamp 11 while the ringing relay BI is adapted to apply ringing current to the terminals of the called line.

A ringing key N is provided for each cord circuit E said key being adapted to ring four party-line substations selectively or a single line-substation. Five ringing contact sets 0, M, K, H and-G are connected to generators 13, 14, 15, by connections extending through the interrupters 16, 17, and 18. Generator 13 is adapted to provide positive pulsations, generator 14 negative pulsations, and generator 15 a suitable alternating ringing current. The interrupters 16, 17 18, are constantly rotating and alternately connect the associated generator and batteryb-to the conductors 19, 20, 21. The ringing key N is so connected that when contacts 0 are operated, alternating current generator 15 is connected in bridge of the tip and ringacontacts of plug F. When contact sets are operated negative pulsations from generator 14 are connected to the tip of plug F. Contacts K are adapted for connecting positive pulsations from generator 13 to the tip of the plug, contacts H are adapted to connect positive pulsations from generator 13 to the ring of the plug and contacts G when operated connect negative pulsations from generator 14 to thering of the plug. The five sprin contacts are indicated by signs which rea ily show the current which is adapted to be connected and whether to the tip or sleeve side all of which will be apparent from the foregoing description. Key N is so arranged that when any of its plungers are actuated it will be held in its actuated position by clutch magnet CM until said magnet is deenergized. A ringing disconnect relay DR is connected in the ringing circuit and is adapted to be energized upon response of the called subscriber to eflect the energize.-

tion of clutch magnet control relay RR and thereby release clutch magnet CM and ringing relay RI.

In connection with called line L I have shown a substation A having a call bell is which is connected to the tip side of the line and adapted to be operated by positive pulsations when key K is pressed. In a like manner bells h, m, and g, are adapted to be operated when their corresponding keys H, M or G are depressed. It will be noted that like reference characters indicate the corresponding keys and substations.

Operation.

Having described in general the apparatus of Fig. 1, the operation of the system will now be described. Assumin the subscriber at substation A removes his receiver to initiate a call, a circuit for line relay LR is established over the calling line, thereby energizing said relay and lighting the line signal LS. The distributin operator before whom the answering j ac of substation A terminates, in response to said signal, in-

serts a plug G into the answering jack J of the calling line thereby connecting the talking contacts of plug -0 with the talkin contacts of jack J, while starting relay ST is connected through the third conductor in' series with cut-oil relay CO thereby energizing both relays STR and CO. Relay STR therefore closes its alternate contact 22 establishing a circuit for primary relay 3 PR traced from while wipers; T, P, S,

cup of bank contacts 5, 6, 7.

- Assuming justment of switch D.

. energization of P, S, into connection with alternate contact 25, estab lshin of contacts leads to a its test contact 5 w1ll\have aground or' ground atsaid' contact 22, normal contact-23 normal contact 24 and the win of 1 3 to battery.- Said relay PR there ore is ener ed closing its an 0 erating circuit for primary magnet I M. aid magnet therefore attracts its armature and causes a primary step'of the switch wipers whereby group-test wig-er GT is moved mto connection with the.

are moved opposite the first row or all 0 the cord circuits extending from this first group of bank contacts" are busy, all of their relays GBare energized and therefore the first group contact 8 has a gound or busy potential connected thereto as is indicated diagrammatically the drawing. Therefore, primary relay PR is maintainedenergized over a-circuittraced from said grounded contact 8, alternate contact 26, the winding of PR to battery. Therefore magnet PM causes another primary step of the switch and assuming the second group of bankcontacts are busy' a third primary step of the switch is effected. Assuming there is an idle cord circuit in this third group, there will be no busy potential upon its group contact8 and therefore relay PR deenergizes interrupting its alternate contact 25 and preventing any further primary ad- Thus it will be seen that switch D has automatically selected the first group of bank contacts havingan idle cord circuit.

The next step is to cord of this selected group this being brought about as follows. Upon said de- PR, its normal contact 25 closes establishing a circuit for secondary relay SR traced from-said ground at normal contact 25, alternate contact 27, normal contact 28, winding of SR to battery. Relay Slttherefore energizes closing its alternate contact 29 establishing an operating circuit for secondary magnet SM which attracts its armature and advances wipers T, the first set of contacts 5, 6, 7. Assuming this first set busy cord circuit,

busy potential connectedethereto, (due to its relay GB, contact 40 being closed) and therefore a locking circuit for SR is established from said grounded test contact 5, test wiper T, alternate contact 30, normal contact 31, the winding of SR to battery. It will be noted that upon. the first secondary ste rugted so that the initial circuit for SR is open. Relay SR remaining energized, magnet SM advances the wipers another secondary step and in fact continues to do so as long as test wiper T is engaging busy test contacts 5. Upon reaching the conducnoted that during this seco st group contact 8 SR to prevent the ground select the first idle of the switch SON contact 28 is inter-- assume is the first idle one. of the group,

there being no busy contact 5 the circuit'for SR is interrupted, deenergizing said relay to interrupt the circuit for SM and prevent any ondary adjustment of switc D.

dary travel of S has'its circontact 32 0f the switch, secondary wip r cult interrupted atmormal "tact 33 of RRinterfermg with anyexisting connections with which wiper'S may engage.

