US2357576A

US2357576A - Pay station telephone system

Info

Publication number: US2357576A
Application number: US423758A
Authority: US
Inventors: Chester E Brooks; Erlon W Flint
Original assignee: American Telephone and Telegraph Co Inc; Bell Telephone Laboratories Inc
Current assignee: AT&T Corp
Priority date: 1941-12-20
Filing date: 1941-12-20
Publication date: 1944-09-05
Anticipated expiration: 1961-09-05

Description

Sept. 5, 1944. c, E. BROOKS Erm.L

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Patented Sept. 5, 1944 UNITED STATE s PATENT OFFICE PAY STATION 'Il'liEPHONE` SYSTEM York Application December 20, 1941, lSerial No. 423,758 e'oiaims. (C1. 17e-6.31)

This invention relates to telephone systems and more particularly to systems in which calls from `lines equipped with coin boxes are charged against the calling person through the collection of deposited coins or tokens.

In dial switching telephone systems, to enable a calling person at 'the substation of a line equipped with a coin box to establish calls, it has been the customary practice to instruct him to deposit a coin and if the call is one to be .terminated outside of the local calling area, that is, an area requiring a, toll charge, to then dial zero to secure the assistance of an A operator. In response to the extension of a connection to a trunk terminating at the ,A switchboard, an operator at that switchboard answers the call by plugging one of her cord circuits into the trunk jack, causes the coin box apparatus atthe calling substation to refund the initially deposited coin and then requests information from the calling person concerning the desired connection. The operator then makes out a tollticket and requests the calling personto deposit coins in payment for the initial period of conversation as determined by the tariff rate for a call to the desired destination. The operator after audibly hearing'the deposit of the required coins then proceeds to establish the desired connection by dialing or keying up the digits of the desired line number or through the assistance of a recording toll operator. When the called subscriber responds, if the connection is successfully established, the operator notes the time the conversation starts on the toll ticket and times the duration of the conversation. Just prior to the expiration of the initial period, the operator challenges the calling person and informs him that if he wishes to continue the conversation he should signal her when Vhe is through. When the operator receives such a termination signal she informs the calling person as to the additional coins which are required for the overtime period of conversation and listens for their deposit. When the conversation is terminated, all deposited coins are collected if the call was successful, or returned if not successful. From the foregoing brief description it will be apparent that on every toll call the operator is required to make out a toll ticket for timing the call and must give the call supervision throughout its duration. Also, some of the operators time is consumed in the establishment of the connection. Y

It is the object of the present invention to pro- -vide facilities for handling toll calls at coin box stations whereby persons using such stations may establish short haul toll connections by dialing and whereby the services of an operator to supervise such connections for the purpose of collecting and refunding deposited coins are reduced to a minimum and fewer operators are therefore required to handle such -toll tramo.

In accordance with the present invention this object is obtained bydirecting all short haul, low tariff calls from coin box lines, such as ten and -iifteen cent calls, to a trunk outgoing to a tandem office, such trunks yhaving separate appearances in the banks of district or office selectors and separate lamp and jack appearances at the A operators switchboard foreach tariff rate. On

i theinitiation of a call from a'coin box -line the calling person rst deposits a coin to enable the call to be started -and yafter receiving the usual dial tone proceeds to dial the directory number of the Wanted line. The office code and numerical digits of the line number thusV dialedare registered in the sender of the calling oflice and in accordance with the oice code digits registered, a district and, if required, an oiiice selector are set to select an idle trunk extending to a tandem office. The oice code will determine over which one of its district selectorv or office selector appearances the tandem trunk will be seized, thatis, the appearance which is allocated to the proper tariff rate for the desired connection.

Y thefA operator then plugs one of her cord circuits into the jack associated with the v'lighted lamp, whereupon the coin initially deposited is refunded and the lighted charge rate lamp is extinguished. The operator then -requests` the calling person to deposit coins in the amount indicated by the charge rate lamp which was lighted and after hearing the deposit of such coins, disconnects her cord circuit from the jack. When she disconnects her cord circuit from the jack the tandem sender is signaled to proceedy to control the completionv of the connection to the wanted line in accordance with the digit information registered therein.

When the called subscriber answers, the tming of the call -is Vinitiated and after 41/2 minutes the deposited coins areY collected. After five minutes the proper charge rate lamp Ais ashed to Vindicate to the operatorV that an overtime inter- Val has been reached. The operatoragain rplugs acord circuit into the jack associated with the -flashing lamp and directs the calling personto signal her when he is throughV talking. In most cases the subscriber will elect to terminate the Aconversation at once. If hedoesnot elect to do so, however, the operator leaves the plug of the cord circuit in the trunk jack, writes a ticket and handles the call in the manner hereinbefore described. It is thus apparent that unless the conversation extends beyond the initial period the services of the A operator are required but for a very brief interval and that upon a call in which the conversation extends beyond the initial period, which calls will constitute only about ten per cent of the short haul toll trac from coin box lines, the continued supervision of the operator will be required only during the overtime period during which the conversation is continued.

