US2686223A

US2686223A - Combined toll and local connector

Info

Publication number: US2686223A
Application number: US135919A
Authority: US
Inventors: Winfred T Powell
Original assignee: Stromberg Carlson Corp
Current assignee: Stromberg Carlson Corp
Priority date: 1947-02-12
Filing date: 1949-12-30
Publication date: 1954-08-10
Anticipated expiration: 1971-08-10

Description

Aug. 10, 1954 w. T. POWELL.

COMBINED TOLL AND LOCAL CONNECTOR Original F'iled Feb. 12, 1947 '7 Sheets-Sheet 1 m a N M c X E c W cm H m M 4n 0 w\ Z a N M c X 5 L w M M I I I I I I I I I I I l I I I 1w. EQKMNQQI |Vm| QBKQQQK w H M A ME QT W Y [M mm a m M m 0 1% 0 m mfl ml MM 7 U 6 F R F. E N l W w H M MM w 3 M J RX m M Hm W n i mm m 3 0 1| m 0 w r 7 A c s h M y 1 7 F OR 14. w l P 5. IP H L041 5 C X IVE/ 51975 Aug. 10, 1954 w. T. POWELL COMBINED TOLL AND LOCAL CONNECTOR Original Filed Feb. 12, 1947 7 Sheets-Sheet 2 If Ll/VE F/IVDEI? m m M r Wm w m w m P w W a. n i m m Hi 2 .W E m 7 r (Ex rppbk m E81 F? m L T m MW HT D FIAEY I w 7 F w m W/NF/RFD 7. POWELL Aug. 10, 1954 w. T. POWELL COMBINED TOLL AND LOCAL CONNECTOR 7 Sheets-Sheet 3 Original Filed Feb. 12, 194'? INVENTOR.

L H 5 w m M J m m w/ M E f E R m H M m U H a n r R 6 s a E kokumiow kwQmwQh m 4 o o $x$ek+= M w JT NB was 5 H r 1 "M w Mutts E 7 W/lVF/PED 7. POWELL XX/3am Aug. 10, 1954 w. T. POWELL COMBINED TOLL AND LOCAL CONNECTOR 7 Sheets-Sheet 4 Original Filed Feb. 12, 194'? CX REPEHTER 13 Jl l I I l 4 ||1||1 M AM Aug. 10, 1954 w. T. POWELL COMBINED TOLL AND LOCAL CONNECTOR 7 Sheets-Sheet 5 Original Filed Feb. 12, 1947 I com 5e70 17 INVENTOR. W/NF/RED Z' POWELL Aug. 10, 1954 w. T. POWELL COMBINED TOLL AND LOCAL CONNECTOR 7 Sheets-Sheet 6 Original Filed Feb. 12, 1947 wiao/vzyl JNVENTOR. W//VF/?0 Z'POWELZ Aug. 10, 1954 w. 'r. POWELL COMBINED TOLL AND LOCAL CONNECTOR Original Filed Feb. 12, 1947 TRUNK MFR/(El? 33 l 34 37 swam l I l 702/10. mm l 70 wz u/vx Patented Aug. 10, 1954 UNHTED STATES PATENT OFFICE COMBINED TOLL AND LOCAL CONNECTOR Winfred '1. Powell, Rochester, N. Y., assignor to Stromberg-Carlson Company, a corporation of New York 8 Claims.

This invention relates to multi-office telephone systems in general, but is more concerned with such systems including both automatic and manual exchanges and employing composite (CX) trunks between exchanges.

The present application is a division of my copending application Serial No. 728,004, filed February 12, 1947, and since issued as Pat. No. 2,516,645,

The invention has for its broad object the provision of new and improved circuits for effooting the toll offering and delayed toll ring in either of two automatic exchanges connected in tandem to a manual exchange.

A feature or" the invention lies in the novel toll offering arrangement, which includes a new and improved. means for controlling the toll offering operation of the connector, by way of the same above mentioned fourth dial leg, when the connector is operated from the distant manual oilice, with the toll offering feature be- .ing rendered ineiiective on local calls.

Another feature of the invention resides in the novel circuit arrangement for providing delayed toll ring, whereby the toll operator may dial the line number, seize the line, hold it and then dial the last or station digit when she is ready to complete the call.

The above and other features of the invention will be more clearly understood from a perusal of the following specification when read in connection with the accompanying drawings, comprising Figs. 1 to '7, inclusive which show by means of the usual schematic diagrams sufficient portions of a multi-omce telephone systern to enable the present invention to be understood.

Figs. 1A and 1B show a trunking layout of the telephone system, including a manual exchange and two automatic exchanges A and B. The manual exchange is indicated at the left of t: a drawing and comprises an operators cord a trunk circuit and a CX repeater cirii It will be understood that the trunk circuit and the OX repeater circuit may be combined into one unit. Repeater 253 forms the manual end of a two-way trunk extending to the first automatic exchange A, there being a plurality of such trunks.

such as I 4, as indicated. These trunks are accessible to connectors, such as is, from the 0 level. Automatic exchanges A and B are interconnected by two-way trunks terminating at exchange A in CX repeaters, such as H and terminating in line circuits selected by line finders, such as M, as indicated. The two-way trunk repeaters, such as l2, are selected for calls from exchange A to exchange B from the 8 level. These two-way trunks terminate at exchange B in OK repeaters, such as 13 and they terminate in line circuits accessible to line finders, such as [5, as indicated. These two-way trunks are selected in exchange B from the 1 level of the connectors, such as ll. Repeaters H, i2 and i3 are identical, but repeater it is of the type which functions when selected by the operator in the manual exchange instead of being selectable from a connector in an automatic exchange.

Figs. 2A and 2B disclose the circuit arrangement of the fourth dial legs between the ofiices, whereby the toll ofiering, delayed ring and alarm control functions are provided. The circuit of Figs. 2A and 2B tie in with the other circuits as indicated by the wires leading off the bottom and connecting to correspondingly identilied wires at the top of Figs. 3 and l.

Fig. 3 discloses the CX trunk or repeater circuit, such as l2 in exchange A.

Fig. 4 discloses the OK trunk or repeater circuit, such as l3 in exchange B. t will be observed that the circuits of Figs. 3 and 4 are identical, but are shown in reverse order to facilitate in the description.

Figs. 5, 6 and 7 disclose a connector circuit, such as It and I1, and a line circuit, such as the line circuit which terminates the trunk associated with repeater 53.

Referring to the trunk layout shown in Figs. 1A and 1B, a brief general description will first be given of the manner in which the various connections are established in the multi-onice system. Assuming first that the operator at the manual exchange has received a request for a connection with a subscriber in automatic exchange A. The operator inserts the calling end of the cord circuit into the jack associated with the trunk circuit extending to exchange A. When the plug of the cord is inserted in the jack, the CX repeater It operates to close a circuit over the #1 dial leg (for example) of the composite set for operating repeater H in automatic exchange A. This operation of repeater ll operates the associated incoming line circuit 3 for causing a line finder, such as M, to connect to repeater H, thus extending the connection from the operators cord circuit to connector IS.