"SwitchD has now selected the first idle cord of the selected group andthe next step is to signal the operator at the selected connecting cord circuit E. Upon said deener gization of relay SR, a circuit for answering supervisory relay AS is established traced from ground at normal normal contact 32, conductor 34, normal contact 35, wiper S and contact 7, secondary conductor 36, the winding of AS and noninductive resistance 37 in multiple, through a winding of repeating coil BC to battery. Relay AS is therefore energized closing its alternate contact 38 and establishing a circuit for signal 11 traced from battery through said signal 11, alternate contact 38,

busy relay GB to ground, this series circuit contact 33 of RR,

potential upon its test:

1o; further sec- It will be om normal concausing the illumination of lamp 11 and the v I energization ofrelay GB. Relay GB theref fore closes its alternate ing ground to the particular cord circuitE busy and nonselectable.

contact 40 connect- Alternate contact 10 of GB is test contact 5 and rendering also closed, thereby affecting a step in the closure of the series conductor 9, so that when all of the relays GB, GB, etc., in the series are energized, ground will be con-' nected to the associated group contact 8 to render it busy. Of course as long as any relay GB of a series is at normal, this series conductor 9 is interrupted allowing its group to be selecte Referring again todistributer switch D, upon the connecting of the ground or busy potential to the connected test terminal 5,

a circuit for closing relay CL is established traced from said grounded contact 5, wiper T, normal contact 30,- conductor '60 and the winding of CL to battery. Relay CL therefore energizes closing its alternate contacts 61, 62, and establishing the continuity of the talking conductors of switch D. Although the initial circuit for relay AS of cord circuit E is interrupted when normal contact 35 of CL is opened, said relay AS is maintained energized by the alternate path traced over the heavily marked conductors including the calling line andback over the ti or primary talking conductor 62 and a wind:

ing of repeating c il RC g und. Thus a ane ielay is now under the control of the I for release relay BR traced from batterythrough winding 65 of RR, alternate contact .64, conductor 66, alternate contact 27 and normal contact-25 to ground. Relay ER is, therefore energized closing its lock- 110 ing contact 67 and thereby establishing a locking circuit to the said grounded normal contact 25. Alternate contact'23 of RR is also closed thereby connecting Winding 68 of BE in circuit with the grounded alternate contact 22 which establishes another energizing circuit for ER and prevents itsrestoration until plug C is withdrawn from its jack.

t The connecting operator in response to said signal 11 connects her telephone circuit (not shownlto ascertain-the wants of the calling subscriber and finding that connection is desired with substation A inserts the plug F of the selected cord circuit E into 25 a jack J of the Wanted line and thereafter depresses the plunger which actuates key contacts Upon connecting plug F to 'jack J a series circuit includin shunt relay SH, supervisory lamp 12 an cut-ofi' relay CO is established causing the energization of relays SH and CO and the illumination of lamp 12. This circuit may be traced from ground through the winding of CO third contacts of jack and plug, lamp 3 12 and the winding of SH to battery. Re-

. lay CO is thus energized to remove the substation control of itsline relay-LR. The energization of shunt relay. SH establishes a shunt circuit around the signal 11 causing 40 its efi'acement, this shunt circuit being established from-said lamp 11 alternate'contact 38, alternate contact 39, which is now closed, resistance 41 to battery while the original circuit through lamp 11 is interrupted at normal contact 39 and replaced through alternate contact 42. Thus enough" current is diverted through resistance 41 to cause the efiacement of said signal 11. Also,

- responsive to energization of SH, its altervnate contact 43 is closed establishing a circuit through normal contact 44 and the windings of electro-magnets CM and RI to battery causing their e'nergization. The energization of. clutch magnet CM is effective 5 to hold the operated key Kin its ringing position while the en'ergization of ringing relay RI closes alternate contacts 45, 46, to connect ringing conductors 47, 48 in circuit with the terminals of the called line. The

operator having actuated key K, a circuitj for call bell k is established traced from pul-'.

sating generator 13, through interrupter 16,

conductor 19, alternate contact 49,,winding 50 of disconnect relay DR, upper normal 6 contacts of keys H and G to conductor 47,

alternate contact 45, tip of plug F, jack J through the condenser and call bell is of substation A to ground. Due to the operation of interrupter wheel 16, ringing pulsations and battery are alternately connected 7c in circuit with the called line but due to interposition ofthe condenser at the called substation no battery flow is permitted.

Upon the'removal of the receiver at A,

in response to the call, a path for direct current is established at substation A and therefore as soon as the battery segment of interrupter 16 is connected in circuit with the called line a flow of current through winding 50 of disconnect relay DR is established, traced fronibattery through said in: terrupter 1-6 to conductor 19, and. then over the previously described path vi or ringing current to substation A returning over conductor Z ring contacts of jack and' plug, alternate contact 46, conductor 48 and alternate contact 150 of key K to ground. This flow of direct current causes the energization of disconnect relay DR whereby its normal contact 51 isinterrupted, opening the direct; 9o. shunt around the Winding ofrelay (1BR permitting the energization thereof whereby its normal contact 44 is interrupted, causing the restoration of ringin relayrRT-and clutch magnet CM. Relay 'Q RR allso'lopens its'contact 1552 upon its energizatiomtlilreby I preventing a denergization of tlie'i relay when disconnect relay DR subsequently re stores following therestoration of' Rlr" The two sub-stations A and A arejnow connected by a. conversational circuit which is indicated by the heavily marked conductors and due to the supervisory relay CS being included in the circuit of the called line, upon the said removal of the receiver at substation A this relay CS is energized closing its alternate contact 52 and thereby connecting resistance 53 in shunt of lamp 12 to'cause its efiacement.

Disconnection.

After the subscribers have finished conversation they will replace their receivers upon their respective switch-hooks, thereby causing the illumination of signals 11, 12 of cord circuit E, this being awell-known disconnect signal. The replacing of the receiver at substation A of course restores calling supervisory relay CS whereby its cuit which included shunt relay. SH, signal 12 and cut-off relay CO Relay C0 of course restores thereby restoring the substation control to its'line relay LE while the restoration of SH interrupts the circuit for relay GB at alternate contact 42, and by the interruption of said contact 42 interrupts the circuit for signal 11 causing its effacement. Upon deenergization of relay GB, its alternate contact 10 is interrupted, rendering the associated group contact 8 selectable so far as the ord circuit E is concerned. The interruption of alternate contact 40 of GB causes the interruption of the circuit of closing relay CL whereby said relay restores interrupting the circuit through the heavily marked talking conductors at switch D.