For a clearer understanding of the invention, reference may be had to the following detailed description taken in connection with the accompanying drawings, in which:

Fig. 1 shows in the upper portion thereof a coin box line terminating in a panel type oflice, a line finder, district selector, office selector and sender of which are schematically illustrated; shows in the lower portion thereof a coin box line terminating in an oflice of the well-known crossbar type, the line switch, district and oftlce selector frames, sender link switch frame, sender and marker of which are indicated by suitably labeled boxes; and shows in the right portion thereof the selector switch appearances of the outgoing end of a trunk extending from the originating oice to a tandem oflice;

E. B. Mead. The interrupters are arranged to be clutched to the shaft of the driving motor by the operation of clutch magnet 504. Interrupters 505 to 5|I, inclusive, are miscellaneous powerdriven interrupters on the interrupter frame of the originating oilice.

It will be assumed that a person at the substation |00 of the coin box line which terminates Figs. 2, 4 and 5 taken together show the outd going end of a tandem trunk;

Fig. 3 shows in the upper portion thereof the tandem oice end of the tandem trunk terminating in a, tandem district selector and in the lower portion thereof such portions of a tandem sender associable with the trunk as are necessary to an understanding of the invention; and

Fig. 6 is a chart showing how the several figures of the drawings should be arranged to completely disclose the invention.

Referring to the drawings, the apparatus of the originating panel type office X, disclosed schematically in the upper portion of Fig. 1, may be of the well-known type such as is disclosed, for example, in Patent No. 1,862,549, granted June 14, 1932, to R. Raymond and W. J. Scully,

and the apparatus of the originating crossbar';1

type office Y, disclosed schematically in the lower portion of Fig. 1, may be'of the well-known type such as is disclosed for example in Patent No. 2,093,117, granted September 14, 1937, to W. W. Carpenter. The interoice tandem trunk may be n used in common by a panel and a crossbar office if they are in the same building, by strapping both the (i0) and (c) cross connections but if such offices are not in the same building, it is to be understood that a separate group of tandem trunks would extend from each office to the tandem office, and that a trunk when outgoing from the panel office would be connected by the cross connections (p) to selector bank appearances in such office and when outgoing from the crossbar oice would be connected by the cross connections (c) to crossbar switch appearances in such office. rlhe apparatus of the tandem ofee disclosed schematically in Fig. 3 may be of the general type disclosed in Patent No. 1,840,132, granted January 5, 1932, to T. H. Roberts, the tandem sender, however, being slightly modified las will be presently described. The

interrupters

502 and 503 of Fig. 5 form a part of a motor-driven charge timer 550 of the general type disclosed in Patent No. 2,112,375, granted March 29, 1938, to

in the panel type ofce X, desiring a toll connection deposits a nickel in the nickel coin slot of the coin box apparatus |0|, and upon removing the substation receiver from the switchhook, becomes connected by a line finder |02, over the line finder-district selector trunk |03 and the usual sender link circuit (not shown) with an idle sender |04 in the manner fully described in the Patent No. 1,862,549 hereinbefore referred to. When the calling line becomes connected with the sender the usual dial tone is transmitted from the sender to apprise the calling person that he may proceed to dial the digits of the desired line number. It will further be assumed that a number is dialed, the office code digits of which indicatethat a ten cent charge is required for the initial period of conversation. In accordance with the present invention, all toll calls to be terminated in the nearby toll area, such as calls involving ten and fifteen cent initial charges, are routed over special tandem trunks to a tandem office through which they are then completed. Therefore, in response to the registration of the oflice code digits indicative of the fact that the call is to be extended into a ten cent zone of the exchange area, the sender |04 proceeds to control the setting of the district selector |05 and the office selector |06 to select an idle trunk extending to the tandem oiiice. It will be assumed that the trunk disclosed in Figs. 2 to 5, inclusive,

is idle and is therefore seized by the oflice selector |06 over the bank terminal set |01.

It will be noted that this trunk has two terminal bank appearances in the bank of office selector |06, one of which, |01, is allocated for seizure on all toll calls for which the initial charge rate is ten cents and the other of which, |08, is allocated for seizure on all toll calls for which the initial charge rate is fifteen cents. It will be obvious that if it should be desired to enable connections to be established by dial control from coin box lines to subscribers lines terminating in more remote offices of the exchange area, other appearances of the tandem trunk in banks of selector switches could be provided, allocated, for example, to calls for which the initial charge rate might be twenty cents, twenty-five cents, etc.