The operator now proceeds to dial either the telephone number of a local substation in exchange A or to dial #8 for extending the connection to exchange B. Assuming first that a local station inexchange A is desired, the operation of the dial at the manual position causes repeater 18 to transmit impulses to the connector for selecting the local line. In case the called line is idle the connector I6 rings automatically and when the called subscriber answers the connector reverses the battery back to repeater ll. Responsive to this reversal of current, repeater ll conditions the #1 dial leg extending back to repeater lfl for giving answering supervision. The trunk circuit in the manual office is operated to extinguish the supervisory lamp at the operators position to inform the operator that the called partyhas answered.

At the end of the conversation, when the called subscriber hangs up the receiver, the battery connection at connector H5 is restored to normal. This causes repeater l I to condition the #1 dial leg extending back to repeater It for operating the trunk circuit to again light the supervisory lamp to show that the called subscriber has disconnected. When the operator removes the plug from the jack the trunk circuit, including repeater [0, conditions the #1 dial leg extending to repeater H and brings about the release of the connector i6 and the finder M from the line circuit associated with repeater H, thus restoring the circuits to normal.

Assume now that a subscriber in automatic exchange A desires to talk with a subscriber who can be reached only through the manual exchange. When the subscriber at the substation in exchange A lifts the receiver a line finder, such as line finder I4, is operated to extend the calling line to a connector such as connector 18. The calling party now dials the dig-its 110, Whereupon connector i6 is operated twice to the first level, being dropped back to normal after each digit #1 is dialed. Now when digit 0 is dialed, the tenth level is selected and an idle trunk extending to the manual exchange, such as the trunk associated with repeater II, is connected with the calling line. When repeater H is seized,

it transmits a calling signal by Way of the #1 dial leg which is received by repeater l9 and causes the lighting of the calling lamp associated with this trunk circuit at the operators position. Noting the lighted condition of the trunk lamp, the operator inserts the answering plug of a cord circuit into the associated jack thereby causing the trunk circuit to condition the #1 dial leg for operating a relay in repeater H which reverses the battery to the calling line to perform a metering function in case metered service is provided. The operator then completes the desired connection over the other end of the cord circuit. At the end of the conversation, when the calling party releases, repeater ll conditions the #1 dial leg for causing repeater Ill to light the supervisory lamp at the operators position. When the operator removes the plug from the trunk jack, the circuits in the manual excha ge are restored to normal.

In the event of the manual operator receiving a call for a subscriber in automatic exchange B, she inserts the plug of a cord circuit intothe jack associated with the trunk circuit and repeater l0, thereby causing the trunk circuit to condition the #1 dial leg, which in turn causes repeater II to mark this trunk circuit and to cause a line finder, such as line finder M, to connect with the marked trunk circuit, thereby extending the connection to a connector, such as connector l6. To call a subscriber in exchange 13, the manual operator dials digit 8 for selecting a trunk to exchange B, after which the number of the station in exchange B is dialed. Responsive to the operation of the dial in accordance with digit 8, the #1 dial leg of the trunk circuit extending between the manual exchange and exchange A is impulsed for stepping connector it to the eighth level. The connector automatically hunts in this level for an idle trunk extending to automatic exchange B by way of a repeater, such as 12. When repeater i2 is seized, it conditions the #1 dial leg (for example) of the two-way trunk extending between exchange A and exchange B for causing repeater 3 tomark this trunk in the line finder bank and for causing a line finder, such as line finder 5, to connect to repeater l3, thus extending the connection to connector ll. Responsive to the dialing of the remaining digits, repeater l0 transmits corresponding impulses over the #1 dial leg extending to exchange A, which are received by repeater H and retransmitted to repeater 52, whereby repeater l2 retransmits these impulses to repeater l3 in exchange B for operating connector I! to extend the connection to the wanted station. The wanted station in exchange B is signalled automatically and when the subscriber answers, the reversal of battery in connector 17 causes repeater [3 to condition the #1 dial leg extending to repeater 2 for reversing the battery to repeater ll. This reverse battery is received by repeater H which in turn conditions the #1 dial leg for causing repeater Hi to transmit an answering supervisory signal to the manual exchange cord circuit to inform the operator that the called party has answered.

At the end of the conversation, when the subscriber at the substation in exchange 13 hangs up the receiver, the battery connections from connector H to repeater I3 are restored to normal and repeater l3 transmits a disconnect signal over the #1 dial leg to repeater E2 in exchange A. Repeater i2 responds to this signal and restores the battery connections to repeater II to normal. Repeater ll responds to the battery connections being restored to normal and transmits a disconnect signal over the #1 dial leg which is received. by repeater l5 and results in the lighting of the supervisory lamp to indicate to the operator that the called party has hung up the receiver. When the operator pulls out the plug a release signal is transmitted over the #1 dial leg to repeater H in exchange A. Responsive to this impulse, repeater l i opens the loop extending through finder M and connector IE to repeater i2, causing this latter repeater to transmit a signal over the #1 dial leg to exchange B. Repeater l3 responds to this signal to open the loop extending to the link comprising line finder i5 and connector I! and thereby releases the link and restores repeater iii in exchange B to normal.

A subscriber in exchange B desiring a connection with a subscriber in exchange A prefixes #1 to the number of the wanted station. The first digit 1 causes connector ll, for example, to select repeater l3 and extend the connection by Way of repeater l2 and line finder M to con- 5, nector it. The remaining digits are effective to select the called station by way of connector it.

A subscriber in exchange A desiring a connection with a subscriber in exchange 13 prefixes #8 to the number of the wanted station. The first digit 8 causes connector it, for example, to select repeater i2 and extend the connection by way of repeater i3 and line finder E5 to connector ii. The remaining digits are effective to select the called station by way of connector ll.

it will be observed that, on a call from a subscriber in exchange B to the manual oiiice, a connector, such as connector 46 is used, thus removing such. connector from use by local lines in exchange A, and thereby reducing the trunk ing facilities for local calls in exchange A. It is possible to overcomethis condition by making repeater ii a selector repeater, with the arrow portion or" this pointing to the left going through a selector for selv the repeaters, such as repeater i I, connected to the manual exchange, instead of having this arrow connection going to the line finder terminals as shown. In this case, a connector in office A is not tied up a call from oiiice B to the manual ofice. Furthermore, in this case, level (instead of 110) would be used for calling the manual ofiice from eithe' oflice A or oflice B.

Referring to Figs. 2A and 2B the fourth dial leg of the composite set between the manual exchange an exchange A is tied in with the fourth dial of the composite set between A. and exchange this tie-in being way of relays ard not through any finder or connector link. As will be brought out in the detailed description, repeater in exchange A and any connector in exchange B can cause the common circuit of Figs. 2A and 23 to operate to provide the toll offering, delayed toll ring and alarm control functions.

Having described the trunking layout of the exchanges in general and having described generally various connections which can be established within the system, the operation of the circuits will now be explained in detail with refer ence to Figs. 2 to '7, inclusive. These figures should be laid out with 3 below Fig. 2A, with Fig. 4 below Fig. 2B and with Figs. 4, 5, 6 and 7 arranged in order to the right of Fig. 3. Since manual cord circuits, trunk circuits and repeater circuits (such as repeater it) are well known and since no particular type of these circuits is re-- quired, they ill not be shown or described, since they operate in any well known manner to cause repeater ii (not shown) and line finder i l (not shown) to repeat loop impulses to connector it for selectin repeater 82 or local lines in exchange A. Repeaters on both ends of a trunk circuit extending between exchange A and exchange 75 are shown, such repeaters i2 and it. A detailed description of the operation of th se repeaters on a call from the operator in the manual exchange by way of connector it will be described, it being assumed that repeater it operates on a loop basis for extending the connection by way of line finder it to connector it, after which connector l operates on a switch through basis when a trunk level is dialed.