At this time relay BB is still energized with its normal contact 33 interrupted so that a reoperation of relay AS of the connected cord circuit is prevented. The closing of normal contact 69 of relay CL esy no tablishes. a circuit for disconnect signal -DS while the closing -of normal contact 64 of CL establishes a release circuit for relay SR this circuit being traced from battery through the winding of SR, alternate contact 31 of RR, normal contact 64, conductor 66, alternate contact 27, and normal contact 25 to ground. Relay SR, therefore energizes closing its alternate contact 29 whereby magnet SM advances the wipers in a secondary direction beyond the last contact of the row whereby they are automatically restored by spring tension as previously described in connection with the switch structure.

Upon restoration of PON, its alternate contact 27 is opened thereby interrupting the circuit for SE to cause its deenergization and rendering magnet SM inert. The interruption of this alternate contact 27 interrupts through winding 65 of relay RR but said relay is maintained energized through its other winding 68 and alternate contact 22 of STH until plug C is withdrawn, this energization of RR preventing another selecting operation of switch D until another call is answered. Upon withdrawal of plug C the series circuit including relays CO and STR is interrupted causlng the restoration of these relays,'the restoration of STE interruptin the locking circuit through winding 68 of R allowing it to restore. Switch D being at normal is now available for use in extending other connections.

' Over-mm switches.

I Assuming now that at the time the dis-" tributmg operator inserted jack J of the calling line,

plug G into .a all of the cord circuits to which it has access are busy, relay .STR is of course energized followed by the energization of'PR as before and the the locking circuitprimary adjustment of the switch coil further locking circuit for relay PR, it restores to normal interrupting the circuit for PM and by theclosing of its normal contact 25 establishes a circuit for SR as previously traced. Relay SR therefore energizes and closes a circuit through SM whereby the wipers receive a single secondary step which causes switch SON to interrupt its normal contact 28 and there being no locking circuit for relay SR (as test wiper T is not engaging a contact) said relay SR restores interrupting the circuit for SM. Thus the wipers are left off-normal and should be restored. To this end I provide the overrun switches and over-run relay ORR. The switch D having stepped beyond the last group of contacts in its primary adjustment, primary over-run switch, POR has been moved to its alternate position. Therefore when relay SR restores as referred to a circuit for ORR is established traced from ground at normal contact 33 of RR, normal contact 32, alternate contact 71, and the winding of ORR to battery causing its energization; Its alternate contact 72 is therefore closed establishing a circuit for CL traced from said grounded contact 72, alternate contact 73, conductor 74, conductor 60, and the winding of CL to battery. Relay CL therefore energizes closing its alternate contact 64 and establishing an. energizing circuit through winding 65 of relay RR over the previously described path'to ground at normal contact 25. RR therefore energizes closing its alternate contacts 67 and 23 thereby locking relay in its energized condition as before described. Normal contact 33 of RR is therefore interrupted interrupting the circuit for ORR and causing its restoration whereby itsw alternate contact 72 is interrupted allowing restoration of CL. Normal contact 69 of CL is therefore closed and a circuit for disconnect signal DS is established over a the previously described path from the alternate grounded contact 33. The closing of normal contact 64 of CL upon its said denergization establishes a release circuit for SR over the previously described path which may be traced from battery through the winding of SR, alternate contact 31, normal contact '64, alternate contact 27 and normal contact 25 to ground. Relay SR therefore closes a when all of the cord circuits to which a switch D has access are busy when the op- 20 multiples is seized by another distributer "greater than two-secon s.

erator inserts plug C in a jack,- lamp DS is 'lightedw'ithin a comparatively short time,

, course it is applicants intention to provide sufficient apparatus to take care of the incoming calls in a suitable manner.

Should switch D receive its primary adjustment to select a row of contacts having an idle contact set, and then before the wipers reach such an idle contact set (which we will assume-is the only one in the selected row)- said contact set or rather one of its switch D, over-run switch SOR is brought into play. In such case all of the contact sets of the selected row being busy, the wipers would be stepped beyond the last contact of the row due to the fact that the locking circuit for secondary relay SR is maintained closed through the busy test contact 5. Upon the switch reachingthisover-run point, contacts SOR are closed, so that when relay SR deenergi'zes, circuit for over-run relay ORR is closed traced from battery through the winding of said relay, alternate contact 171,'normal contact 32 to ground at normal contact 33. Relay ORR therefore closes its alternate contact 72 establishing an energizing circuit for relay CL traced from said grounded contact 72,

alternate contact 173, conductor 60 and the winding of CL to battery. Relay CL, therefore closes its alternate contact 64 and establishes an energizing circuit for the winding 65 of relay RR traced from battery to said winding 65, line contact 64, conductor 66, alternate contact 27 to ground at normal contact 25. RelayRR therefore energizes closing its locking contact 67 and also connecting its locking circuit 68 through alternate contact 23 to ground at alternate con: tact 22. As soonas relay RR energizes it interrupts its normal contact 33 thereby interrupting the circuit for ORR which restores and due to the interruption of its alternate contact 72, causes-restoration of relay CL. Relay CL being at normal and relay RR being still energized, a circuit for disconnect signal DS is established over the previously described path which includes normal contact 69 and alternate contact 33, and the operator observing this signal lmows that the associated distributing switch D has failed to pick up an idle cord. The switch D having of course restored to normal cannot be operated again until plug 0 is withdrawn from the jack to cause deenergization of relay STR and'thereby the restoration of release relay RR. The operator having observed the signal DS as already referred to may withdraw .plug 0 from the, jack' and immediately insert it again to try switch D once more, or she may use another plug 0 and associated distributing switch"D. v

' Fig. 3.

In Fig. 3, I have illustrated another embodiment of my invention, the connecting operation of the system shown therein differing in some respects from that of Fig. 1. In the system of Fig. 3, no distributing operator is required but a calling line has its circuit automatically extended-t0 a distributing switch D which switch extends the calllng line circuit to an idle cord circuit E In place of aplug C, a line selector LS is paired with each'cord selector B such an idle pair of switches LS and I) being selected and started through the medium of 'a master switch MS which is com mon to a group of lines and paired switches LS and D The present system is also readily applicable to installations having line clrcuits as B and cord circuits somewhat similar to E of Fig. 1, and in the present figure, that is Fig. 3, I have indicated the apparatus which corresponds to apparatus of Fig. 1, by like reference characters except for the suflix which has been added to the reference characters. In this way I believe the operation and similarity more readily apparent.

