US2186219A - Telephone system - Google Patents

Description

Jam-9, 1940. J. F. T OOMEY I 2,186,219 I "TELEPHONE SYSTEM v Filed April 28, 1958 2 Sheets-Sheet 1 I If i OPERA TORS P08! TION AND DIAL EOUIPMEN 7 CIRCUIT I TONE STRAIGHTFORWARD IN TERTOL L TRUNK C/RCU/ T lillllHl' ATTORNEY Jan. 9, 1940.

FIG. 2 TOLL smrcm/va mu/wr J. F. TOOMEY TELEPHONE SYSTEM Filed April 28, 193a 2 Sheefs-Sheet 2- /N 1/5 N TOR J l. TOOMEY 5K 1 A TTORNEV I 25 May 17 1927, the circuit of which patent shows t'oll cord supervisory lamp after it'has been eX- 25 Patents an. 5,19 v 2,186,219

NITE ATES PATENT OFFICE."

TELEPHONE SYSTEM John F. Toomey, New York,'N.- Y., assignor to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York i Application April 28, 1938, Serial No. 204,747 8 Claims. (01. 179-27) This invention relates to telephone systems and plug-ended position in which the plug ends of p more particularly to improvementsin two-way such straightforward lines terminate in a' cord straightforward, and toll switching, trunks terand plug. i

.. minating at a toll operators position. The present invention provides for the elimi- In the past when it has been desiredto' ternation of such plug-endedpositions at the -in- 5 minate two-way straightforward circuits at a I ward board and permits two-way straightforward toll board, it has been the practice to terminate intertoll trunks of the character herein dethe toll board end of the circuit in both a jack scribed to be terminated in "jacks, along with and also aicord and plug, which jack and plug other types'of "incoming lines, at the regular 10 terminals are located at difie-rent operators posi-' inward positions, while at the same time provid- 10 tions, the jack being located at a so called outing through supervision to the distant originating war board' and" the cord and plug at av sooperator on calls incoming over the straightforcalled plug-ended position of the inward ward trunks which are extended over toll switchboard. One of the "reasons for thisis that on ing trunks to called subscribers.

' inward calls for subscribers lines reachedfover' An object of the invention is to enable a toll 15 toll switching trunks, it is desirable that the operator to complete either incoming or outgoing originating or distant operator receivewhat is calls over a straightforward trunk circuit by known as thru supervision, i. e., any closure means of her regular cord circuits and,,in the or opening of the called subscribers' switchhook case of incoming calls thereover and completed contacts shall control the supervisory lamp at to a called subscribers line over a toll switching 20 the originating operators position and conversely trunk, to relay the called subscribers switchshall not affect any signal at the inward toll hook supervision through the toll cordto the operators position. Such 'an arrangement is straightforward trunk and thence to the origishown in the U. Spatent toE.R. Smith 1,629,008, nating operator without further affecting the a straightforward two-way toll line terminating tinguished by the first removal of the'receiver. at each end in both a plug and also a jack. Another object of the invention isto cause 2, Normally the jack terminations of the line at tone'signal to be transmitted back' over the each end are disconnected and the line terminates straightforward trunk to the distant end when in the plugs only. When the line is seized at the toll operator plugs one of her cord circuits 30 either end, to originate a call, the insertion of into'ajack terminating the straightforward trunk a cord circuit plug in the linejack causes the line in response to a calling signal incoming over to be connected to the jack at that end and said trunk, but to prevent the transmission of disconnected from its plug terminations. Atthe such tone signals when the operator plugs into other end of the line which still terminates in a, the same jack in the absence of a prior calling 35 plug, a line signal is displayed and when the signal. r plug end is inserted in the jack of a trunk circuit A feature of the invention whereby the first to extend the connection toa called subscriber's object is attained resides in the provision of disstation, and the suhscriber removes. his receiver criminating means in the straightforward trunk 40 from the hook, asupervisory signal is transmitted which, in cooperation with means in the toll 40 back over the line to the originatim end where switching trunk employed to extend calls to a subit lights the supervisory lamp in the opera'ters scriberis station, functionsto prevent switchhook cord circuit. Due to the fact that this is a'plugmovement at the called subscribers station subended incoming line. no cord circuit being in sequent to the subscribers answer, from affecting volved in the connection to the switching trunk, the supervisory lamp inthe cord circuit, and to 4 there is no supervisory signal at this point. relay all such switchhook supervision. including h foregoing arrangement, however sthe initial removal of the called suhscrihers resitates two different types of inward operator's ceivel, Over a; talking 1101501 0f the cord cirpositions at offices where such lines terminate, 611113 110 thasl'lraiightfmward trunk a d thence to one being of the conventional type in which lines the Originating Ope to at the distant office, 50 such as ringdown toll lines terminate in answerly W n, e 0 nn 0t 01'1 Was established in reing jacks which are adapted to be connected to sponse to a calling signal over the straightforother jack-ended circuits such as other toll lines, ward trunk and answered at the toll operators toll switching trunks, etc. by means of toll cord position.