For the purpose or" simplifying the drawings and facilitating the explanation, various parts and circuits have been diagrammatically shown and certain conventional illustrations have been employed. The drawings have been made more with the purpose of making it easy to understand the principles and mode of operation, than with the idea of illustrating the specific construction and arrangement of parts and circuits that would be employed in practice. Thus, the various relays andtheir contacts are illustrated in a conventional manner, the use of symbols being employed to indicate the connections to the terminals of the batteries, or other sources of current, instead of showing all of the wire connections to these terminals. Relays shown with a lower cross hatch portion are slow release, while those with an upper heavy line portion are slow operate relays. The symbols and indicate the positive and negative terminals respectively of suitable batteries or other sources of direct current and the circuits with which these symbols are used always have current flowing in the same direction, that is, from to The relay contacts have been widely separated from the relay coils, with dashed lines extending between the coils and their associated contacts, in order to simplify the drawings.

Since the present invention is more particularly concerned with busy verification, delayed toll ringing and alarm control features in a tandem network, certain circuits will be omitted from the present disclosure, with the explanation being more particularly directed to the operation from a manual exchange in connection with two automatic exchanges, connected as illustrated in Fig. 1.

Assuming that the manual operator plugs into a jack associated with the trunk circuit and 0X repeater H3 in the manual exchange, the circuits are controlled in any well known manner for conditioning CX repeater ii in automatic exchange A to cause line finder id to find line circuit associated with repeater ii for extending the connection to connector l Connector l5, which may be th same as the connector illustrated in Figs. 5, 6 and 7 may then be operated to its eighth level for selecting CZ repeater l2. From the description which follows, the operation of th relay type connector will be understood, since this connector operates in exactly the same manner as connector ll, illustrated in Figs. 5, 6 and '7.

When connector 55 selects and switches through to repeater l2, th closed circuit across the tip and ring conductors T and R of Fig. 3 operate calling bridge relay GB of repeater l2 over a circuit extending from upper winding of re lay CB, back contact of answering bridge relay AB, back contact of relay ESAP, upper winding of the left-hand portion of the repeating coil, con-- ductor T and thence through the connector line finder circuits to and it), through the closed circuit in repeater ll (not shown), back through the line finder and connector circuits (i l and t6), conductor lower wind ng of left-hand portion of the repeating coil, back contacts of relays ZSAP and AB and lower winding of relay CB to Delay CB operates closes a circuit for operating relay lSA which extends from back contact of pulse relay PL, make contact of relay CB and winding of slow-acting relay iSA to The operation of relay ISA opens up the normally energized circuit of relay ISAP, allowing this relay to release after a short tim interval. Relays CB and lSA close a circuit for energizing dial leg #1 extending from automatic exchange A to automatic exchange which circuit extends from resistance, wind ing of relay AB, make contact of relay CB, make contact of relay ISA, dial leg #1, conductor 55 extending to exchange B, dial leg #1, break contact of relay ISA of CX repeater i3, resistor and winding of relay PL to This operates relay PL, which in turn closes an obvious circuit for operating relay ZSA and this relay in turn closes an obvious circuit for operating relay ZSAP. The resistor in series with the winding of relay AB of repeater i2 is of such a value that relay AB does not operate over this circuit.

While relay ISA of repeater I2 is operated and before relay ISAP is released, a circuit is closed for operating busy verification relay 2BV of Fig. 2A, which circuit extends from (H, lower winding of relay 2BV, conductor 2|, make contact of relay ISA, make contact of relay ISAP, conductor TL, through connector is and line finder M to by Way of the resistor associated with repeater H. The operation of relay 2BV switches dial leg #4 from through the high resistance winding of alarm relay 2AM to direct through a normally closed make contact of relay 'EAMP. This circuit is opened. when relay 2BV is released by the release of relay iSAP for again energizing dial leg 3 through high resistance relay 2AM. The purpose of this pulse applied to dial leg 1 will be explained later.

Returning now to the energization of relay ZSAP of repeater I3, the line circuit relay LP, of the incoming line circuit in exchange B is operated over a circuit extending from break contact of cut-off relay C of this line circuit, make contact of relay ZSA, upper winding of the right-hand portion of the repeat coil, make contact of relay 2SAP, make contact of relay PL, upper winding of polar relay POL, make contact of relay ZSAP, lower winding of the right-hand portion of the repeat coil, make contact of relay 2SA, break contact of relay CO, and winding of relay LR to Relay LR closes its contact 29 for marking this line circuit to be found by line finder l5 (not shown), as well as closing a circuit for operating toll line relay TL which extends from make contact of relay LR, lower winding of relay TL, conductor 25, make contact of relay 3BV and resistor to Relay TL closes a locking circuit for itself by way of its upper winding which maintains this relay in its operated position until the release of the connection, this locking circuit being completed through make contacts of relays LR and CO. The circuit from to conductor 24, closed by relay BBV, is rendered efiective by the operation of relay 313V in response to the above described pulse applied to dial leg #6, this pulse extending over conductor 30 of the #2 physical circuit, break contacts of alarm relays SA and 2A and upper winding of relay 33V to When this pulse is terminated, relay 313V is released, thus operating relays 3BV and TL of the line circuit on a toll call for a purpose later to be explained. When the line finder i5 connects to the calling repeater l3, as above described, relay CO is operated over a circuit extending from make contact of relay SA of connector 5! (this relay being operated as will be later described), sleeve conductor 3S, through the line finder and winding of relay CO to Since this energization of relay PL of repeater I3 is at a compartively low value, because of the resistance in series with the relay PL, the dial leg #1 is energized at a comparatively low value for on hook supervision, this because relay AB of repeater 12 does not operate to reverse the battery back to repeater l l for repeating this supervision to the manual office.

It will now be assumed that the operator dials #2111. When connector I1 is extended to repeater l3, relay CB of the connector operates over a circuit extending from upper wind ing of relay CB, break contact of answering bridge relay AB, break contact of link cut-off relay LCO, tip conductor 5T, through the line finder I5 to the incoming line circuit, make contact of relay ZSA, upper winding of the righthand portion of the repeat coil, make contact of relay ZSAP, make contact of relay PL, upper winding of relay POL, make contact of relay ZSAP, lower Winding of the right-hand portion of the repeat coil, make contact of relay 28A, line finder l5, conductor 3R, break contacts of relays LCO and AB in series and lower winding of relay CB to Relay CB closes a circuit for operating relay SA which extends from break contact of relay LCO, make contact of relay CB and winding of relay SA to Relay SA closes a circuit for operating relay CX of the counting relay group extending from lower inner make contact of relay SA, break contact of counting release relay CRL, the stick I conductor 22, break contacts in series of counting relays C3, C2, Cl and winding of relay CX to The operator (or calling party) now receives dial tone over a circuit extending from the common dial tone conductor, make contact of relay CX, conductor DT, break contact of relay lTF, condenser 36, break contacts in series of relays AB and LCO, conductor 3T and thence over the line circuit extending to the calling station, as above described.