In applying the present system to installations having line circults as B of Fig. 1, the answering jacks, and line signals as LS may be removed and an additional contact 101 provided for the line relay. As I prefer to use 100 point selector switches LS I divide the lines into groups of 100 and for each such group of 100 lines, 10 line selector's LS are provided. The same switch construction asdescribed in connection with Fig. 2 is used for the line selector LS except that four contacts 102, 103, 104, 105, are

provided for each line circuit, and wipers P S T}, and W respectively are provided for cooperating with said contacts. Each group of 100 lines is then multiply connected to the contact sets of the associated ten line selectors LS. The lines are then dividedinto minor groups of 10 lines each, thesebeing preferably the 10 lines connected to each row of 10 contact sets and for each such minor group a group relay GR is provided being connected to the alternate contact 101 of the associated 10 line relays LR so that each relay GR may be energized upon initiation of a call over any of its associated 10 lines. Each group relay GR then has its grounded normal contact of the two figures will be.

106 connected to the corresponding group contact 107 so that when the group relay GR is energized it removes ground from the multiply connected contacts 107 of the 10 associated line selectors torender them selectable when energized by group test wiper GT The normal contact 101 of each line relay is connected to the corresponding line test contacts 104 of the 10 line selectors so that the started line selector will stop in its secondary adjustment when its test wiper T reaches the ungrounded test contact 10% of the calling line. Wiper W and the associated contact 105. are provided whereby an energizing path for the cut-off relay CO may be established when the calling line is seized, and also for operation of certain relays of the switches LS and D Master MS.

For each oup of 10 paired line and cord selectors LS and 1) respectively,- a master switch MS is provided, having wipers 108, 109 with a simple rotary motion and adapted to connect with a plurality of sets of con-- tacts 110, 111, said contact sets being equal in number to the number of associated paired selectors, which number is preferably 10, although more or less may be used, according to the traffic. A motor magnet MM and driving mechanism is provided for advancing the wipers 108, 109, in a step by step movement over the contacts 110, 111. An ofl-normal'contact ON is provided which is adapted to be closed upon the wipers leaving their normalposition, and an over-run contact OR is adapted to be closed upon the wipers stepping beyond the last or tenth contact of the set. A release magnet RM is also provided which is adapted to be energized when the wipers have stepped beyond the last contact of the row due to the closing of over-run contact OR, whereby a retaining pawl is withdrawn and the wipers '108, 109 restore to normal by spring tei1 sion where they engage the first set of contacts. Switch MS is preferably arranged to have its wipers 108, 109resting upon contacts leading to an idle pair of switches so that upon initiation of a call, such a pair of idle switches is started, switch. LS to select the calling line and switch D to select the first idle cord circuit E This starting circuit for the selector switches-is controlled through the normal contacts 112 of magnet RM, said contacts being connected'over common conductor 212 to the alternate contacts 113 of the 100 line relays LR of the group. As soon as the calling line has been connected through the medium of a pair of switches LS and D to a cord circuit E the master switch advancing relay AB is energized and closes a circuit for motor magnet hm whereby the wipers are advanced and relay AR maintained energized until an idle set ofcontactsiill, 111, are ea" gagd- J a Operation of 3.

ing line. Relay LE also closes alternate contact 101 to cause the energization ofits group relay GR whereby normal contact 106 is interrupted to remove ground from the group test-contacts 107 corresponding to the 5 roup of 10 contact sets or line terminals with which the calling line. is connected. Also upon energization of LIE-alternate contact 113 is closed establishing a starting circuit for the idle pair of selectors LS and D with which the wipers of master switch MS is then connected. This starting circuit is traced from ground at alternate contact 113, common conductor 212, normal contacts 112, 114, wiper 109 and the engaged contact 111, conductor 115, to connecting point 116, the starting circuit dividing at this point and including the primary relays PR ,'PR of switches LS and DE. The circuit vfor PR is traced from said point 116, conductor 117,

normal contact 118 and the winding PR to battery causing the energization thereof and establishing an operating circuit for the primary magnet PM from alternate contact 119. Magn et PM thereby. advances the Wipers a single primary step whereby group wiper GrT engages the first group contact 107. Assuming there is no line seeking connection in either the first or second minor groups, the first two contacts 107 will be grounded through the connected 'group'relays GR so that a locking circuit for primary relay PR is established from said grounded contact 107, wiper GT alternate contact'120 and the winding of PR to battery. Relay PR gized grounded contacts 107' so that magnet PM continues the primary adjustment ,of'the wipers until the ungrounded contact 107 is 01 course remains eneras long as wlper GT is engaging reached whereupon relay PR retracts its armature interrupting the circuit for magnet PM Wipers P S T W, have now 7 been advanced to a point opposite the third group of contacts 102, 103, 104:, 105, which is the sub-group containing the terminals of the calling line. The secondary adjustment ofswitch S is now efiected, this occurring responsive to the deenergization of PR. Upon saiddenergizatio'n of PR a circuit for secondary relay SR is established traced from ground at'normal contact 119 of PR,

alternate contact 121, normal contact SON,

naaaaec A and the winding of SR to battery. Relay SR therefore closes its alternate contact 123 establishing an energizing circuit for secondary magnet SM whereby wipers P S T, W, receive a single secondary step advancing them into engagement with the first set of line contacts. Assuming the line of substation A is the first line of this group seeking a connection, it will be the first line having its terminal 104. ungrounded so that upon wiper T engaging the first contact 104 of the row or group, due to the ground con nected thereto, a locking circuit for relay SR is established through alternate contact 124 so that magnet SM advances the wipers another secondary step and in fact continues this secondary adjustment until wiper T engages the test contact 104 of the calling line. Upon reaching this contact the circuit for SR is interrupted causing its deenergization whereby the circuit for SM is interrupted and the switch. wipers rendered inert, and in engagement with the terminals of the calling line. Thus, it will be seen how a calling line is selected by the line selector.