When the tandem trunk is seized ground is applied over the sleeve brush |00 and sleeve terminal ||0 of the trunk and thence to the sleeve terminal of all other bank appearances of the trunk and multiples thereof to mark the trunk as busy. When all dialed digits have been registered in the sender |04, a circuit is established from battery through the right winding of relay 300 and over contacts of cam 30| in the incoming end of the tandem trunk ofthe tandem office, over trunk conductor 302, the No. 8 back contact of relay 200, the No. 5 back contact of relay 20|, through the upper winding of polarized relay 202, the No. 7 back contact of relay 203, the No. 8 back contact of relay 204, conductor 205, through the upper winding of relayY I I, the No. 6 back contact of relay ||2, over the tip bank terminal of terminal set |01, tip brushes of selectors |06 and |05, contacts of cam ||3 at the district selector |05, thence through the windings of relays traced to the originating sender.

in the sender |04, returning over contacts of cam H4, ring brushes of selectors and |05, ring bank terminal of terminal set I01, the N0. 2 back contact of relay H2, conductor 206, the No. 2 back contact of relay 204, the No. 1 back contact of relay 203, through the lower winding of polarized relay 202, the No. 3 back contact of relay 20|, the No. 2 back contact of relay 200, trunk conductor 303, contacts of cam 304 to ground through the left winding of relay 300. Relays IjI and 300 operate in this circuit, relay 300 functioning to cause the association of a tandem sender with the incoming end of the tandem trunk and relay III upon operating establishing a locking circuit for itself extending from battery through the winding of relay II5, through the lower winding and contacts of relay III, conductor H6, the No, 5 normal contacts of relay 203, conductor H1, sleeve terminal H0, brush I09 to ground in the oice selector.

Relay I I5 operates in this locking circuit, locks over its upper front contact to ground on conductor H6, connects the

trunk conductors

205 and 206 over its middle upper and lower contacts to the tip and ring terminalsA of the terminal set |01 independently of the contacts of relay H2, and establishes a circuit for relay l I2 which may be traced from battery through its Winding, over the inner front contacts of relay H5 to ground. Relay H2 upon operating at its back contacts `disconnects the multiples of all unused appearances of the trunk. These operations take place while the circuits at the tandem oilice are recognizing the closure, advancing the trunk and link circuits and selecting an idle sender.

Upon the seizure of the tandem sender, a pulse receiving circuit is established between the originating sender |04 and the tandem sender, schematically disclosed in the lower portion of Fig. 3, which extends as previously traced from the sender |04 to trunk conductor 302, thence over contacts of cam 305, back contact of relay 306, upper normal contacts of relay 301', upper back contact of relay 308, serially through the windings of impulse responsive relays 309, 3I0

-and 3I I, lower back contact of relay 308, inner the end ofl the last code impulse transmitted for the units digit series, with relay 3I4 operated,

relay 308 operates in a circuit from battery through its winding, over the upper contact of relay 3I4, the lower back contact of relay 3I5,

the back contact of relay 309 to ground. With relay 308 operated the impulse receiving circuit is prepared for the reception of the final positive impulse transmitted from the sender |04 which circuit extends as previously traced over the upper normal contacts of relay 301, thence over the upper front contact of relay 308, through vthe winding of the negatively polarized impulse responsive relay 309, over the inner lower front contact of relay 308 and thence as previously Relay 308 at Iits upper back contact removes the shunt from resistance 3I6 and bridges this resistance across the impulse receiving circuit in parallel with the winding of relay 309. The winding of relay 309 is now :connected reversely -into the impulse receiving circuit whereby it is responsivel to the receipt of the inal heavy positive impulse and establishes a circuit from ground over its front contact, over the upper normal contacts of relay 3l 5, through the winding of relay 3I5 and resistance 3I1 to battery. Relay 3I1 upon operating locks over its inner upper alternate contacts to ground and prepares a circuit for relay 3I8. Upon the termination of the nal heavy positive impulse when relay 309 releases, relay 3I8 energizes in a circuit from battery through resistance 3I9, the winding of relay 3 I8, the inner upper alternate contacts of relay 3| 5 to ground. With relays 3 I 5 and 3I8 now both operated a circuit is established for transfer relay 301 extending from battery through its Winding over the lower front contact of relay 30B, the inner upper front contact of relay 3|4, the upper contacts of relays 3|5 and 3I8 to ground. With relay 301 operated, the circuit previously established by the operation of relay 3M for relay 320 is opened at the lower back contact of relay 301, relay 301 is locked over its lower front contact to ground at the lower front contact of relay 3 I4, and the circuit extending back to the originating sender is transferred from the winding of relay 300 to the windings of relays 32| and 322, trunk conductor 302 being now extended over the contacts of cam 305, the back contact of relay 306, the upper alternate contacts of relay 301, over the lower normal contacts of relay 320 to battery through the winding of relay 32| and trunk conductor 3103 being now extended over contacts of cam 3I3, the back contact of relay 3I2, the inner lower alternate contacts of relay 301, theupper normal contacts of relay 320, to ground through the winding of relay 322,.