circuits, and the other type being a so-called In other words, when the distant operator plugs 55 into the out jack of the straightforward trunk to originate a call, her cord supervisory lamp will be lighted and remain lighted until the distant calle" subscriber answers, whereupon the cord super visory lamp thereat will be extinguished and so remain until the called subscriber hangs. up, whereupon it relights, which is well-known standard toll supervision. At the inward or switching operators position when the operator, in extending the call to a subscriber reached over a switching trunk arranged in accordance with this invention, plugs into the trunk, the supervisory lamp in the cord connected to the trunk is lighted the sam as the lamp at the originating position and remains lighted until the called subscriber answers, at which time it is extinguished and remains dark thereafter and is not affected by any subsequent movement of the subscribers switchhook.

A feature whereby the second object is attained resides in other means cooperating with said discriminating means in the straightforward trunk which other means is actuated to connect a source of tone current to the straightforward trunk only when a calling signal is received over the straightforward trunk and the toll operator subsequently plugs into the straightforward trunk jack to answer.

Fig. 1 shows a standard toll operators cord circuit arranged for dialing and one end of a'twoway straightforward intertoll trunk circuit arranged in accordance with the present invention, which trunk terminates thereat in a jack; and

Fig. 2 shows an out-dial toll switching trunk.

extending from the toll operators position to an automatic exchange where it can be connected to a called subscribers line.

A description of the operation of the circuit of the invention will now be given.

Assuming a call from the distant toll oflice, incoming over the intertoll trunk of Fig. l, for a subscriber reached over the switching trunk of Fig. 2: When the distant operator inserts her plug in. the outgoing jack (not shown) of the intertoll trunk line, battery is connected in a well-known manner, to the tip of the line which operates the polarized line relay l through its upper winding to ground at the upper normal contact of relay 2. Relay l in operating operates relay 3. Relay 1. in operating operates relay i in a circuit from ground. lower contact of relay upper back contact of relay 5, and winding of relay 5 to battery. Relay 3 in operating also closes its contact H thereby completing a circuit to light the line lamp l which can be traced from battery, contact 5 of relay 9., contact in of relay contact ll of relay 3, and lamp 1 to ground. The operation of relay i closes its contacts l2, thereby connecting the lower or ring conductor is of line L through the lowerright-hand winding of repeating coil M, and a resistance 98, to the normally open contacts of relay 2, for a purpose to be hereinafter referred to.

When the ope ator notes the lighted lamp 7 she inserts the answering plug l8 of the toll cord TC in jack l5 of the line thereby comp eting a circuit to operate sleeve relay l 6 in a circuit from battery on the sleeve of the plug it, through the lower (high resistance) winding of relay it to ground. Supervisory lamp 952 in the cord does not light in this high resistance circuit. Relay 8% in operating operates relay 9. Relay 9 in operating closes its contact ll thereby completing a holding path for relay 6. Contact M of relay 9 closes a circuit to operate relay I 9 which can be traced from battery, contact 20 of relay 2|, winding and contact 22 of relay I 9, contact 23 of relay 4, contacts 24 of relay 9, contact 25 of relay 26, and contacts 2! of relay 28 to ground. Operation of relay 9 opens its contacts 8 thereby opening the previously traced circuit for line lamp 7 which is immediately extinguished.