We will now take up the operation of the cord selector D Returning to the starting circuit and to point 116, the ground connec-. tion over conductor 115 is extended toward the right over conductor 126. normal contact 127, and the winding of PR to battery causing the energization of relay PR whereby its alternate contact 128 is closed establishing an operating circuit for primary magnet, PM Magnet PM upon its first energization advances the wipers of switch D a single primary step whereby group test wiper GT engages the first group contact 8 which we will assume has a ground or busy potential thereon due to the busy condition of the associated cord. circuits E Therefore a locking circuit for PR is established from said grounded contact 8 through alternate contact 129, and the winding of PR tobattery so that magnet PM advances the wipers another step and in fact continues this primary adjustment as long as wiper GT is engaging busy contacts 8 Upon reaching the third contact 8 which we "will assume has an idle cord circuit in its associated sub-group, circuit for PR is interrupted causing the deenergization thereof, and the interruption of the op crating circuit for PM whereby anyjfurther primary adjustment of the switch D is prevented. Thus by the primary adjustment of switch I), a sub-group of cord circuits with an idle circuit having been selected, a secondary adjustment of the switch is brought about to select such an idle cord circuit in this selected sub-group. lherefore upon deenergization of PR its normal contact 128 is'closed establishing a circuit for secondary relay SR traced from grounded normal contact. 128, alternate contact 130,

contact SON and the winding of SR? to battery. Secondary relay SR is therefore energized closing its alternate contact 131 and establishing an operating circuit for secondary magnet SM whereby wipers P, T", S are advanced a single secondary step to engage the first set of contacts 5 6 7 Assuming this first set of contacts leads to a busy cord circuit E the test contact 5 thereof has a ground or busy potential connected thereto so that a locking circuit for SR is established traced from this grounded contact 5 wiper T alternate contact 132, normal contact 133, and the windin of SR to'battery. Upon this first secon ary step of D contact SON is interrupted just before wiper T connects with contact 5 to prevent shunting the cut-01$ relay of a call ing line connected therewith, by the ground from normal contact 128. Therefore, this secondary adjustment of the switch is continued until wiper T reaches an ungrounded or idle test contact 5 which we will assume is the one leading to the cord circuit E shown. Relay SR therefore loses its energizing circuit and interrupts the circuit for 8M rendering the wipers inert.

lhus the calling line having been selected and an idle cord circuit E having been selected, the connection will be completed by closing relay GL and the line signal 11 operated. This is brought about upon the deenergizationof SR by a circuit for answering supervisory relay A8 and 37 in multiple, conductor '36 contact 7 wiper S normal contacts 134, 135, 136, to ground whereby relay A5 is energized closing a series circuit including lamp 11 group busy relay GB closing relay GL and cutoil relay CO this circuit being traced from battery at E through lamp 11 alternate contact 138, relay GB, conductor 139, contact 5 and Wiper T normal contacts 132, 140, winding of CO to ground. These three relays CO GL and GB, are energized and signal 11 is illuminated to indicate the call to the operator. The energize.- tion of GB eltects a step in the closing or the series circuit 9 toward rendering the corresponding group contacts 5 busy in a manner as already. explained. The energization of CO causes the interruption of the circuit for line relay'LR thereby closing normal contact 101 to render the associated test contact 104 unselectable, while the interruption of alternate contact 101 restores group relay GR, (providing no other line in the group of 10 is calling.) to restore the associated group contact 107 to a grounded or non-selectable condition. The interruption of alternate contact 113 of LB removes ground Jtrom the starting conductor 212 and nor ire mal contact 112 until some other line in the group of 100.is calling. It will alsobe noted that due to the connection of battery to enof relay GL closes alternate contacts 141 and 142, thereby extending the talking circuit of the calling line to the selected cord circuit E whereby supervisory relay AS is included in circuit with the calling line and maintained energized by current flowing over the heavily marked conductors. Also upon energization of GL release relays BB and BB are energized, the circuit for BB being traced from battery through the wind- .ing thereof, alternate contacts 143, 121 to ground at normal contact 119 causing the energization of BB whereby its alternate contact 144 circuit for itself so that it will remain energized until the switch is restored and FUN restored. The circuit for BB is traced from 1 battery through the winding thereof, alternate contact 145, 130 to ground at normal contact 128 whereby alternate contact 146' of BB is closed establishing a locking cir: cuit for itself so that BB remains energized until switch D is restored and alternate contact 130 of IPON interrupted.

The connection from the calling line to an idle cord circuit E having been completed, the master switch MS has its wipers advanced to the next idle .pair of selector switches, this being brought about by the energization of relays BB and RR. That is upon the closing of alternate contacts 148, 136 of these relays, or in fact either one of these contacts, ground is connected to conductor 149 whereby a circuit for advancing relay AB is established causing said relay to close its alternate contact 150 whereby motor magnet MM advances the wipers 108, 109 a single'step. then engaged lead to a busy pair of selectors LS, 'D, relay AR of course remains energized and magnet MM advances the wipers another step. Should all of the remaining sets of contacts 110, 111, be busy, upon the wipers 108, 109, advancing beyond the last contact of the set, over-run contact OR is closed establishing an energizing circuit for the release magnet'RM which is therefore locked through its alternate contact 151 and upon the energization of RM a retaining pawl is withdrawn allowing the wipers 108, 109 to be restored to normal by spring tension, in which position they are engaging the first set of contacts 110, 111. If this first set of contacts is idle, relay AR of course does not energize and wipers remain inert, but if the first set of contacts are busy relay AR again energizes and. the magnet MM advances the wipers until an idle set of contacts is reached. As

switches LS and D are restored so that the. $6

already pointed out, relays BB and BB remain energized until their respective conductor 149 is maintained grounded and finding the is closed, establishing a locking.'-

If the set of contactsv the circuit for relay AS illumination thereof; Thus,

therefore the non-selectable until the connected pair of switches LS and D are again at normal.