These counting relays operate to record the impulses of the digits dialed into the connector, but since it is not believed necessary to show all ten counting relays, in addition to the counting relay primer CX, only three of these coun ing relays are illustrated in Fig. 6. The operation of a complete bank of counting relays may be understood by reference to Powell Patent #2,241,156 where the stick i, stick 2 and

pickup conductors

22, 21 and 2B correspond to similarly identified conductors in the present disclosure.

When the first digit (#2) is transmitted, the impulses from the manual oflice operate through repeater ll, line finder l and connector :8 for intermittently opening and closing conductors T and R leading to repeater 52. This results in relay CB of repeater 12 being released. twice after which it remains energized. The first release of this CB relay opens up the above described #1 dial leg circuit, with relay lSA remaining energized during impulsing. The first release of relay CB also closes a circuit for operating change-over relay ICHO extending from break contact of relay PL, break contact of relay CB, make contact of relay ISA and winding of relay ECHO to Relay CHO short-circuits the winding of relay AB of repeater E2 to remove the impedance of this winding from the dial leg circuit so that the next energization of relay CB energizes the dial leg at a comparatively high current value. The second impulse (relay CB released) again opens up the dial leg and at the end of this impulse (relay CB operated) the #I dial leg is again energized at a comparatively high current value until relay ICHO is released, which occurs shortly after the end of the series of impulses, at which time relay AB is again inserted into the #5 dial leg.

The pulsing of the #1 dial leg effects the pulsing of relay PL of repeater it. Each release operation of relay PL opens up the above described incoming line circuit (to which connector l?! is connected) for impulsing relay CB of the con nector. The first release of relay PL closes a circuit for operating relay ECHO which extends from break contact of relay PL, break contact of relay CE, contact of relay i SA, make contact oi relay Z'SAP and winding of relay ECHO to Relay short cults the upper winding of relay POL and the right-hand repeat coil windings, so that relay PL can pulse connector if over a circuit having no impedance connects therein.

When relay PL of repeater it remains energized, after the series of impulses have been transmitted, relay ECHO is released for inserting the upper winding of relay POL and the repeat coil windings in the line circuit leading to the connector,

Referring to connector ll, the release of relay CB at the beginr ig of the first impulse closes a circuit for operating counting relay (El extending from break contact of relay LCO, break contact of relay CB, make contact of relay SA, break contact of relay conductor til, break contact of test relay TT, break contact of ringing relay RI, pick-up conductor 28, make Contact of relay GK and winding of relay Cl to Relay CX is locked operated during this pulse transmission by way of the stick 2 conductor 2.? to by way of the other break contact of relay CB and the lower inner make contact of relay SA. At the end of the first impulse (relay CB energized) stick conductor 2? is opened for releasing relay CK. opens up the dial tone circuit. When the second impulse is transmitted, the release of relay CB again applies (-1 to pick-up conductor for operating counting relay C2 by way of a contact of relay (IX and a make contact ,of relay Cl. Relay Cl i maintained energised during this pulse transmission by means of the above described circuit to the stick 2 conductor 2i, now extending through a break contact of relay GK and a make contact of relay Cl to the winding of relay Cl. At the end of this pulse transmisrelay operates and remains operated until the next digit for effecting the release of relay C l, with relay C2 being maintained in its energlued position by means of on the stick I conductor 22, by way of break contact of relay CRL and the inner lower make contact of relay SA.

t the beginning of the first impulse, relay CHO of the connector is operated, since this relay is connected to pick-up conductor 28 and at the end of the series of impulses, relay CHO is release'l, it being maintained operated during the ransinission of impulses over the above described circuit including the break contact of relay RI, as well as by means of a locking circuit for relay CHO, this latter circuit being provided to maintain relay CHO operated when relay RI is oper during pulsing, as will be later described.

"when .elay rel ases at the end of the hundreds digit transrn on, the hundreds selection is executed by means of a circuit which is to operate the selected HQ relay. In the p example, relay H62 (rig. '7) will be operbecause it was that #2 was dialed for the hundreds digit. The circuit for operating relay extends from (-l), make contact of relay SA, break contact of relay CHO, executing conductor EX, break contact or transfer relay ITF, conductor make contact of counting 1-0 relay C2, conductor H02, and winding of relay HO? to Relay HCZ closes al citing circuit for itself extending from make contact of relay SA, stick conductor STK, make contact and. winding of relay H02 to A circuit is now closed for operating relay CRL which extends from (i) on stick conductor S'EL, make contact of relay H82, conductor I-ICSTK, break contact of relay FIE and upper winding of relay CRL to The operation of relay CR1; closes a circuit for operating relay lTF which may be traced from on conductor I-ICSTK, make contact of relay CRL and winding of relay VIP to Relay lTF completes a locking circuit for itself which is independent of the make contact on relay CRL, so that relay l'IF will remain in its operated position after relay CRL is released, the release of relay CRL being effected when relay iTF operates and opens the break contact of the make before break. combination.

The operatic-11 of relay CBL opens up the stick 5 conductor 22 for effecting the release of the counting relay left operated, in this example relay C2, and when relay URL is released, conductor stick l again connected to for operating relay CX for preparing the counting relay circuits for the next digit. Transfer relay ETF well transfer relays ZTF and BTF, are slow to operate, as indicated by the heavy line section at the top of the relay coil. This is for the purpose introducing sufiicient time to release out the counting relay left operated at the end of the digit and then to operate relay CX in preparation for the next digit.

When the next (tens) digit is dialed, relay CB releases for again operating counting relay Cl and changewver relay CHO, over the previously described circuit. t the end of this impulse, relay CX i3 released, relay Cl remains operated since it assumed that this is the end of the digit, relay CHO is released for executing the tens digit. This executing circuit extends from on conductor EX (as above described), make contact of relay ITF, break contact of relay 2TB", conductor XOT, make contact of relay Cl, conductor TC! and winding of tens connector relay T'Cl Relay TC! closes a locking circuit for itself from on conductor S'I'K, make contact and winding of relay TC! to The operation of relay TCl (or any other TC relay, not shown) extends conductor STK to conductor TCSTK for again operating relay CRL over a circuit including the break contact of the make before break combination of relay 2TB. Relay CRL extends conductor TCSTK to the winding of relay ZTF for operating this relay, which in turn closes a locking circuit for itself by way of its make hefore break contact and conductor TCSTK. The op eration of relay ZTF opens up and releases relay CRL. During the interval while relay CRL was operated, relay Cl is released. Relay CK is again operated when relay CRL is released for preparing the counting relay circuits for the next digit.

When the units .digit is dialed (#1, in this example), relay GB is released once for operating relays Cl and CH0, as above described, after which relay CB remains operated for eifecting the release of relays CX and CH0. The release of relay CHO again applies to executing conductor EX for operating units connecting relay UCl over a circuit from conductor EX, make contacts of relays 1'1? and 2TF in series, break contact of relay 31 E, conductor XOU, make contact of relay C l, conductor U0! and winding of relay UCi t0 Relay UCl closes a locking circuit for itself from on conductor STK and extends this STK conductor back over conductor UCSTK, make contact of relay 2TF, break contact of relay BTF and upper winding of relay CRL to for operating this latter relay. Relay CRL extends conductor UCSTK by way of make contacts of relays ZTF, CRL, and 2TF to the winding of relay 3TF for operating this latter relay, which relay closes a locking circuit for itself by way of its make before break contact. Relay 3TH opens up and releases relay CRL and during the interval when relay CRL is operated, counting relay Cl is released and when relay CRL is released, relay CX is again operated to prepare the counting relay circuits for the station digit.