Operation of relay l9 connects, atits contacts 29 and 3E3, the respective tip and ring line conductors 32 and I 3 to conductors 33 and 34 leading to the tone circuit at the bottom of the drawing. Relay i9 also closes its contact 35 thereby completing a locking circuit for itself from battery and contacts 20 of marginal relay 2!. Relay l9 further closes its contact 36 thereby completing a circuit to operate the tone start relay 3! in the tone circuit which can be traced ginal relay 2!, contact 36 of relay J9, and conductor 39 to ground through the upper (low resistance) and lower (high resistance) winding of relay 3'! in series. Due to the combined resistances in the two windings of relay 3?, relay 2| cannot operate at this time. Relay 31, however,

operates and closes a circuit to operate relay 26 transformer M to the line L andithence t0 the originating operator.

When relay 26 operated it closed its contacts 45 and also completed a circuit to operate slowacting relay 43 which after a short interval operates, thereby opening the previously traced circuit of interrupter Ml whereupon the tone applied to the line ceases but to be reapplied by the operation of control relay Ml which occurs, after a short interval, due to its energizing circuit being closed by the operation of relay 4-3 thereby reclosing the interrupter circuit. Operation of relay 48 operates relay 28 thereby again opening, at its contact 44, the interrupter circuit and disconnecting the application of tone to the line which impulses have now been applied twice at quickly recurring intervals. Operation of relay 28 closes its contact is thereby short-circuiting the lower and high resistance winding of relay 3?, thus lowering the resistance of the circuit previously traced for operating this relay, which circuit includes marginal relay 2!, which relay now receives sufiicient current to cause its operation. When. re ay 2! operates it closes its upper contact'thereby clos ng a short circuit around condenser 58 and at its contact 5! completes a looking circuit for itself over contacts l7 under control of relay 9. and by opening its contact 20 releases relay Hi. When relay l9 releases it disconnects the tone conductors 33 and 34 from the tip and ring of the trunk and at its contact 36 introduces a break the operating circuit for relay 3! whiclrwas opened when relay 2! cperated. This prevents a repetition of the twotone impulse when relay 2| releases at the time the plug M is removed from jack i 5.

It will now be observed that due to the fact that an incoming call was received, which the from battery, winding and contacts 38 of maroperator answered by inserting a plug in the jack,

two short impulses of tone were immediately connected to the trunk and transmitted back to the originating operator as an indication toher that the toll operator had connected to the line. If relay 4, which is only operated inresponse to an incoming signal, had not been operated, no circuit would have been prepared for the operation of relay [9 and this latter relay would not have operated to start operation of the tone circuit when the plug l8 was inserted in jack I5. Hence, it will be seen that if the intertoll trunk were seized to pass anoutgoing call by inserting plug l8 in jack l5, relay 4 would not be operated and no tone impulses would be transmitted.

Connecting to toll switching trunk We will now continue the description ofthe completion of a call. toa distant dial subscriber and which we assume is reached over the dial switching trunk' shown in Fig. 2. Upon receiving the details of the wanted subscribers number the toll operator insertsplug 52 into jack 53 of the switching trunk ST whereupon the relay 54' in the trunk operates in a circuit from battery, through the cord supervisory lamp 55, over the sleeve circuit and through the high resistance (left-hand) winding of relay 54 to ground. Operation of relay 54 closes an obvious circuit for operating relay 56 which immediately connects the right-hand low resistance winding of relay 54 in parallel with the left-hand winding thereby lowering the resistance of the sleeve circuit and permitting lamp 55 in the cord to light, it being noted that this lamp does not receive enough current to causeit to light when in series with the high resistance winding of relay 54 alone. The foregoing circuit from the right-hand winding of relay 54 can be traced from the right-hand terminal of left winding of relay 54, through the low resistance, (right-hand) winding of relay 54, contact 59 of relay 6!], contact 51 of relay 58, to ground at the outer left contact of relay 56.

Operation of relay 55 connects ground, at its.

inner left contact, to the S lead extending to the distant automatic switching equipment and also operates relay 6'! in a circuit which includes contact 68 of relay 69. t

The operator now actuates the dial key in her position circuit whereupon battery is connected to the tip of the plug 52 in a well-known manner which does not need explanation here. Battery connected to the tip of the trunk operates relay 6! through its left-hand winding over contact 62 of relay 63 and contact 64 of relay 65. Relay 6| in operating looks at its contacts 56 to ground on the C lead extending to the automatic switches, which is a well-known condition at this stage of the connection and needs no explanation. Closure of contact 66 also connects ground, from the C lead, to relay 65 which operates. Operation of relay 6| opens its contact ll) thereby removing the termination, comprising resistance H and condenser 12, from its normal connection in bridge of the trunk extending to the toll board, and at its contact 13, in series with contacts 14 of relay 65, connects the tip of the trunk from the toll office to the ring trunk conductor extending to the dial office. Closure of contact 89 similarly connects the ring conductor from the toll office through to the tip conductor leading to the dial office. I