The operator in response to the lighting of calling signal 11, connects her operators telephone set (not shown) in bridge of the cord circuit E and finding the substation is the desired one, she tests the jack J thereof in the usual manner by touching the tip of the plug to'the sleeve of the-jack and line idle she inserts plug F to connect with the called line. Responsive to this connection a series circuit including relay SH lamp signal 12 and cut-ofi relay CO is established in a manner as described in connection with Fig.1, wherebysignal 12 is lighted and due to the closing of contact 39 resistance 41 is connected in shunt with signal 11 thereby efiacing said signal. Also upon energization of SI-I its alternate contact 154 is closed connecting disconnect lamp DL in multiple with lamp 11 and resistance 41 but suflicient current does not flow through this lamp DL to cause its illumination until the. calling subscriber restores his receiver to deenergize rclay AS. The operator now depresses the proper ringing button whereby the bell of the called substation is operated and the automatic disconnection of the ringing current isefiected upon response from the called substation in a manner as described in connection with Fig. 1. Upon response of the called subscriber at substation A calling supervisory relay ing the efl'acement of the signal 12 The two substations are now connected for conversation, the talking circuit being traced over the heavily marked conductors.

Disconnection in F 9. 3.

substation A causing relay CS to de'enerlamp 12 while at T interrupts causing its deenergization and the interruption of its contact 138. This interruption of contact 138 disconnects lamp 11 and resistance 41 from in shunt with disconnect lamp DL so that gize and again light signal the replacing of the receiver said lamp DL is connected in series with i the relays GB, GL and CO causing the 12 being illuminated'the operator knows that the subscribers have replaced their receivers and removes plug F from its jack, thereby interrupting the series circuit through relays SH and CO causing their deenergization. The restoration of SH by the interruption of its alternate opens the and CO causing these three relays to restore, the restoration of GB removing the busy potentlal from the associated group contact 154 circuit through relays GB, CL

lamps DL and nasa -lee contact 8 Upon restoration of GL the heavily marked talking conductors are interrupted so that upon restoration of the wipers of the pair of switches LS and D any existing connections over which these for SM whereby the wipers are advanced to be automatically released as described in connection with the switch mechanism. Upon switch LS returning to normal, alternate contact 121 of PON is interrupted, thereby interrupting the circuit for SR which restores and switch LS is therefore at normal.

Now as to tne restoration of cord selector D its secondary relay SR is energized upon said de'e'nergization of relay CD, the circuit being traced from battery to the winding of SE of alternate contact 133, normal contact 145, alternate contact 130 to ground at normal contact 128. Relay SR therefore closes its alternate contact 131 establishing a release circuit for SM so as to cause resto ration of switch 1)". Upon restoration of the wipers to normal, alternate contact 130 of-PUN is interrupted thereby opening the circuit for SR? and BB effecting the deenergization of these relays whereby switch D is at normal. Relays R3 and BB upon their deenergization disconnect ground from the conductor 145 leading to the master switch MS whereby the associated pair of selectors LS and D are available for use in establishing other connections. Upon the said deenergization of CO the line of substation A is available for use in establishing other connections.

The system of Fig. 3 is also arranged to cause the automatic restoration of a pair of selectors LS and L should such a pair be started and fail to connect a calling line and a cord circuit. 7

For instance should the receiver at substation A be removed and immediately replaced, the associated line relay LE will be energized suiiiciently to ground the common starting conductor 212 and thereby start an idle pair of selectors LS and D but due to the fact that relay LE is only momentarily energized, ground is again connected to the group contact 107 associated therewith and individual test contact 104 so that this line which started a line selector is non-selectable. in such case, should no other line of the group be calling, all of the group contacts 107 are in a grounded or non-selectable condition so that the primary adjustment of switch LS is continued until the wipers have passed beyond the last group of the switch and the primary over-run contact FUR isfiw closed. Upon the switch reaching this point, and relay PR having deenergized due to the interruption of its maintaining circuit through the group wiper GT a circuit for secondary relay SR is closed from grounded normal contact 119 of PR over the previously described path through SE to battery whereby SR is energized causing an operation of SM. Upon the first secondary step of switch LS, the initial enerso gizing circuit for SR is interrupted at SON and test wiper T failing to connect with a contact 10 1, relay SR immediately deenergizes interrupting the circuit for SM and preventing any further secondar Vance of the switch for the present. n the meantime assuming the cord selector D has selected an idle cord circuit E and its relay SR has deenergized, a circuit including closing relay GL and relay GB of cord circuit so E is established from ground at FOR the windin oi": GL normal contacts 140, 132, wiper and contact 5 conductor 139, the winding of GB, alternate contact 138 (which is closed due to the momentary enere5 gization of A55 through normal contact 135 of SR lamp 11 to battery. Relay UL therefore energizes closes circuit for relays RR and BB in a manner as previously described whereby these relays are energized and locked up as already pointed out. Upon said energization of GL its normal contact 134 is interrupted thereby interrupting the circuit through A8 which deenergizes due to the fact that there is no substitute energizing circuit therefor over a calling line. Therefore relay AS having failed to remain energized its contact 138 interrupts, again opening the circuit for GL which re stores to close ener izing circuits throu h are b a) (D lays SF and SE in manner as already described. That is relay SR is energized due to the closing of normal contact 1 13 of GL while SR is energized due to the sins ing of normal contact 145 of GL lays SR and SR therefore close release circuits through the corresponding secondary magnets whereby switches LS and D have their wipers advanced and then restored in a manner as previously described. Upon restoration of the wipers to normal relays SR BB BB and SR are returned to normal and the switches LS and D are therefore available for establishing other connections. Although the operation justdescribed causes a momentary flash of signal 11 the operator can be instructed to pay no attention to such signal or even should she connect her operators telephone circuit with the associated cord circuit she would 13 Said re- 115 this over-run position,

receive no response and would know that no connection has been established.

Another operation of the system of Fig.

