US1273189A - Telphone system with automatic ringing disconnect. - Google Patents

Description

F. SCHOENWOLFi TELEPHONE SYSTEM WITH AUTOMATIC RINGING DISCONNECT.

APPLICATION FILED NOV. 21. I914.

ll WW 1 Wm Patented July 23, 1918.

fiZUEHZER FZ ELThUEHZ/Z/UZZ ing and called substations A and spectively each terminating in line circuits rupts the link or cord talking conductors and rnwrrnn "STATES rarnnr or rrpn.

' FRED SCJEECENWOLF, 0E CHICAGO, ILLINOIS, ASSIGNCR TO KJELIOGG SWITCIIBOARD AJSIII SUPPLY COMPANY, 0T CHICAGO, ILLINCIS, A CCRJPORATICN 0R IIIIJJEN 01$.

I TELEPHONE SYSTEM WITH AUTOMATIC RING-INC DISCONNECT.

IRIRJLSR.

Application filed November a7, 1914:. Serial No. Warsaw To all whom it may concern Be it known that I, FIRED SononNwoLr, a citizen of the United States of America, resident of Chicago, county of Cook, and State of Illinois, have invented certain new and useful Improvements inj'Iel'ephone Systems with Automatic Ringing Disconnect, of which the following is a specification.

My invention-relates to telephone systems and has to do more particularly with auto matic ringing systems such as are provided for operators cord circuits, one of the principal objects of my invention being to provide an improved circuit arrangement whereby the application of ringing current to the called line is interrupted and a disconnect signal given should the calling sub scriber replacehis receiver prior to receivin a response from the called substation.

n the accompanying drawing I have illustrated the preferred embodimentof my invention, the system shown includin callrehaving theusual line relay LR, cut-ofi' relay CO and line jacks. The line circuits shownare What are known as multiple lamp circuits in which a line lamp is provided for each jack so that when a call is initiated a. line signal appears before'each of the calling line jacks and any one .of a plurality of'operators may seize this call preferably to the exclusion of others.

The preferred form of cord circuit C is'arranged for interconnecting the telephone lines and includes an answering plug AP and calling plug ClP connected by talkin conductors indicated by heavily marke lines. In answering a call an. operator inserts an answeringplug AP into a line jack whereby the high resistance test relay 'I is energized to connect the answering supervisory relay AS in circuit with the cut-olf relay CO so that relay AS is energized and connects the operators telephone 0 in circuit with the cord and thus with calling line. The answeringvtip rela'y'A'll also energizes to prevent the premature lighting of the answering supervisory lamp AL. In extending the call to the wanted line the operator inserts the calling plug CI whereby the calling sleeve relay CS energizes to again disconnect the operators telephone Specification of Letters Patent.

Patented July as, rare;

from the cord circuit. depresses the proper plunger of the ringing key RK'which connects the proper ringing generator by the common contacts of the key, causes an energization of a ringing con- Theoperator then,

trol relay RC followed by the periodlc en- A ergizations of an interrupter relay IR by a circuit through the interrupter I. "When the subscriber responds to the call a calling tip relay C'I energizes interrupting the locking circuit for the ringing control relay RC to stop further application of ringingcurrent and efface the calling supervisory lamp CL.

Should the calling subscriber replace his receiver prior to the response of the called subscriber link disconnect relay IJD energizes and in view of the fact that the lock mg circuit for the ringing control relay RC is controlled through contacts of relay LD, the ringing control relay dee'nergizes and prevents further application of ringing current to the called line.

'Ihe energization of relay Ll) also interdevices employed in the preferred embodiment of my invention and their functions, Iv

will now describe more in detail the operation of the system shown.

A subscriber at substation A desiring to call, removes his receiver to establish a cir-' cuit for the corresponding line relay LR whereby the line signals before the different associated jacks are lighted. 'Ihe first oper ator to seize the call by the insertion of an answering plug AP in one of the calling line jacks, connects high resistance test rela I and cut-ofl' relay COin series effectmg the energization of T. The closing of alternate contact I of relay 'I connects the comparatively low resistance answering sleeve relay AS in series with cut-0d relay "the shunting of its winding b control relay RC traced from through the winding thereof, alternate con- CO whereby relay AS energizes closin its,

alternate contact 2 to connect its win ing directl to the sleeve strand of the cord indepen ent of the contact of the test relay, Therefore should relay T restore due to paratively low resistance of A relay AS still remains energized through ts locking contact 2. Due to the flow of current throu h the windings of AS and T over the ca ling line and through theanswerlng tip relayAT, said relay AT energizes to interrupt its normal contact 3 and prevent a premature lighting of the answering supervisory lamp L and premature energlzation of the link disconnect relay-LD. Also responsive to energization of AS its alternate contacts 4, 5 are closed to connect the .operators telephone 0 in bridge of the talkin conductors of the. cord and thus to the ca ling telephone line.