Assuming that the called line is idle the operation of relay 3TF extends the sleeve conductor 35 of the called line by way of make contacts in series of relays TC! and UCI, sleeve conductor 4S, make contact of relay BTF, break contacts in series of relays BY and lBV and make contact of relay SA to This circuit to makes the called line busy and operates its cutoff relay for removing the battery connection from the called line circuit.

In the event that the called line is busy, the connection of sleeve conductor 35 by way of conductor 48, break contact of relay 3TB, make contact of relay ZTF and lower winding of relay BY to operates relay BY before slow operating relay 3TB has time to operate after relay UCi connects the sleeve conductor of the called line to the winding of busy relay BY. The operation of relay BY closes a locking circuit for itself by way of its lower winding and its make before break contact to by way of a break contact of relay GBV and a make contact of relay SA. Relay BY opens up the winding of relay TT to prevent the operation of this relay on a call to a busy line. When the station digit is dialled relay CB applies a momentary impulse by way of its break contact, make contact of relay SA, make contact of relay BY, conductor 53, break contact of relay TL (assuming for the present that this is a call from a local line and not a toll line, in which case relay TL will be ole-energized), conductor 4e, make contact of relay 3TB, conductor 48, winding of ringing relay RI and resistor to Relay RI operates and closes a locking circuit for itself extending from on conductor STK, make contact and winding of relay RI and resistor to It will be noted that relay RI is operated over the above described circuit at the beginning of the impulse transmission, but since the pick-up conductor 28 is open at a back contact of relay RI, relay CHO is not operated and none of the counting relays are operated in response to the station digit pulses on a call to a busy line from a local line. The calling party now receives the busy tone over a circuit extending through a break contact of relay lBV, make contact of relay BY, conductor BT, make contact of relay RI, conductor 38 and small tone condenser 36 to the calling line. In a call to a busy line, sleeve conductor 48 is maintained open after relay STF is operated, since relay lBV is not operated and relay BY is operated, this for maintaining the sleeve conductor of the called line clear until the calling party hangs up and another attempt is made to connect with the called line.

Returning now to the part of the description where the called line was found to be idle, the station digit is effective to release relay CB, after which this relay remains operated. The release of relay CB closes a circuit for operating relays Cl and CH0 by way of pick-up conductor 28, as previously described. At the termination of this impulse, relays GK and CH0 are released, the latter relay closing the executing circuit from on conductor EX, make contacts of relays lTF, 2TB and 3TB in series, conductor 53, make contact of relay RI, conductor 47, break contact of relay BY, conductor 46 and winding of relay TI to The reason that relay RI is operated at this time is that its circuit is completed at the beginning of the station digit impulse transmission by way of a make contact of relay CHO, make contact of relay 3TH, conductor 33 and winding of relay RI. Relay RI closes the above described locking circuit for itself. When relay TT is operated at the end of the impulse transmission for the station digit, as above described, it closes a locking circuit for itself from on conductor EX, make contacts in series of relays ITF, ZTF and 3TB, conductor 53, make contact of relay TT, conductor 41, break contact of relay BY, conductor 48 and winding of relay TI to this locking circuit being independent of its operating circuit through the make contact of relay RI for maintaining relay TT operated after relay RI is released, as will now be described.

With relays RI and TT operated, pick-up conductor PK is extended to the winding of cut-in relay CI for operating this relay at the beginning of a ringing code transmission, as is well understood in the art. The operation of relay CI closes a locking circuit for itself including hold conductor HD for maintaining this relay operated throughout the code transmission, as is well understood in the art. 33-cycle ringing current is now applied to the called line over a circuit extending from the 33-cycle source, make contact of relay CI, make contact of relay CI, winding of trip relay TR, conductor 31, make contact of relay I-IC2, conductor 36, make contacts in series of relays RI and TT, conductor 4R, make contacts of relays UCI and TCI, called line and instrument circuits, make contacts in series of relays TC! and UCl, conductor 4T, make contacts in series of relays TT and RI, conductor 33 and make contact of relay H022 to the generator ground or return circuit for the source of ringing current. It will be noted that relay I-IC2 reverses the ringing circuit, including

conductors

33 and 33, extending to the called line, thus if #3 was the first digit dialed, then relay IICZ would not be operated and the ringing current would be applied to the called line in reverse order from that above described, thus providing for divided ringing.

When the called party answers, trip relay TR operates for short-circuiting and releasing relay RI, after which the circuit to the generator source, including relay TR, is opened for releasing this latter relay. Relay RI, in releasing, extends the called line to the windings of relay AB by way of conductors 5| and 52, this latter relay being operated to reverse the current back towards the calling station. Hold conductor HD is de-energized at the end of the code ringing cycle for releasing relay CI and the release of relay RI opens up the circuit to pick-up conductor PK so that relay CI remains de-energized throughout the remainder of the connection. Talking battery is fed to the called station through the windings of relay AB, to the calling station through the windings of relay CB, with these two stations being connected for conversation through the talking condensers and break cont etc of relay :tBV.

When the called party hangs up, relay AB releases to straighten out the battery connection giving supervision in a manner to be later ribed. When the calling party hangs up, en y CB releases for effecting the release of relay SA, after which is removed from the various conductors which maintain relays HCZ, LTF, TC 1 ZTF, UCl, called line cut-off relay, and TT operated, thus eiiecting the release of these relays and restoring the circuits to normal. The rel ase of relay SA also removes from stick conductor lSTK extending back to line finder id for releasing the line finder circuit (not shown) in a manner which is well understood in the art. Relay SA also removes from conductor 3S extending back through the line finder for releasing the cut-of. relay of the line circuit and this relay in turn opens up and releases relay thus restoring the line circuit to normal.

believed that the above example explains how the circuits function in response to the dial ing of the four digits for selectively ringing the called station for providing the various circult operations usually found in local and trunk ca It will now be explained how the repeaters in exchanges A B function to provide supern, it already having been explained how the ulsing circuits or" the repeaters function. It a 1 also be explained how the alarm and busy verification circuits operate, keeping in mind the previous circuit description.

Since, in the above explanation, it was assumed that the call came over the trunk from exchange A to exchange B and connector H was used, it will be obvious that there would be no reason for dialing #1 for the first digit on the connector because this selects the level leading to trunks back to exchange A. However, when the call is initiated in exchange A and connector i l is used, this connector will function for selecting local lines in the manner previously described. If #1 is the first digit on a local call, then when this digit is executed and is applied to conductor XOH, the circuit is extended through a make contact oi: counting relay Cl, the dotted conneciion, conductor HCi, leading to the winding of relay HCl for operating this relay. At this point will be pointed out that connector id in exchange A extends this first digit executing circuit by way of pulse absorbing conductor PA to the lower winding of relay CRL for operating this relay and since no l-IC relay is operated, relay i1? is not operated, thus efiecting the release of counting relay Ci, after which relay CRL is released for again operating relay OK to prepare the circuits for receiving the next digit. In other words, when the connector operates on a drop back basis for digit #1 (which is the case for connector it) the first digit #1 will be cancelled for absorbing digits 1 and l to allow the connector to then select level in response to dialing 116 for a call from exchange A to the manual exchange. Since connector I! in exchange B holds on level 1 for the first digit and connector is in exchange A drops back from level 1 f r the first digit, level 0 is also selected by connector for selecting a trunk to the manual exchange on a call from a local subscriber in exchange 13.