3 which may sometimes occur, is Where a,.

call has been initiated and the calling line selected by a line selector LS but the paired cord selector 1) fails to select a cord circuit E either because all the cordcircuits to which it has access are busy or because the primary adjustment of the switch D brings its wipers to a group of cord circuits having a cord circuit of the group idle when the-group was selected but in which this idle cord circuit is seized by another'selector D before the present selector D in its secondary travel reaches the terminals 5 6 7 thereof. k L

Assuming now that a call has been 1n1t1- ated at substation A and that, line L has been selected by a switch LS butthat the cord circuits to which the paired selector D has access, are all busy. In this case the primary adjustment of switch D is. continued until the wipers are stepped beyond contacts and switch the wipers reaching and the circuit for PR being interrupted,this relay PR deener'gizes closing its normal contact 128 and thereby closing the circuit for Slit which energizes and causes magnet SM to advance the wipers a single secondary step and thereby interrupting contact. SON to open the initial energizing circuit of SR Wiper '1 having failed to engage a grounded contact 5 upon thi first secondary step, relay the last groupof bank POR is closed. Upon SR restores preventing any further secvondary ad ustment of the switch wipers for the present. i

Upon the switch I) reaching its prlmary over-run. position, contact 71 of POR is closed whereby a circuit for over-run relay ORR is' established traced from battery through the winding thereof, alternate contact 71 to ground at normal contact 136. Re-

lay ORR therefore energizes closing its alternate contact 7 2 and establishing a series cirwinding of CO to ground. Said relays CO i so cuit including CO and GL traced from battery through said contact 72 alternate contact 7 3 conductor 162, normal contact 140, winding of CL, wiper W, contact, 105, the

CL are therefore energized, the energization of CO causing the restoration of LR and the interruption of the starting circuit overyconducto'r 212 (providing no other line is calling at the time) while the energization of CL causes the energization of BB and BB as already pointed out. Upon energization of BB and the interruption of its ,normal contact 136, relay ORR restores thereby interrupting the series circuit through relays CL and CO so that these relays restore, the restoration of GL effecting he energization of the two secondary whereby the switches LS and D are at normal and available for other use.

Although the first pair of selectors LS and D started failed to extend th calling line to an idle cord circuit E the present system is so arranged that a second pair of suchswitches are automatically started to attempt to effect such a connection. That is, as soon as relays RR RR are energized conductor 149 leading to master switch MS 1 is grounded thereby causing switch MS to advance its wipers to the next idle set of contacts. Therefore upon restoration of C0 of the calling line when relay 'OR R was denergized as pointed out above, the line circuit st ll being closed at substation A line relay LE thereof is again energized and a starting circuit including conductor 212 is again closed to start the next set of idle selectors'LS and D Should this sec- 0nd pair of switches fail to establish a connection a third pair will be started and so on until one of such pairs of switches will connect the calling line with an idle cord circuit E Another non-selecting operation of a pair of started switches LS and D may occur in which the line selector will pick up the calling line but the paired cord selectors D will recelve its primary ad ustment to select a group of contacts having an idle set of contacts but before the wipers of this switch D in their secondary adjustment, reach this set of contacts, some other switch D having access to the connected cord circuit E seizes these contacts and renders them busy. In such case, assuming there is no other idle set of contacts in the group, the secondary adjustment of the wipers is continued until they have passed into a secondary over-run position. In this case switch SOR is closed connecting relay ORR in circuit to cause the restoration of the paired switches LS and D in a manner similar to that described when the over-run switch POR is operated. Therefore switches LS and D are restored to normal, and master switch MS advances to the next set of idle contacts to start another pair of switches to connect the calling line with an idle cord circuit D Fig. 4. Fig. 4 illustrates a cord circuit E adapted for use in place of cord circuitE, the circult of Fig. 4 differing from cord circuit E 1n that'but single party line ringing is provided and without any automatic control. The control of the supervisory signals escapee of E is the same as that of E and I have indicated the like parts by like reference characters except for the use of a diiferent suffix. The operation of IE will be apparent in view of the description of E and it is thought that no further reference to E is necessary for an understanding thereof.

Although in illustrating my invention 1 have shown a plurality of batteries, it is to be understood that these batteries may be one and the same in any exchange in accordance with common practice and although I have shown mechanical circuit interrupters on the operating magnets of the switches, I contemplate using either such interrupters or a source of alternating current. Furthermore, I am aware that many changes in the circuit arrangements will readily suggest themselves and therefore I do not desire to be limited to the exact arrangements as shown but alm to cover all that which comes within the spirit and scope of the appended claims.

What I claim as new and desire to secure by United States Letters Patent is:'

1. An automatic two-dimension call distributing switch comprising contacts arranged in groups and coiiperating wipers, link ClICllltS extending from said contacts, multi le connections for said contacts where y the link circuits may be rendered busy, a starting circuit for said switch, and means whereb if all of said circuits are busy when sai switch is started said wipers are operated to test all of said groups and automatically restore by both movements thereof. t

2. An automatic two-dimension call distributing switch comprising contacts arranged in groups and cooperating wipers, link circuits extending from said contacts, other connections whereby the link circuits and contacts may be rendered busy, astarting circuit for said switch, means responsive to said starting circuit for causing a primary adjustment of the wipers to'test all of said groups, and means efiective if all of said groups are busy for automatically causing a secondary operation and restoration of sald wipers to normal.

3. An automatic two-dimension call distributing switch comprising contacts arranged in groups and cotiperating wipers, a primary magnet, a secondary magnet, link circuits extending from said contacts, other connections rendering all of said contacts and link circuits busy, a starting circuit for said switch, means responsive to said starting circuit for causing an automatic operation of said magnets whereby said Wipers test said contacts for an idle circuit and are thereafter automatically restored to normal.

4. An automatic two-dimension call distributing switch comprising contacts arranged m groups and coiiperating wipers, a

primary magnet, a secondary magnet, link circuits extending from said contacts, other connections rendering all of said contacts and link circuits busy, a starting circuit for said switch, means responsive to said starting circuit for causing an automatic operation of the primary magnet whereby said wipers test said contacts for a group having an idle circuit, and means efiective when none such idle circuit is found for causing an automatic operation of the secondary magnet to restore said wipers to normal.