Operation of relay 65 opens, at its contact 64, the original operating circuit for relay 6!. and

locks upover its contacts 15 and 16 toground at the inner left contacts of relay 56., The tip and ring of the trunk are now clear of all bridges and extend through to the dial oflice.

The operator now dials in the usual manner and if the called line is idle, seizure of the line by, the connector, as fully described in U. S. Patent 1,653,789,. in connection with Fig. 3 thereof, disconnects ground from the C lead thereby causing the release of relay 6| by opening the previously traced locking circuit thereof including its right-hand winding.

The release-of relay 6| reconnects ground, at

its contact I1, to the C lead which can be traced from'the inner left contacts of relay- 56, over contacts 86. of relay 69, and at its contact 19, in series with contact 14 of, relay 65, connects this same ground to the'tip conductor of thetrunk leading back to the toll board over contacts 62 of relay 63. Relay lil, in releasing also closes contacts 1.0 thereby connecting battery to the ring conductor of the trunk extending back to the toll cord. This circuit can be traced from battery, contact 15 of relay 65, resistance 8|, contact 10 of relay BI, and the lowermost contacts of relay 63.

This battery supply now furnished the dial circuit of the toll cord is in a reverse direction from that received from the dial ofiice during dialing and is also reduced in value by the series inclusion of resistance 8| and accordingly, as is well understood inthe art, causes-a polarized relay, in the dial circuit to operate-which causes the dial tobe disconnected. Further, when relay 5| releases it closes its contacts 82 thereby completing an energizing circuit for slow-operating relay 83 which can be traced from-battery, winding of relay 83, contacts 84 of relay 65 and contact 82 of relay Bl to ground at the inner leit contact of relay 56. Relay 83 operates relay 63 which is also sluggish in its operation. Relay 63 in operating connects the toll cord side of the trunk to the left-hand half of the repeating coil. 85 and Operation of relay B3 disconnects the previously applied reversed battery supply to the trunk conductors leading to the toll'cord which releases the polarized relay in the dial circuit. When the polarized. relay releases battery is connected to the tip of the trunk in a well-known manner, for a short interval which causes relay 69 to-operate in an obvious circuit. Relay 69 operated disconnects ground from the C lead by opening its contact 86 and by opening its contact 68 releases re lay 61L Relay 6''. however, in releasing closes its contact 18 thereby reconnecting ground to the C lead. During the period between the operation of relay B9 and the release of relay 61, i. e., while ground is disconnected from the C lead, a relay in the distant connector at the dial oflice is released which'initiates machine ringing to the called subscribers line in a well-known manner.

When the operator'releases the dial key thereby disconnecting the dial circuit from the cord, the conductors of the cord are connected through and now the calling trunk line L of Fig. 1 is connected through the cord to switching trunk ST and thence to the called subscribers line and the connection is ready for conversation when'the called subscriber answers. I

When the subscriber answers, marginal relay H from the right-hand low resistance winding of relay 56, thereby increasing the resistance of the sleeve circuit and extinguishing the supervisory lamp 55, and connects ground at its contacts 91 to hold relay 56 operated independent of relay 54. With relays 6t and 56 operated battery can be traced over contact 92 of relay 56 and contacts pe'ating coil 85.

93 of relay 50 to a point 94 at the mid-point of a simplex bridge, comprising resistances 95 and 95, connected across the tip and ring of the trunk at the middle of the left-hand winding of re- Battery flows back over the tip and ring conductors in parallel through the cord and incoming runk line L to the repeating coil I l where this battery, on the tip conductor 32, encounters ground through polarized relay 8? which relay now operates. Operation of relay 8'! connects ground to operate the signal relay 2 which closes its upper and lower front contacts and opens its upper back contacts, thereby substituting battery for the normal ground con- ,nected to the line and causes the cord supervisory lamp at the originating ofiice to be extin guished in a well-known manner.