Referring back to the operation of relay H01,

on a call from a local station in exchange B, this relay closes a circuit from break contact of relay LCO, break contact of relay BY, link release conductor LORL, make contact of relay HCI, winding of marker relay ILOi, break contact of relay iLOi, break contact of common lock-out relay CLO and resistor to The operation of relay iLOl closes a locking circuit for itself including the winding of relay CLO which is effective to operate relay CLO and disconnect from the windings of all marker relays to prevent the operation of more than one of these relays in a given group at any one time.

Relay iLOl closes a circuit for operating allotter relay IALG extending from make contact of relay 1L0], break contact of guard relay GD, break contact of allotter relay iAL and winding of relay IALG to The operation of relay iALG closes an obvious circuit for operating relay GD which transfers the IALG relay circuit from its operating to its locking circuit including make contact of relay GD, break contact of relay iAL, make contact and winding of relay IALG to There is a pair of allotter relays [AL and iALCT for each trunk circuit, only one of these being shown. Since it is assumed that trunk #1 is idle, the operation of relay IALG as a result of trunk #1 being marked, completes a circuit for operating units connector relay UCl extending from make contact of relay ILOI, make contact of relay EALG and winding of relay UC! to .Relay UCl closes a locking circuit for itself extending from make contact of relay SA, conductor STK, make contact and winding of relay UCi to Since relay UCl is operated and relay 2TH is not operated, on conductor STK is extended by way of conductor UCSTK, break contact of relay ZTF and winding of relay LCO to Relay LCO operates and, at make before break contacts extends the calling line by way of

conductors

3T and 3R to conductors 5'1 and 5R, make contacts of relay UCi, make contacts of relay l-ICI, conductors lit and ER, right-hand windings of the repeat coil associated with repeater l3, break contacts in series of relays 2SAP and AB to and through the windings of relay CB for operating this latter relay.

The opperation of relay LCO of the connector opens up and releases relay CB which in turn opens up and releases relay SA. Before relay SA of the connector releases, is extended back from repeater l3 by way of conductor is and make contacts of relays HC! and UCI, conductor is, make contacts and winding of relay LCD to for locking this latter relay under the control of relay ISA of repeater l3, this latter relay being operated when relay CB of this repeater operates.

Relay LCO of the connector maintains on conductor lSTK for holding line finder it; in connection with the calling line, it extends on conductor AS back over conductor its for maintaining the cut-01f relay of the calling line operated and it applies to allotter conductor 3AL, to replace the which relay SA of the connector applied to conductor SAL for marking this connector in the allotter circuit as being in use. The line finder and associated allotter circuits have not been shown, since the line, marker, lock-out, allotter and finder circuits may be the same as shown in Figs. 2 to 4, inclusive of Powell Patent 2,325,877.

It will now be explained how the connector circuit functions to provide the delayed ring feature on a toll call, such as a call from the manual exchange to a subscriber in automatic exchange B, illustrated in Fig. 1B. Recalling that the incoming line circuit illustrated in the right-hand portion of 4 is used on a toll call and that relay TL of this line circuit has been operated and locked, when relay CX of Fig. 6 is operated when the connector is first seized, toll line relay TL of Fig. 6 is operated over a circuit extending from make contact of relay TL of Fig. 4, conductor 3TL, through the line finder l5, conductor 3TL, make contact of relay OK and winding of relay TL to At the end of the transmission of the first impulse of the first digit, relay CX releases, as above described, to open up and release relay TL. Relay TL is again operated before the second digit is dialed and is released after the first impulse of this digit, by the release of relay CX. Relay TL again operates and releases before and after the third digit is transmitted in the same manner as described for other digits. When relay CX operates to close the circuit for operating relay TL before the station digit is transmitted, a circuit is closed for operating test relay 'IT of the connector which extends from (-1-), make contact of relay SA, break contact of relay CHO, executing conductor EX, make contacts in series of relays ITF, ZTF and 3TB, conductor 53, make contact of relay TL, conductor 4?, break contact of relay BY, conductor 3G and winding of relay T to Relay TT closes the above described locking circuit for itself, thus being operated before relay RI is operated as was the case in connection with a local call previously described. With relay TT operated the ringing or station digit of the called party may be held off while the toll operator is working on the connection, thus it only being necessary for the operator to dial the last or station digit when ready to ring the called party. If a party on the called line should remove the receiver while the operator is working on the connection, the closed circuit across this line is extended by way of conductors AT and 4R, make contacts of relay TT, break contacts of relay Rl', conductors 5i and 52 and windings of relay AB to and thus operating this relay and reversing the battery connection back to the repeater for passing supervision back to the operator as an indication that someone is trying to use the line she is holding.

In the event that this supervision is not effected by a station on the called line before the operator is ready to signal the called station, the impulse or impulses transmitted to select this station efiect the operation of relay CB for closing a circuit at the first release operation of relay CB for operating relay RI. This circuit extends from (-1-) make contact of relay SA, make contact of relay CHO, make contact of relay 3TF, conductor 48, winding of relay RI and resistor to Relay RI closes the above described looking circuit for itself and, with relays RI and TT both operated, relay CI again operates to extend the ringing circuit to the called line. The circuits now function in the previously described manner for tripping the ring and for operating relay AB, with the release operation being effective to release out all operated relays in the previously described manner. It will be obvious that relay TT cannot be operated on a delayed ring toll call when the called line is busy because its winding is opened by the operation of busy relay BY.

In this event, it is necessary for the toll operator to make the busy verification test as will be later described.

Referring again to the operation on a call from the manual office to a station in automatic exchange B, when relay AB of the connector verses the battery, polar relay POL of repeater i3 is operated for short-circuiting the resistance in series with relay PL. This increases the current flow in dial leg #i to a comparatively high value for operating relay AB of repeater i2. Relay AB reverses the battery back to conductors T and R leading through connector 6 and line finder It to repeater H for operating a polar relay in this latter repeater in the same manner that relay POL of repeater i3 is operated. The polar relay in repeater i i then increases the current fiow in the dial leg leading to the manual office for operating an AB relay in this repeater or functions in any other desired manner for passing this supervisory condition back to the manual cord circuit.

When the called party hangs up, relay AB of the connector releases and straightens out the battery connection to repeater it for releasing relay POL, which again inserts the resistance in series with relay PL and dial leg #1 for releasing relay AB, this latter relay straightening out the battery connection back to repeater H, etc.