5. A telephone system comprising telephone lines, answering jacks therefor, operators link circuits including answering plugs, other links circuits, automatic switches responsive to the insertion of the answering plugs into the jacks of calling lines for extending the operators link circult of a plug to one of said other link cirlink circuits, a disconnect signal for said answering plug, and means for operating said signal upon failure of said switch to find an idle link circuit.

7. A telephone system comprising telephone lines, answering jacks therefor, op-

erators link circuits includinganswering plugs, other operators link circuits including calling plugs, automatic switches equal in number to said first link circuits, and means responsive to the insertion of an answering plug into the jack of a calling line for causing one of such switches to extend the circu1t of the operators link circuit of said plug to an idle one of said calling link circuits.

8. A telephone system comprising a link circuit provided with an answering plug, a second link circuit provided with a cal mg plug, and means responsive to the insertion of said answering plug into the jack of a calling line for automatically selecting and connecting said second link circuit to said first link circuit.

9. A telephone system comprising a plurality of A-operators" link circuits provided with answering plugs, a plurality of B-operators link c1rcuits provided with calling plugs, and automatic means responsive to the insertion of a calling plug of one of said first link circuits into the jack of a calling line for connecting said link circuit to an idle one of said B-operators links circuits.

.10. A telephone system comprising an A- operators link circuit and B-operators link circuits, manual means for directly connecting said A-operators link circuit to a calling line, and automatic trunk selecting means individual to the A operators link circuit responsive to said connection for automatically selecting and connecting said A-operators link circuit to an idle one of said B-operators link circuits. 11. A telephone system comprising a plurality of link circuits of one character and a plurality of link circuits of another character, manual means for interchangeably connecting said first link circuits and calllng subscribers lines, automatic means individual to said first link circuit andresponsive to said connections for automatically interchangeably selecting and connecting the said first link circuits to idle ones of said other link circuits, and supervisory signals for both of said link circuits.

'12. A'telephone system comprising a link circuit, other link circuits, manual means for directly connectin said first link circuit to a calling subscrlbers line, and auto matic means responsive to said connection for connectin said link circuit to an idle one of said ot er link circuits.

13, A telephone-system comprising a calling subscribers line, a plug-ended link circuit, other link circuits, manual means for connectin said first link circuit to said calling su scribers line via saidplug, and automatic means responsive to said connection for connecting said link circuit to an idle one of said other link circuits.

- 14:. A telephone system including a calling and a called subscribers line, an operators plug-ended link circuit, a second link circuit, means responsive to the manual connection of said first link circuits to said calling line for automatically completing connection between said pair of link circuits, means for connecting the other of said link circuits to said called ,line, and means responsive to the disconnection of said last link circuit from said called line for automatically interrupting connection between said pair of link circuits.

15. A telephone system including a calling subscribers line and a called subscribers line, an opei'ators link circuit, a second operators link circuit, means responsive to the manual connection of said .first link circuit to said callingline for automatically connecting said first link circuit to said second link circuit, means for connecting said second link circuit to said called subscribers line, a supervisory signal for said first link circuit operable when said second link circuit is disconnected from said called subscribers line, and operator-controlled means for then restoring said first link circuit.

16. A telephone system including a calling subscribers line and 2. called subscrib- I grou nection to said calling subscribers line,

other operators link circuits for connection to said called subscribers line, automatic means associated with said first link circuit and responsive to the manual connection of said link circuit to said calling subscribers line for connecting said link circuit to an idle one of said other link circuits, means for connecting the selected link circuit to said called subscribers line, a supervisory signal for said first link circuit, and means for operating said supervisory'signal when said selected link circuit is disconnected from said called line or if said automatic means does not find an idle link circuit.

17; A telephone system including a calling subscribers line, an automatic switch, 'l1nk c1rcu1ts divided into groups and accessible to said automatic switch, manualmeans for connecting said switch to said calling subscribers line, and means responsive to said connection for operating said switch to test said link circuits by groups until an idle group is found and for then testingtthe link circuits in the selected group until an 'idle link circuit is found.

18. A telephone system comprising a calling subscribers line, an automatic switch, link circuits divided into groups and accessible to said switch, a contact for each of said groups,'and means associated with each of link circuits for making its respect1ve contact test busy, and means re sponsive to the manual connection of said switch to said calling subscribers line for operating said switch to test said link cir cuits by groups. 7

19.; A telephone system comprising a callingsubscribers line, a link circuit, an automatic switch for said link circuit for extending. a connection therefrom, means responsive to the connection of said link circuit to said calling subscribers line for operating said automatic switch, independ-- ent means. for releasing said automatic switch, and means for preventing a reoperation of said automatic. switch until said link circuit'is disconnected from said line.

20. A telephone system including a calling subscribers'line and avcalled subscribers line, a pair-of plug ended link circuits,

automatic means responsive to the manual connection of one of said link circuits tosaid calling subscribers line for establishing connection between 'said link circuits,

means for connecting the other of said link circuits to said called subscribers line, and means responsive to the disconnection of said last link circuit from said called subscribers line to interrupt said connection between said llnk c1rcu1ts.

21. A telephone system including a callingsubscribers line and a called subscriber s hne, an operators hnk circuit, a second operators link circuit, manual means for directly connecting said link circuits to sald calling and called subscribers lines respectively, automatic means for establishing connection between said link circuits, a pair of supervisory signals for sald second link circuit under the control of the calling and called subscribers, and a disconnect signal for the said first linkcircuit responsive to the disconnection of said other link circuit from said subscribers line.

22. A telephone system including a calling subscribers line and a called subscribers line, an operators plug-ended link circuit, a second operators plug-ended link circuit, means for connecting said link circuits to said calling and called subscribers lines, respectively, automatic means for establishing connection between said link circuits, :1

pair of supervisory signals for said second 2 link circuit under the control of the and called subscribers, and a, disconnect signal for said first link circuit responsive to the disconnection of said second link circuit from said subscribers line,

Signed by me at New Yorkin the county of New York and State of New York in the presence of two witnesses. ALFRED H. DYSON, Witnesses: 7

W. F. HOFFMAN, G. E. MUELLER.

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