At the outgoing end of the tandem trunk polarized relay 202 operated its armature against its left contact in response to the nal heavy positive impulse, in turn causing the operation of relay 201 in a circuitrfrcm battery through its winding and the left contact of relay 202, conductor 208 to ground at the No. 3 contact of relay H2. -Relay 201 upon operating locks in a circuit from battery through its winding over its upper contact and over the No. 1 back contact of relay 200 to ground on conductor 20B. Atthe end of the heavy positive impulse, polarized relay 202 operates its armature Vagainst its right contact thereby opening the operating circuit of relay 201 and with relay 201 locked operated, establishes a circuit from battery through the winding of relay 203, over the inner lower iront contact of relay 201 andthe right contact of relay 202 `to ground on conductor 208. Relay 201 also connects ground over the No. 2 back contact of relay 203 and its lower front contact to peg count register conductor 209 and at its back contact opens the timed release circuit. Relay 203 upon operating locks over its No. 4 contacts to ground on conductor 208; opens the peg count register circuit at its No. 2 back contact; at its No. 5 alternate contactsl establishes a new holding circuit for relay H5 extending from conductor H5 Vand conductor :l I1 to the sleeve terminals of the trunk in oiiice selectors of the panel oice; vconnects ground over its No. 3 contacts and conductor I I8 to sleeve terminals in the ofiice switches of the crossbar oilice in cases where the trunk is allocated to a crossbar oice; at its Nos. 1 and 7 back contacts opens the circuit previously traced through the windings of polarized relay 202; extends trunk conductor 205 over the No. 8 back contact of relay 204, the No. '1 front contact of relay 203, the No. 6 back Contact of relay 204 t ground through the lower winding of relay 2|3 and extends trunk conductor 206 over the No. 2 back contact of relay 204, the No. 1 front contact of relay 203, and the No. l back contact of relay 204 to battery through the upper winding of relay 2|3. Relay 20| upon operating disconnects the windings of polarized relay 202 from the

trunk conductors

302 and 303 at its Nos. 3 and back contacts, bridges at its No. 6 contacts the contacts of relay 500 included in its operating circuit; at its No. 5 front Contact connects ground over the No. 8 back contact of relay 200 and thence over the circuit traced to battery through the winding of relay 32| at the tandem sender, thereby causing the operation of relay 32| followed by the operation of relay 323, and connects ground over its No. 4 contacts, conductor 2 I 4, the No. 4 back Contact of relay 40|, conductor 402, to the armature of interrupter 501 which upon making its left Contact completes the circuit of relay 5I2 over conductor 5|3, the No. 3 back contact of relay 200, conductor 2 I 5 to battery through the winding of relay 5|2, Relay 5I2 operates in this circuit to start a timing cycle to be later described.

The operation of relay 323 at the tandem sender signals the sender that timing thereat must be suspended since there will be some delay before the A operator answers and checks the deposit of the required coins in thecoin box of the callingline. Relay 323 closes a circuit from ground over its upper front contact and the upper back contact of relay 324 to battery through the winding of relay 325. Relay 325 upon operating causes the operation of relay 326 over an obvious circuit, relay 326 upon operating, locking under the control of relay 321 over its lower front contact and the back contact of relay 321 and closingr an obvious circuit for relay 323. With relay 328 operated or unoperated, ground is connected over its'contacts, the lower normal contacts of relay 329 and the back contact of relay 325 to the back contact of timing relay 330 to start the operation of timing relays 330 to 335 to time out the tandem sender but since relay 325 has been operated this timing start circuit is not effective and the timing out of the sender is therefore delayed.

When the originating sender has completed the transmission of the nal heavy positive impulse, it advances the sequence switch of the district selector |05 into the trunk closure position and the originating sender then becomes disconnected from the line nder-district trunk |03 and is restored to normal. Relay 2|3 now operates in a circuit which may be traced from battery through its upper winding, the No. 1 back contact of relay 204, the No, 1 front con# tact of relay 203, the No. 2 back contact of relay 204, conductor 206, the middle lower front contact of relay II5, ring terminals and brushes of selectors |06 and |05, contacts of cams ||4 and I I9, ring brush of the line finder |02, thence over the calling line loop over the tip brush of line nder |02, contacts of cams |20 and ||3,

tip brushes and terminals of selectors |05 and |00, middle upper front contact of relay ||5, conductor 205, the No. 8 back contact of relay 204, the No. '1 front Contact of relay 203, the No. 6 back contact of relay 204 to ground through the winding of relay 2|3. Relay 2|3 upon operating over this circuit establishes a circuit from ground over its lower contacts, conductor 2|6, the No. 5 back contact of relay 400 to battery through the winding of slow-to-release relay 403 and at its upper contacts, prepares the circuit of relay 2|1. Relay 403 upon operating locks in a circuit extending from battery through its winding over the No. 5 back contact of relay 400, the upper front contact of relay 403, the No. 5 normal contacts of relay 40|, conductor 404, to ground at the No. '7 back contact of relay 204 and at its inner upper front Contact connects ground to conductor 405 and through the winding of relay 40| to battery. Relay 40| now operates, locking over its No. 5 alternate contacts and conductor 404 to ground at the No. 1 back contact of relay 204; opens at its No. 5 normal contacts the locking circuit for relay 403 just traced; completes the circuit of relay 2|1 which may be traced from battery through its winding over the upper contacts of relay 2|3, conductor 2|8, the No. 2 back contact of relay 406, No. l front contact of relay 40| to ground at the back contact of relay 401; opens at its No. 4 back contact the previously traced circuit for relay 5|2 which thereupon releases and at its No. 2 contacts connects the sleeve of answering jacks 2|9 and 220 over the No. 1 contacts of relay 20|, conductor 22|, No. 2 contacts of relay 40| to ground through the winding of relay 401. The circuit to the sleeves of the jacks is not closed until this time in order to prevent the operator from interfering with the call should she inadvertently connect to the trunk.