Should a second operator lnsert a plug APinto another jack of the callin line subsequent to the insertion ofthe rst plug, the test relay T of this second cord does not energize due to the shunting of lts winding by the relay AS of the first cord so that the second operator is unable to communicate with the calling subscriber because .her telephone set is not: connected. Therefore this second operator again withdraws her answering plug AP The first operator having ascertained that connection is desired with. substation B tests a jack thereof in the usualmanner and finding the line idle inserts the calling plug -CP in a jack thereof. This act connects calling sleeve relay CS and cut-off relay CO in series causing their energization, the energization of CO removing the substation control of its line signals and extend ing the connected jack and cord to the called line. The energization of CS by interrupting its normal contacts 9, 10, again disconnects the operators telephone from the cord. The operator now depresses the proper plunger by ringing key RK whereby the associated generator is connected to the ringing conductor 6. The actuation of the ringing plunger to its fully depressed posi- 8 which are closed while the plunger is 7 fully depressed but not when in its intermediate position. The closing of alternate contact 8 establishes a circuit for ringing battery tact 8, normal contacts 11, 12, and alternate contact 13, to ground. Relay RC therefore energizes closin its alternate contact 14 to establish a direct locking circuit for its winding through normal contact 11, and 12 and alternate contact 13 to ground.

It will be noted that the locking circuit for ringing control relay RC is traced will be described; the com-' tip relay C through. normally closed contacts of relays LD and CT thereby placing the disconnection of ringing current under control of both the calling and called substations as Relay RC having energized, interrupts its normal contacts 17, 18 to interrupt the talking strand and closes its alternate contact 19 to establish an operating circuit for interrupter relay IR through interrupter I. Relay IR is therefore periodically energized to alternatel connect ringing current and in circuit with the called line by action of its contacts 20, 21.

Upon response of the called subscriber and the first followin deenergization of IR acircuit for tip re ay CT- is established traced from ground through the winding thereof, normal contact 20, alternate contact 22, over the line and returning through the winding of CS to battery. The resulting energization of CT efi'ects an int'errix tion of its normal contact 12 which it wil {be remembered is included in the locking circuit of RC. Therefore relay RC deenergizes opening its alternate contact 19 and maintaining the interrupter relay IR inert. The closing of the normal contacts 17, 18 establishes the continuity of the talking circuit between the two substations.

Assuming now that the connection has been extended to the called line and that its substation was being rung, as before described, but that the calling subscriber replaces his receiver prior to receiving a re- I sponse from the called substation. In such case the circuit for answering tip relay AT is interrupted causing its restoration whereby a circuit for link disconnect relay LD and supervisory lamps AL, CL is established. 1015 The circuit for relay LD is established from battery through winding thereof, normal contact 3 and' alternate contacts 26, 13-to ground. Relay LD therefore energizes to interrupt the talking conductors of the link and thereby operatively disconnect the link from the calling line. Although this energization of LD interrupts the initial energizing circuit for AS and T by the opening of normal contacts 27, said relays AS and T are maintained energized through alternate contact 27 to ground over contacts 26, 13. The ground connection from alternate contact 13 to normal contact 3, previously traced, is also effective to li ht supervisory lamp AL and the closing 0 alternate contact 11 of relayLD lights calling supervisory lamp CL over a circuit traced from battery through CL, alternate contact 11, normal contact 12 to ground at alternate contact 13. The operator having observed the two signals AL .and CL lighted, withdraws plugs AP and CP from their respective jacks, the withdrawal of plug CP causing the restoration of relay CS whereby its 415 lighting of lamps AL and CL and the ener- Lat/area alternate contact 13 is interrupted. As reas already described. The operator will now lays LD, T and AS are held up over a circuit through this alternate contact 13, it will be seen that they are restored when said contact is interrupted.