When the operator releases the connection, relay CB of repeater i2 in automatic exchange A is released for effecting the release of relay !SA. The release of relay CB opens up dial leg #i for de-energizing this conductor leading to exchange B. This effects the release of relay PL of repeater it, which in turn releases relays ZSA and ZSAP. The release of relay PL also opens up the righthand portion of the repeat coil circuit of repeater I3 for opening up the incoming line circuit and releasing the connection in exchange B. The release of relays CB of repeater i2 and repeater I3 close momentary circuits for operating the iCHO relays of these repeaters and when the ISA relays of these repeaters release, the circuit for the CH0 relays are opened and these relays release. These CHO relays perform no function at this time. The release of relay ISA of repeater [2 again closes the circuit for again operating relay [SAP thus restoring the repeater circuits to normal. Referring to Figs. 2A, 2B, 3 and 4, it will now be explained how the alarm signal is transmitted from either automatic office to the manual oifice. It is customary to provide two alarm relays, such as 1A and 2A in these automatic exchanges for operating in response to minor and major alarms. It is not believed necessary to show just how these lA and 2A relays are operated, since it is well known to those skilled in the art how much relays may be energized in response to the blowing of a fuse, the failure of an important circuit and the like, which requires the attention of an attendant. The energization of either relay iA or 2A in automatic exchang A disconnects dial leg 3 from the upper winding of relay 23V and connects this dial leg to the lower winding of relay ZBV. ihis deenergizes the normally energized #4 dial leg for effecting the release of alarm relay 5AM in the manual exchange. This in turn effects the release of repeater relay [AMP for operating slow operate relay SO and this latter relay closes a locking circuit for itself and also closes an obvious circuit for lighting the alarm lamp. This gives the operator in the manual exchange a visual indication that a case of trouble exists in either automatic exchange A orautoinatic exchange B and she can dial up special numbers in these ofiices to determine the location and the type of the trouble which exists. This dialing up circuit is not shown, since it forms no part of the present invention. When proper attention has been given to the signal, the release key may be momentarily operated for releasing relay SO, relays lAM and IAMP being restored to their normally energized conditions when the dial leg #4 is re-energized in response to the clearing of the trouble.

In the event of an alarm condition in automatic exchange B, the operation of the [A or 2A relays de-energizes the normally energized dial leg #4 extending to automatic exchange A for releasing high resistance alarm relay 2AM. Relay 2AM effects the release of relay 2AM? unless this latter relay is locked due to the operation of the busy verification feature, under which condition relay ZAMP is not released until after the busy verification momentary test is effected. The release of relay 2AMP in automatic exchange A de-energizes dial leg #4 extending to the manual exchange for bringing in the alarm lamp in the previously described manner. When the trouble condition is cleared up, dial leg #4 is again energized for operating relay 2AM, which in turn operates relay ZAMP for in turn re-energizing dial leg #4 for again operating relays IAM and IAMP, thus restoring the circuits to normal.

It will now be explained how the busy verification feature operates. From the above explanation, it will be seen that relay TL of the connector link is not operated when local calls are made through the connector. It will be assumed that a call is set up from the manual exchange to a local subscriber in automatic exchange A. Since the trunk between the manual exchange and automatic exchange A extends through repeater l I and terminates on its own line circuit, the call to the connector may be marked as coming from a toll line by simply extending by Way of a conductor corresponding to STL of Fig. 5 to connector 16. With on this conductor, relay TL will be operated in the previously described manner to mark this as a toll call. Since relay TL controls the busy verification feature and since this feature will be explained in connection with connector I? in automatic exchange B, this feature need not be explained. in connection with connector I6 because it operates in exactly the same manner in exchange A as it does in exchange B. The only difference' in the operation between a toll connection from the manual exchange to a local station in exchange A and a toll connection from the manual exchange to a local station in exchange B is that such a toll connection extending a call to the local station in exchange A is readily identified as above explained, while a toll connection through exchange A to exchange B makes use of the same interoflice trunks between exchange A and exchange B as used by local subscribers in exchange A. Consequently, it is necessary to distinguish in the connector link in exchange B between a call from a subscriber in exchange A and a call from the toll operator in the manual exchange.

When the toll operator plugs into the trunk jack, the line finder I4 extends the connection to connector 16' and the operator dials #8 for selecting a trunk to exchange B. Since-connector l6 switches-through onlevel'S' (in a manner similar to the switching through function on level 1 for connector l1, above described), the dial impulses are received by relay CB in repeater I2 (Fig. 3) connected to the interofiice trunk leading to repeater i3. Relay GB of repeater I2 repeats these impulses over dial leg #I between exchanges A and B for operating relay PL of repeater l3 in exchange B, this latter relay again repeating these impulses to relay GB of the selected connector I! in exchange B. It has been explained how the #4 dial leg of the composite set between the manual exchange and exchange A is normally energized for maintaining relay IAM in the manual exchange operated as long as there is no alarm condition set up for opening this dial leg. This normally energized circuit is also dependent on the energization of the #4 dial leg of the composite set between exchange A and exchange B. It will be understood that the opening of this #4 dial leg between exchange A and the manual exchange because of an alarm condition in exchange A or because the #4 dial leg between exchange A and exchange B is opened by an alarm condition in exchange B, de-energizes relays lAM and IAMP in the manual exchange for bringing in the alarm circuit in the previously described manner.

When the manual exchange operator selects a trunk leading to exchange B by dialing #8, the CX repeater I2 is selected. This selection effects the operation of relays CB and ISA and the release of relay ISAP of repeater l2. During the interval between the operation of relay 1 SA and the release of relay lSAP, a connection is extended from through the resistance associated with repeater l I, through line finder I l and connector l6, conductor TL, make contact of relay ISAP, make contact of relay ISA, conductor 2i and lower winding of relay 23V to This operates relay 213V, it being understood that this operation is not effected on a call from a local line in exchange A because this line does not carry the circuit from through to conductor TL of repeater l2.

The operation of relay ZBV disconnects the #4 dial leg between exchange A and exchange B from the high resistance relay 2AM and connects it to direct at a make contact of normally energized relay 2AIViP. This connection to direct operates relay SBV in exchange B over dial leg between exchanges A and B by way of the upper winding of relay SBV to Since this is only a momentary pulse on dial leg #4, relay 3BV will only be operated momentarily. At the same time that relays CB and lSA of repeater E2 in exchange A are operated, the #I dial leg is energized for operating relays PL, ZSA and ZSAP of repeater is in exchange B, all in the previously described manner. This effects the operation of line relay LR, of the incoming line circuit in exchange B for marking this line as the one to be found by line finder l5 and extends the connection to connector ll.

With line relay LR of the incoming line circuit operated at the same time that relay 3BV is operated, a circuit is closed for operating relay TL of this incoming line circuit which may be traced from make contact of relay LR, lower winding of relay TL, conductor 26, make contact of relay 33V and resistor to Relay TL locks itself operated as long as the incoming line circuit is in use, in the previously described manner. It will be understood that a call from a local line in exchange A will not operate relay 3BV, consequently relay TL of the incoming line circuit in exchange B will not be operated on such a call even though line relay LR is operated the same as if this was a toll call. Relay TL, in its operated position, marks this incoming line circuit as one coming from the manual toll board by extending over conductor 3TL to connector ll.

Referring now to connector ll, when the toll operator dials a busy line, relay BY is operated and locked, in the previously described manner. When relay 3TB operates for releasing relay CRL and again operating relay CX at the end of the units digit, relay TL is operated to on conductor 3TL. With relays BY and TL operated, busy tone is connected to the line circuit incoming to connector I! and is heard by the toll operator. With relays TL and BY operated, the operation of the dial effects the intermittent operation of relay CB, but no other relays of the connector link are operated in response to these dial impulses.