Relay 2|1 upon operating with relay ||5 operated to indicate a ten cent toll call, establishes a circuit for the lamp 224 which may be traced from battery over the contacts of'relay 2 |1, conductor 222, lower contacts of relay I |5, conductor 223, through lamp 224 to ground thereby lighting the lamp which is adjacent to jack 2|9 as a signal to the A operator that a call has been established over the trunk to which the lamp and jack appertain requiring a tollcharge of ten cents. Had the calling person dialed a called line number for which a toll charge of fifteen cents was required, the oice selector |06 would have been set to seize the trunk over the terminal set |08 thereby causing the operation of relays |2| and |25 in the same manner as relays III and I5 were operated. The circuits would then have functioned in the manner previously described except that upon the operation of relay 2|1'a circuit would have been established from battery over its contacts, conductor 222, the lower contacts of relay |25, conductor 225, to ground through the lamp 226, associated with jack 220 thereby lighting such lamp to indicate that the call has been established requiring a toll charge of fifteen cents. In order that the operator may more readily determine the amount of charge required the lamps 224 and 226 may have distinctive caps, the cap of lamp 224, for example, being red for the ten cent rate and the cap of lamp 226 being green for the fteen cent rate.

Y Initial response of an operator VInresponse to the lighted lamp 224, an operator at the A switchboard inserts the answering plug of an idle cord circuit, such as the cord circuit schematically illustrated at 221, into the jack 219 associated with the lamp 224, whereupon the circuit of relay 401 previously traced iscompleted. Relay 401 upon operating, at its inner upper contact establishes the circuit of relay 408 which operates, and opens at its back Contact the previously traced circuit of relay 211 which now releases and extinguishes the lam'p 224. Relay 228 is also operated upon the connection of a cord circuit to the jack 219 in a circuit which may be `traced in part over the tips of the cord plug and jack 219, the No. 7 back contact of relay 229, the winding of relay 228, the No. 2 back contact of relay 229 and the rings of jack 219 and the cord plug. Relay 408 upon operating connects a source of tone current associated with conductor 409 over its No. 8 contacts, conductor vv1110, the No. '1 back contact of relay 229, tips of jack 219 and cord plug to the operators cord circuit to warn the operator against starting conversation with the calling person until the connection between the calling line and the operators position has been cut through; connects the winding of relay 401 over its No. 1 contacts and conductor 411 directly to the sleeve of jack 219 and establishes a circuit for relay 412 which may be traced from battery through its winding, over conductor 413, the No. 6 back contact of relay 229, contacts of relay 228, conductor 414 to ground over its No. 6 contacts.

Relay 412 now operates, locks in a circuit extending from battery through its Winding, over conductor 413, the No. 6 back contact of relay 229, conductor '415, its No. 4 contacts to ground over the No. 6 contacts of relay 408; at its No. 2 back contact removes ground from conductor 416 extending to the line discharge network comprising resistances 230, 231 and condenser 232; at its No. 3 contacts connects resistances 514 and 515 across the calling line in bridge of the windings of relay 213 in a circuit which may be traced from battery through the upper winding of relay 213, the No. 1 back contact of relay 204, the No. 3 back contact of relay 229, conductor 233, the No. 6 back contact of relay 411, the No. 2 back contact of relay 418, the No. 3 contacts kof relay 412, conductor 419, serially through resistances 514 and 515, conductor 420, the No. 6 back contact of relay 204 to ground through the lower winding of relay 213, and connects ground over its No. 5 contacts and conductor 421 to the Xed contact of interrupter 505. As soon thereafter as the interrupter cam causes the closure of its contacts, a circuit is completed from ground connected to conductor 421, thence over conductor 422, over the inner lower normal contacts and through the winding of counting relay 423 and resistance 425 to battery and through the winding of counting relay 424 and resistance 426 to battery. Relay 423 now operates but the winding of relay 424 being shunted over its own No. 7 back contact does not operate so long as the contacts of interrupter 505 are closed. Relay 423 upon operating locks over its inner lower alternate contacts to ground over the No. 5 contacts of relay 412. Upon the 'next opening of the contacts of interrupter 505 the initial operating circuit of relay 423 is opened and relay 424 now operates in a circuit from battery through resistance 426, through its winding, over the inner lower alternate contacts of relay 423 to ground over the No. 5 contacts of relay 412. With relay 424 now operated, a shunt is established from conductor 419 over the No. 1 contacts of relay 424, and conductor 432 around resistance 515 thereby reducing the shunt across the calling line to a value of 50 ohms. With

relays

423 and 424 both operated, the circuit oi relay 500 is established from battery through its winding over conductor 516, the No. 3 contacts of relay 424, the lower contacts of relay 423 to ground at the No. 2 back contact of relay 411. lRelay 500 upon operating shunts resistance 514 over its upper contacts thereby reducing the resistance of the shunt across the calling line to zero.