ltwill be observed that when the subscriber A replaces his receiver prior to receiving a response from the called substation and relay LD energized to operatively disconnect the cord from the calling line, cutofi' relay CO thereof restored so that the line of substation Awas available for immediate recall. Therefore if the subscriberat substation A desires to initiate a recall without awaiting the removal of plug All? from its jack, by again removing the receiver, line relay LR is energized to light the associated line signals so that the same or another operator may take the call. 4

When a connection has been efiected between substations A and B in a manner as above described and both receivers are ofl their switch-hooks, establishing a conversational circuit, the replacing of these receivers will light supervisory lamps AL and CL. Assuming the subscriber at B is the first to replace his receiver the circuit for relay CT is interrupted causing the closure of its normal contact 12 and establishing a circuit for lamp CL from ground at alternate contact 13 of CS, normal contacts 12, 11, 14:, 7 and lamp CL to battery. The replacing of thereceiver at substation A causes the deenergization of AT followed by the energization of Ll) and the lighting of lamp AL withdraw the two plugs restoring the apparatus to normal.

' It will be noted that relay Ll) is a slow restoring type, this being to prevent the seizing of a recall by more than one link circuit. That is,- assuming a connection is es tablished between substations A and B and that after conversation the subscribers have replaced their receivers to bring about the gization of LD. Should the calling subscriber at A initiate a recall prior to the removal of plug AP, the associated line signals will of course be lighted and should another operator than the one which controls cord C seize this call, upon the withdrawal of plug CP of C the locking circuit for relays LD, T and AS is interrupted at alternate contact 13 of CS. Now if relays LD, T and ASwere fast relays, and relay Ll) should restore prior to T and AS it will be seen that due to the closing of normal con tact 27 of LD, relay AS would remain locked up over the sleeve strand and therefore the operator of cord C would have her telephone connected to the calling line in multiple with the telephone of the other op erator who has seized the recall. But due to the slowness of relay Ll), relays AS and service and instantaneous disconnect and recall are provlded, together with automatic ringing which when applied to a called line may be interrupted by a control exercised from either connected substation together with means for establishing the usual disconnect signal of two supervisory lamps.

lln Working out-my invention l have applied it to a preferred form of cord or link circuit but I contemplate using it in con nection with other circuits than that shown. lt will also be apparent .that changes and modifications will readily occur to those skilled in the art after becoming familar with my invention and therefore it do not de sire to be limited to the exact structure as shown and described but aim'to cover all that which comes within the spirit and scope of the appended claims.

Having described my invention, what ll claim as new and desire to secure by United States Letters Patent, is:

1. A telephone system comprising telephone lines, an operators link circuit for interconnecting said lines, operator controlled means for applying ringing current and continuing such application to the called line, and means for interrupting such application of ringing current by a control ex- -ercised at both the calling and called subcontrolled means for initiating the operation of said means, and means controlled by both supervisory relays for interrupting said application of ringing current.

v 3. A telephone system comprising telephone lines, an operators link circuit for interconnecting said lines, a relay at each end of the link circuit operable over the telephone line connected at that end, means for applying ringing current and continuing such application to the called line, operator controlled means for initiating the opera tion of said means, and circuit connections including contacts of both of said relays whereby said application of ringing current may be interrupted by a control exercised at both the calling .and called substations.

4:. .A telephone system comprising telephone lines, an operators link circuit for interconnecting said lines, means for applying ringing current and continuing such application to the called line, a pair of supervisory signals for the link circuit and means controlled over the calling line for mterrupting such application of ringing current to-the called-line and lighting sald supervisory signals for disconnection.

5. A telephone system comprising telephone lines, an operators link circuit-for 1nterconnecting said lines, means for intermittently applying ringing current to the" called line, operator controlled means for initiating the operation of said ringing means, and means controlled by either the calling or the called subscriber for disconnecting the ringing current from the called subscribers line.

6. A telephone system comprising a call-' sociating his line from the said link circuit,

and means responsive to such disassociation for interrupting the application of ringing current to the line of sa1d called subscriber;

8. A telephone system comprising a'calling and a called subscribers line, a link circuit for connecting said lines, means included in said link circuit for automaticallg applying ringing current to the said calle subscribers line, electromagnetic means responsive to a control exercised at the substation of the calling line for disassociating said calling line and said link circuit, and means controlled by said electromagnetic means for interrupting the application of ringing current to the called subscribers line.