Operation of relay 2 also connects battery to the ring conductor E3 of the line over the previ- H ously traced circuit including resistance 98, con- 30" to relay 56, and opens its contacts 5'! thereby interposing a break in the previously traced circuit for shunting the left-hand high resistance winding of relay 54 and preventing the sleeve re sistance being lowered-and the supervisory lamp 55 relighted when relay- 6!] releases due to the called subscriber depressing his switohhook.

When the called subscriber hangs up relay 9!! will release which in turn releases relay fill which disconnects battery. at its contact 93, from the simplex and releases polarized relay 8'! in the incoming trunk line, which in turn releases relay 2 and reconn-ects ground on the line leading back to the originating oflice where it again lights the cord supervisory lamp, all in a well-known manner. Due to the fact, however, that relay 5% is locked up to relay 56 as long as the connection remains established. supervisory lamp 55 of the toll cord is not affected for the reason that the resistance of the sleeve circuit remains high.

When the originating operator, upon noting the relighting of her supervisory lamp, and determining that the conversation is finished, disconnects from the intertoll trunk, relay l releases thereby releasing relay 3 and by reclosing its lower contacts, connects ground directly to the upper (low resistance) winding of the sleeve relay I6 thereby lowering the resistance of the previously traced sleeve circuit to a point where the cord supervisory lamp 9'! receives sufficient current to cause it to light whereuponv the toll operator removes plugs l8 and 52, from the respective jacks to which they are connected, and the circuits restore to normal.

In case the toll operator desires to extend an outgoing call to the distant toll oifice reached over the intertoll trunk L the operator will insert plu'g" l8 in jack l5 thereby operating sleeve relay IE to ground at the back contacts of relay i which relay is not operated at this time.

The circuit of relay I6 is now through its upper or low resistance winding and hence cord supervisory lamp is lighted at once. Operation of relay l6 operates relay 9 which in turn operates relay 5 in a circuit from ground, contacts ll of relay 9 and lower back contacts of relay 4. Relay 5, in operating, closes its lowermost contacts to operate relay 2 in a circuit from ground over contacts I! of relay 9 and opens its upper inner back contacts to prevent operation of relay 4 when relay 3 operates.

Relay 2 in operating substitutes battery for ground on the tip of the line L through the upper winding of polarized relay l which does not operate, however, at this time due to the direction of the current flow in the upper winding but this direction of current flow over the line lights the line lamp at the distant ofiice.

When relay 3 operates it completes, at its lower contacts, a previously prepared locking circuit for relay 5 over its inside upper contacts.

Relay 5 in operating closes its uppermost contacts to operate relay 2i which short-circuits condenser 50 for speech transmission reasons. Operation of relay 2! performs no other function at this time.

When the distant operator answers battery is connected to the tip of the line L which permits relay l to operate due to current in its lower winding, thereby increasing the resistance of the sleeve circuit and extinguishing supervisory lamp 91.

Due to the fact that relay 4 is prevented from operating by the operation of relay 5, on a call in this direction, no order tone impulses are transmitted. Further, due to the non-operation of relay 4 its contacts l2 remain open and battery is not connected to the ring conductor Hi.

What is claimed is:

1. In a telephone system, a trunk line terminating in a combined inward and outward jack, means operated in response to calling signals incoming-over said trunk, an operators cord circult adapted for connection to said trunk by way of said jack, a source of audible frequency current, means for connecting said source to trunk, and circuit means, jointly controlled by the operation of said calling signal responsive means and connection of the cord circuit to said jack, to operate said means for connecting said audible frequency current to said trunk.

2. In a telephone system, an operators position, cord circuits thereat, two-Way trunks tor-- minating in said position in combined inward and outward jacks, means associated with said trunk adapted to be operated in response to a calling signal incoming over said trunk at said position, and means jointly responsive to operation of said signal receiving means and connection or said cord circuit to said trunk jack to transmit a tone signal over said trunk.