Upon the next closure of the contacts associated with interrupter cam 505 ground is connected from conductor 421 over such contacts, conductor 422, the No. '1 front contact of relay 424`to a point between the winding of relay 423 and resistance 425, whereupon the winding of relay 423 becomesshunted and relay 423 releases. The circuit of relay 500 is now opened at the lower contacts of relay 423 and relay 500 releases. With relay 423 releasedy and relay 424 still operated, a circuit is established from battery through the Winding of relay 204, over conductor 234, the inner upper back contact of relay 423, the No. 6 contacts of relay 424 to ground applied to conductor 421 over the lower contacts of relay 401. Relay 204 upon operating locks over its No. 5 contacts -to ground applied to conductor 421 over the lower contacts of relay 401; disconnects the windings of relay 213 from the calling line at its Nos. 1 and 6 back contacts while the line is still short-circuited; establishes a holding circuit for relay 403 extending from battery through its winding, over the No. 5 back contact of relay 400, the No. 3 contacts of relay 401, conductor 428 to ground at the No. 7 front contact of relay 204; transfers the tip and ring trunk conductors 205 and 201i` at its Nos. 2 and 8 contacts from contacts of relay 203 to contacts of relay 229 in preparation for the return of the initially deposited coin at the coin box 101 of the calling line and establishes the operating circuit for counting relay 41.8 which may be traced from battery through resistance 429, the winding and the No. 5normal contacts of relay 418, the upper back contact of relay 423, conductor 235, the No. 3 contacts of relay 204,Y conductor 236, the No.4 contacts of relay 424 to ground at the No. 2 front contact of relay 412. The operating circuit for counting relay 411 is also prepared at this time from ground, thence as traced over the No. 5 normal contacts of relay 418 through the winding of relay 411 and resistance 430 to battery but the winding of relay 411 is shunted at this time over its own No. 7 back contact so long as relay 424 remains operated and relay 411 does not therefore operate. Relay 418 upon operating now locks over ,a circuit from battery through resistance 429, its winding and No. 5 alternate contacts, conductor 235 and thence to ground as traced.

Return of initially deposited coin With relay 418 operated coin return battery is connected from the source 511, over the No. 9 back contact of relay 518, conductor 519, lower contacts of relay 403, No. 1 back contact of relay 406, No.V 1 back contact of relay 411, No. 4 contacts of relay 418, conductor 431, over the Nos. 1 and 8 back contacts of relay 229 and the Nos. 2 and 8 front contacts of relay 204, thence as traced over the tip and ring conductors of the established connection through the magnet of coin box 101 to ground over contacts closed thereat by the deposited coin. The coin box magnet is now energized in such a manner as to deposit the coin in the return chute where it may be recovered by the calling person. Upon the second opening of the contacts associated with interrupter cam 505, the holding circuit for counting relay 424 extending from ground on conductor 42|, over the contacts of interrupter 505, conductor 422, the inner lower normal contacts of relay 423, through the Winding of relay 424 and resistance 426 to battery is opened and relay 424 releases. With relay 424 released, the shunt of the winding of relay 4|1 is removed and relay 4|1 operates over a circuit from battery through resistance 430 and its winding, over the No. 5 alternate contacts of relay 4|8, conductor 235, the No. 3 contacts of relay 204, conductor 236, the No. '1 contacts of relay 4|8, to ground at the No. 2 front contact of relay 4| 2. On the third closure of 'the contacts of interrupter 505 the previously traced circuit for relay 423 is established whereupon it reoperates but relay 424 being shunted over its own No. '1 back contact does not operate at this time. With relay 4|1 now operated the circuit over which coin return current was applied to the coin box is opened at the No. 1 back contact of relay 4|1 and the -capacity discharge of the calling line is established over the tip and ring conductors of the calling line eX- tended through the operation of relay 204 t0 the Nos. 1 and 8 back contacts of relay 229 and thence through resistances 230 and 23| and condenser 232 to ground.

Upon the third opening of the contacts of inter- A rupter 505, the shunt of the Winding of counting relay 424 is opened and relay 424 operates over the previously traced circuit. Upon the fourth closure of the contacts of interrupter 505, relay 423 is shunted down in the manner previously described and a shunt of the Winding of relay 4|8 is thereupon established from a point between its winding and resistance 429, over the No. 7 front contact of relay 4|1, the upper back contact of relay 423, conductor 235, the No. 3 contacts of relay 204, conductor 236, the No. 4 contacts of relay 424, to ground at the No. 2 front contact of relay 4 I 2. A circuit is now established from battery through the winding of relay 406 over conductor 433, the No. 6 back contact of relay 200, conductor 231, the No. 3 back contact of relay 4|8, the No. 8 conta-cts of relay 4|1 to ground over the No. 6 contacts of relay 40| whereupon relay 406 operates, locks over its No. 5 contacts to ground over the No. 6 contacts of relay 40| and establishes a circuit from battery through the winding of relay 229, over conductor 238, the No. 4 contacts of relay 406, the No. 4i contacts of relay 4|1, the upper contacts of relay 401, to ground at the No. 8 back contact of relay 400. Relay 229 upon operating locks over its No.