9. A telephone system comprising telephone lines, an operators link circuit for connecting said lines, means included in said link circuit for intermittently applying ringin current to the called line, a disconnect re ay for disconnecting the calling subscribers line from the link circuit, and means controlled by said disconnect relay for interrupting the application of ringing current to said called subscribers line.

10. A telephone system comprising telephone lines, a link circuit for interconnecting said lines, means for intermittently applying ringing current to a called one of said lines, and means controlled at the substation of a calling one ofsaid lines for disassociating his line from said link circuit and for mterrupting such application of ringing current.

11. A telephone system comprising a pair of connected telephone lines, means for applying ringing current to one of said lines, means controlled at the substation of the other of said lines for disassociating said lines and for interrupting the application of ringing current to the first one of said lines.

12. A telephone system comprising a pair of connected telephone lines, means for applying ringing current to one of said lines means controlled at the substation of one 0t said lines for disassociating said lines, and means controlled at the substation of either of said lines for interrupting such application of ringing current.

13. A telephone system comprising a pair of telephone lines, an operators link circuit for connecting said lines, means included in said link circuit for applying ringing current to one of said connected lines, a disconnect relay controlled at the substation of the other of said lines for disassociatin said last line and said link circuit, and means controlled by said disconnect relay for disconnecting the ringing current from the first one of said lines.

14. A telephone s stem including a calling and a called telepll link circuit for connecting said lines in conversational circuit, means for applying ringing current and continuing such application of the same to said called line, a pair of supervisory signals for said link circuit, and means controlled by the calling subscriber for interrupting such application of ringing current to the called line and for operating both of said supervisory signals.

' 15. A telephone system including a calling subscribers line and a called subscribers line, an o erators link circuit for connecting said ines in conversational circuit, a source of ringing current, means for intermittently applying said ringing current to the said called line, an operator s switch for initiating the operation of said intermittent means, and means controlled by the callin subscriber for causing the cessation of sai intermlttent means.

16. A. telephone system including a calling subscribers telephone line and a called subone line, an opcrators All that/add link circuit connecting said lines in conversational circuit, a source of ringing current, means for intermittentl appl ing said ringing current to the cal ed su scri'bers line, operator controlled means for initiating the operation of said ringing means, and electromagnetic means controlled by the calling subscriber for preventing the intermittent application of ringing current'to the called subscribers line,

18. 'A telephone system including a calling subscribers line and a called subscribers line, an operators link circuit provided With a pair of terminals for connectmg said lines, a source of ringing current, operator controlled means tor connecting said ringing current to the said called subscribers line, a relay controlled over the calling subscribers line, and means controlled by said relay for preventing a further application of ringing current to the said called subscribers line.

19. A telephone system including a calling subscribers line and a called subscriber s line, an operators cord circuit for connecting said lines, a source of ringing current, means for intermittently applying said ringing current to the called subscribers line, operator controlled. means for initiating the operation of said applying means, and means controlled by the replacement of the receiver at the calling substation for preventing said applying means from further connecting ringing current to the called subscribers line.

20. A telephone system including a calling connection for operating said supervisor signal and for preventing the further application of said ringing current to said called subscribers line.

21. A telephone system including a calling subscribers telephone line and a called subscribers telephone line, means provided with manual terminals for connecting said lines, ringin mechanism including a relay adapted to be energized intermittently to apply ringing current to the called subscribers line,

means controlled by a central ofiice operator for associatin said mechanism With the said called subscri ers line, and automatic means controlled by the calling subscriber for disassociating said ringing mechanism from the said called subscribers line thereby preventing further intermittent applications of ringing current to the called subscribers line.

22. A telephone system including a calling subscribers telephone line and a called subscribers telephone line, an operator's link circuit for use in connecting said lines, a source of ringing current, a relay adapted to be operated intermittently to connect said ringing current to said called subscribers line, a ringing control relay controlling the operation of said first relay, means for operating said ringing control relay to initiate the operation of said first relay, and electroma netic means controlled by the calling su scriber for deenergizing said ringing control relay to prevent further operation of said first relay, thereby preventing further intermittent applications of ringing current to the said called subscribers line.

Si ed by me at Chicago, county of Cook, and tate of llllinois, in the presence 0t two witnesses.

FRED SGHOJENWOLF. Witnesses:

Gunner: 1E. MR, M. R. Roonronn.

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