3. In a telephone system, an operators posi tion, a trunk circuit terminating at said position in a combined inward and outward jack, cord circuits at said position adapted to be connected to said jack, a relay associated with said trunk adapted to be operated only in. response to a calling signal received over said trunk prior to connection of said cord circuit to jack, and means jointly responsive to the operated. condition of said relay and the subsequent connection of said cord circuit to the jack to transmit a plurality of momentary tone signals over said trunk. l

4. In a telephone system, a toll operators position, a two-way straightforward trunk circuit and a toll switching trunk each terminating at said position in a jack, an operators toll cord circuit for interconnecting said trunks to extend calls in either direction, a supervisory lamp associated with the cord circuit adapted to be lighted when said cord and switching trunk are connected, means for connecting the other end of said switching trunk to a called subscribers line, discriminating means in said straightforward trunk only operated in response to a calling signal in coming over said trunk, and when the straight v forward trunk jack is idle, signaling means in said straightforward trunk, effective when op'erated to transmit a supervisory signal over said straightforward trunk, means in said switching trunk, operated when the two trunks are connected and a called subscriber answers atthe distant end of said switching trunk, to extinguish said supervisory lamp and to operate said signaling means in the straightforwardtrunk over a talking conductor of said cord circuit, and other.

means in said switching trunk controlled. over another talking conductor of said cord circuit and responsive to operation of said signaling means, when said discriminating means is operated, to disable said supervisory lamp and prevent its further lighting during the remainder of the connection. I

5. In a telephone system, an operators position, a cord circuit thereat, a two-way straightforward trunk circuit terminating in a jack at said position, discriminating means associated with said straightforward trunk adapted to be,

operated only in response to a calling signal incoming over said trunk, means jointly responsive to operation of said discriminating means and connection of one end of said cord circuit to said jack to transmit a momentary tone'signal over said trunk, a toll switching trunk terminating in a second jack at said position, means at the other end of said switching trunk for extending the trunk to a subscribers line, a supervisory relay in said switching trunk responsive to removal of the called subscriber's receiver, signal transmitting means in said straightforward trunk fortransmitting a supervisory signal thereover and operated over connected talking conductors of said switching trunk, cord circuit and straightforward trunk when said discriminating means and supervisory relay are operated, a su-' pervisory lamp in the sleeve circuit of the cord connected to said switching trunk and adapted to be lighted when the cord is connected to theswitching trunk and extinguished when the supervisory relay operates, and other means in said switching trunk, controlled over other connected talking conductors of said straightforward trunk, cord circuit and switching trunk, by the joint operation of said discriminating means and signal transmitting means to disable said supervisory lamp and prevent said supervisory relay from exercising further control thereof.

- position and are *6. In a telephone system, a toll operators position, a cord circuit thereat having a supervisory signal, a two-Way straightforward intertoll trunk extending therefrom to a distant toll ofiice and a toll switching trunk extending therefrom to a distant'subscriber exchange, both of which trunks terminate"in"jacks at said toll adapted for interconnection by said cord circuit, said cord supervisory signal being adapted to be displayed when the cord is connected to the switching trunk, signal receiving means associated with said intertoll trunk adapted to operatein response to signals trans- 'mitted from the distant 'toll oflice, and means for transmitting signals over the intertoll trunk -'tosai'd distant toll office, means in said switching trunk responsive to a called subscribers answer'to retirev said cord supervisory signal and to operate said means'in the intertoll trunk for transmitting signals thereover to the distant toll office, and other means inthe switching trunk responsive to operation of said signal transmitting means in the intertoll trunk if the signal receiving means is operated to prevent further display of said cord supervisory signal.

7. In a telephone system, an operators posi tion, a two-way straightforwardand an outgoing toll switching trunkterminating thereat,

a tollcord circuit at said position for inter connecting' said trunks, a supervisory lamp in said cord adapted to be lighted when the cord is connected to the switching trunk, supervisory F relay means in the switching trunk responsive when a called subscriber, reached thereover,

answers to extinguish the cord lamp, means in the straightforward trunk actuated by operation of said supervisory relay means in the switching trunk, if the call originated over the straightforward trunk,-to cause a supervisory signal to be transmitted back over the calling straightforward trunk, and. other means in said switching trunk operated in response to transmission of said supervisory signal to prevent relighting of said cord supervisorytlamp during the remainder of the connection.

8. In a telephone system, an operators position, inward and outward trunk circuits terminating thereat, a cord circuit for interconnecting said trunks, a supervisory lamp in said cord circuit adapted to be lighted when the cord is connected to the outward trunk, supervisory relay means in the outward trunk responsive when a called subscriber, reached thereoven' the cord circuit and the outward trunk.

JOHN F. TOOMEY.

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