5 contacts, conductor 239 to ground at the inner lower front contact of relay 401; disconnects the calling line discharge -circuit at its Nos. 1 and 8 back contacts; opens the circuit over which relay 228 was energized at its No. 2 and No. 7 back contacts; opens at its No; 7 back contact the circuit over which the tone current from the tone Source 409 was applied to the cord circuit; connects the tip conductor of the calling line as traced over the No. 8 front contact of relay 204, thence over its No. 8 and No. '1 front contacts, conductor 240 and theu tips of jack 2|9 and the cord circuit plug to the tip conductor of the cord circuit and connects the ring conductor of the calling line as traced over the No. 2 front Contact Q Iilay 204,

thence over its Nos. 1 and 2 front contacts, conductor 24| and the rings of jack 220 and the cord circuit plug to the ring conductor of the cord circuit.

Uponk the fourth opening of the contacts of interrupter 505 the holding circuit of counting relay 424 is opened and relay 424 now releases in turn opening the holding circuit of relay 4|1 at its No. 4 contacts. With relay 424 released and relay 229 operated, relay 4|2 now releases and establishes a discharge path for condenser 232 through the 1600 ohm resistance 23|, over conductor 4|6 to ground at the No.' 2 back contact of relay 4|2.

Checking the deposit of coins requested for initial period With relay 229 operated the operator may now talk with the calling person and request'him to deposit the amount indicated by the lamp 224 which was previously lighted, or ten cents, to cover the initial ve-minute period of the conversation. Upon hearing the tone indicative of the deposit of the requested amount the operator disconnects her cord circuit from the jack 2|9 thereby releasing relay 401. The approximate time which has elapsed from the time the operator answered the call to operate relay 401 and the operation of relay 229 to connect her headset with the calling station is between 1.2 and 1.7 seconds. When relay 401 releases it in turn releases relays 204, 229 and 408. Relay 204 upon releasing again connects the windings of relay 2|3 to the calling line and restores supervision to the tandem trunk and relay 408 upon releasing establishes the circuit of relay 200 which may be traced from battery through its winding over conductor 242, the No. 8 contacts of relay 406, the No. '1 back contact of relay 408, conductor 2||, the inner upper back Contact of relay 500, conductor 2 I2 to ground at the No. 3 normal contacts of relay 400. Relay 200 upon operating locks over conductor 242, the No. 8 contacts of relay 406, conductor 243, its own No. 5 contacts to ground on conductor 2|2; opens the circuit of relay 20| at its No. '7 back contact whereupon relay 20| releases and over its Nos. 2 and 8 front contacts completes a talking circuit between the calling line and

outgoing conductors

302 and 303 of the tandem trunk and bridges the winding of polarized supervisory relay 244 across such outgoing trunk conductors. Relay 202 upon releasing opens at its No. 1 contacts the connection to thesleeves of trunk jacks 2|9 and 220 to prevent interference with the call should the operator plug into one of such jacks in error.

Completion of the desired connection With relay 200 operated a circuit is established from battery through the winding of relay 32| at the tandem sender, over the lower normal contacts of relayi`320, the upper alternate contacts of relay 301, the back contact of relay 306, contacts of cam 305, trunk conductor 302, the No. 8 front contact of relay 200, the winding of polarized relay 244, the No. 2 front contact of relay 200, trunk conductor 303, contacts of cam 3 I3, the back Contact of relay 3 2, the inner lower alternate contacts of relay 301, the upper normal contacts of relay 320 to ground through the winding of relay 322 at the tandem sender. The current flowing over this circuit through the winding of polarized supervisory relay 244 is in such a direction as to operate its armature against its right contact. Relays 32| and 322 at the tandem sender are now both operated in turn operating relays 323 and 324. With relay 324 operatedV the circuit of relay 325 is opened at its back contact and relay 325 releases to make the Start circuit for timing out the tandem sender operative to function in the usual manner. A circuit is also established from ground over the lower front contacts of relays 323 and 324 through thewinding of relay 321 to battery, whereupon relay 321 operates, locks in a circuit over its lower contacts, the inner upper contacts of relay 326 and the upper front contacts of relays 324 and 323 to ground. Relay 336 is also operated in a circuit from battery through its winding over the upper front contacts of relays 323 and 324 to ground and upon operating locks over its lower front contact, the lower front contact of relay 321 to ground over the lower contacts of relay 321 and the lower contacts of relay 324 and relay 323, Relay 321 upon operating opens the locking circuit of relay 326 which thereupon releases in turn opening the locking circuit of relay 321 but relay 321 isnow held operated under the control of relays 323 and 324 and relay 336 over a locking circuit extending over its lower front contacts, the lower front contacts of relay 336 to ground over the upper front contacts of relays 323 and 324. With relay 321 operated the fundamental circuit is established over its upper contacts through the winding of trunk test relay 331, contacts of

cams

338, 339 and 341 of the sender and contacts of cams 340 and 34| in the tandem district selector. The tandem sender now proceeds to complete the desired connection in accordance with the digital information registered therein in the usual manner. When the connection is completed the tandem sender is dismissed and the sequence switch of the tandem district selector is advanced to the trunk closure position in which position a circuit is established from battery through the left winding of relay 342, the upper back contact of relay 343, the upper left winding of repeating coil 344, contacts of cam 305, trunk conductor 302, the No. 8 front conta-ct of relay 200, the winding of relay 244, the No. 2 front Contact of relay 200, conductor 303, contacts of cam 3|3, the lower nleft winding of repeating coil 344, the lower back contact of relay 343 to ground through the right winding of relay 342. The direction of the current iiowiner is still in such a direction as to hold the armature of relay 244 against its right contact.