When the toll operator desires to cut in on the busy connection and offer the toll call, she operates the busy verification key BV and dials #1. The operation of key BV operates relay lBV, since a connection to is applied to key BV when any sleeve relay SL is operated. The operation of relay IBV switches dial leg #4 from high resistance relay LAM to direct for energizing this dial leg extending to exchange A, which operates relay ZBV by way of its upper winding. Relay 213V in turn switches dial leg #4 extending to exchange B from high resistance relay 2AM to direct for operating relay 313V in exchange B. Now when the one impulse is transmitted by the dial, the release of relay CB of the connector link happens at the same time that relay 3BV is operated, therefore a circuit is closed from (-1-) break contact of relay LCO of the connector, break contact of relay CB, make contact of relay SA, make contact of relay BY, conductor 43, make contact of relay TL, conductor M, upper winding of relay lBV, conductor 25, make contact of relay 3B! and resistor to This operates relay 43V and this relay in turn closes a locking circuit for itself extending from (-1-) break contact of relay LCO, make contact of relay BY, make contact and lower winding of relay lBV to The toll operator is now connected to the busy called connection by way of the talking condensers of the connector, make contacts of relay dBV, conductors QT and 4B and make contacts of relays UCi and TCI, for example, to the called line. The toll operator may ofier the call to the wanted party and if this party desires to accept the toll call the receivers on the busy connection are hung up for efiecting the release of this connection, in the previously described manner. The release of the connection removes from the called sleeve 4% of the connector used by the toll operator and this is efiective to release relay BY, since the operation of relay :lBV switched the locking circuit for relay BY from controlled by relay SA to on the called sleeve conductor.

The release of relay BY opens up the locking circuit of relay 4BV for efiecting the release of this latter relay. With relays BY and iBV released, is applied to the sleeve of the called line (48) for making this line busy and for operating the cut-off relay of this line. This circuit extends from make contact of relay SA, break contacts of the make before break combinations of relays 4BV and BY and make contact of relay 3TF to conductor 4S. This places the circuits of the connector link in condition for responding to the station digit, which is now dialed by the operator, or delayed, for operating the circuits just the same as when the station digit is dialed on a call to an idle line.

What I claim is:

1. In a telephone system comprising local and toll lines, telephone stations connected to said local and toll lines, a final connector accessible to both local and toll lines, means including dialling mechanism at said stations for establishing a connection between a calling one of said stations and said connector and for operating said connector to establish a connection between said connector and the terminals of a called line, ringing equipment operatively associated with said connector for automatically ringing the called station in response to the dialling of a station digit after said connections are established, means responsive to the establishment of a connection from a local line to said connector for preventing the completion of a talking circuit between said calling line and said called line until said station digit has been dialled, and means responsive to the establishment of a connection from a toll line to said connector for completing a talking circuit between said calling line and said called line before said station digit has been dialled.

2. In a telephone system comprising local lines and toll lines in a first ofiice and local lines in a second oiiice; telephone stations connected to said lines; a plurality of interofiice trunks connecting said ofiices; a final connector in said second office accessible to said interoffice trunks and said local lines in said second office; means including dialling mechanism at said stations on said local or said toll lines in said first office for controlling said final connector over one conductor of one of said trunks to establish a connection between said final connector and the terminals of a called line in said second ofiice; ringing equipment operatively associated with said connector and operated responsive to the dialling of a station digit after said local or said toll connection is extended to said called line for automatically ringing the called station thereon; means controlled in response to the dialling of said station digit on a connection originating on a local line in said first office for preventing the completion of a talking circuit between said calling local lines and said called line until said station digit is dialled; and means controlled over a plurality of conductors of said trunks on a connection originating on a toll line in said first ofiice for completing a talking circuit between said calling toll line and said called line before said station digit is dialled.

3. In a telephone system, a combination toll and local connector, a calling toll trunk and a calling local trunk having access to said connector, a party line accessible to said connector, means responsive to line and station selecting impulses transmitted into said connector from either of said calling trunks for directively operating said connector to extend a call to said party line and selectively signalling a party on said party line, and means responsive to seizure by said calling toll trunk only and effective before said station selecting impulses are transmitted for preparing said connector to complete a talking circuit between said calling toll trunk and said party line regardless of the busy or idle condition of said calling party line.

4. In a telephone system, a connector, a trunk line accessible to said connector, a called line, a first path over which a connection can be made to said connector by way of said trunk line, a second path over which a connection can be made to said connector by way of said trunk line, means controlled over either path for directively operating the connector to extend a connection to said called line, a relay in said connector, means effective only when the connection is established to said connector by way of said first path for operating said relay, and means including said relay for effecting a connection to said called line when it is busy.

5. In a telephone system, a connector, a trunk line accessible to said connector, 21, called party line, a irst or a second path over which a connection can be made to said connector by way of said trunk line, means controlled over either path for directively operating the connector in response to line selecting digits to extend a connection to said called party line, a signal current selecting device associated with said connector, means controlled over either path for directively operating said device in response to a station selecting digit, a relay in said connector, means efiective only when the connection is established to said connector by way of one of said paths for operating said relay, means including said relay for effecting a connection to said called line when it is busy, and means controlled by said relay for effecting or preventing a connection to said called line before said station selecting digit is dialed.

6. In a telephone system, a plurality of lines including party lines and trunk lines, an impulse transmitter associated with each of said lines, an impulse responsive connector having access to said lines, means for extending a connection from a calling one to a called one of said plurality of lines via said connector, said connector including control apparatus responsive to a series of digits transmitted thereto from one of said impulse transmitters, each digit comprising one or more impulses, said control apparatus responive to a first digit comprising a first number of impulses for determining the side of the line over which any one of said plurality of party lines is to be rung, said apparatus including a jumper which can be connected in one of a plurality of positions, means in said control apparatus responsive to impulses of a first digit comprising a second number of impulses effective when said jumper is connected in one of said positions for causing said connector to select an idle one of said trunk lines, and means in said control apparatus responsive to a first digit comprising said second number of impulses effective when said jumper is connected in another of said positions for causing said connector to drop back.

7. In a telephone system, a plurality of lines including party lines, a plurality of trunk lines, an impulse transmitter associated with each of said lines, an impulse responsive connector having access to said lines, means for extending a connection from a calling one to a called one of said pluralities of lines via said connector, said connector including control apparatus responsive to a series of digits transmitted thereto from one of said impulse transmitters, each digit comprising one or more impulses, said control apparatus including a jumper which can be connected in any one of a plurality of positions, means in said control apparatus responsive to a first digit comprising a first number of impulses for selecting the side of the line over which any one of said plurality of party lines is to be rung, other means in said control apparatus responsive to a first digit comprising a second number of impulses effective when said jumper is connected in one of said positions for causing said connector to select an idle one of said plurality of said trunk lines, and further means in said apparatus responsive to a first digit comprising said second number of impulses effective when the jumper is connected in another of said positions for causing said connector to drop back.

8. In a telephone system, a plurality of trunk lines, an impulse transmitter connected to each line, an impulse directed connector having access to said plurality of lines and including control apparatus responsive to a series of digits transmitted thereto, each digit comprising one or more impulses, means to extend a connection from a calling one of said lines to said connector, said control apparatus including a jumper which can be connected in any one of a plurality of positions, means in said apparatus responsive to a first digit comprising a first number of impulses, efiective when said jumper is connected to one of said positions for causing said connector to select an idle one of said plurality of lines, and other means in said apparatus responsive to a first digit comprising said first number of impulses effective when said jumper is connected in another of said positions for effecting a drop-back operation by said connector.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,200,829 Goodrum Oct. 10, 1916 1,227,609 Goodrum May 29, 1917 1,747,478 Lomax Feb. 18, 1930 2,332,290 Baumfalk Oct. 19, 1943 2,524,131 Molnar Oct. 3, 1950