Response of the called subscriber When the called subscriber answers, a circuit is completed which may be traced in part over the contacts of cam 34|, through the upper right winding of repeating coil 344, winding of supervisory relay 345, contacts of cam 346, the lower right winding of repeating coil 344 and the upper contacts of cam 346 to cause the operation of relay 345 followed by the operation of reversing relay 343. Relay 343 upon operating reverses the connections of battery and ground through the windings of relay 342 to the

trunk conductors

302 and 303 whereby current new flows in such a direction through the winding of polarized relay 244 to cause the movement of its armature into engagement with its left contact. As soon thereafter as interrupter cam 508 closes its left contact a circuit is established from ground over the No. 4 contacts of relay 200, the left contact of relay 244, conductor 245, left contact of interrupter 508, conductor 520 to battery through the winding of relay 434 which thereupon operates and locks over its inner upper contacts to ground applied to conductor 245 by relay 244. As soon thereafter as interrupter 508 closes its right contact relay 434 establishes a circuit for relay 5|8 which may be traced from battery through its winding, over conductor 52|, the No. 5 back contact of relay 435, conductor 522, contacts closed by cam 50| of the charge timer 550, which timer is in its normal position, conductor 523, the No. 4 back contact of relay 435, the lower front contact of relay 434, conductor 524, over the right contact of cam 508 to ground on conductor 245.

' Relay 5|8 upon operating locks in a circuit eX- tending from battery through its winding, over conductor 52|, the No. 5 back contact of relay 435, conductor 522, the No.k 8 contacts of relay 5|8, conductor 525, the No. 5 back contact of relay 4|1 to ground over the No. 6 contacts of relay 406; connects ground over its No. 4 contacts to conductor 405 to hold relay 40| operated; establishes an operating circuit for relay 5|2 which maybe traced from battery through its winding, over conductor 2|5, the No. 3 front `Contact of relay 200 and conductor 246` to ground over the No. 6 contacts of relay 5|8, and starts the charge timer 550 for measuring the initial period for conversation by operating clutch magnet 504. The circuit of magnet 504 may be traced from battery through its winding, over conductor 526, the No.V 6 back contact of relay 435, conductor 521, the No. 3 contacts of relay5|8 to ground at the No'. l back contact of Yrelay 528.v

The energization of magnet 504 causes a gear train to engage with a shaft driven by a telechron motor. Four and one half minutes later acircuit is established for relay 4|2 which may be traced from battery through its winding over conductor 4|3, the No. 6 back contact of relay 220, conductor 4|5, the contacts closed by timer cam 502, to ground over the No. 2 contacts of relay 5|8. Relay 4|2 upon operating connects ground to one contact controlled by the interrupter cam 505, connects the two -ohn1 resistances 5|4 and 5|5 across the calling line and removes ground applied over conductor 4 5 from the line discharge network comprising resistances 230 and 23| and condenser 232 lin a manner described in connection with its previous operation. Under the control of interrupter 505, counting relay 423 is operated upon the rst closure of the interrupter contacts and prepares the operating circuit of counting relay 424 which thereafter operates upon the following opening of the interrupter contacts. With

relays

423 and 424 both operated resistance 5 |'5 is short-circuited thus reducing the resistance bridged across the calling lineV to 50 ohms and relay 500 is operated to shunt resistance 5|4 thus further reducing the bridged resistance to Zero. The application and reduction of the shunt across the calling line is for the purpose of diverting the current from the line prior to the connection of coin control battery thereto in order to prevent disturbances from reachingthe called subscriber through the tandem and terminating office equipment. Upon the second closure of the contacts of interrupter 505, relay 423 is released and relay 424 is locked in its operated condition. The operating circuit of relay 500 is now opened and the operating circuit of relay 204 is closed to disconnect the windings of relay 2|3 from the calling line while it is still short-circuited; to lock itself operated over conductor 421 and the'No. 6 contacts of relay 4|2, under. the control of relay 435; to transfer trunk conductors 205 a'nd206 in preparation for Lcoin collection and to establish the operating circuit of counting relay 4|8 which thereupon operates. These functions are all performed in the manner previously described.

Collection of coins deposited for initial period With relay 4|8 operated, coin collecting battery is connected from the source 529 over the No. 5 back contact of relay 528, conductor 530, the No. 3 back contact of relay 435, conductor 536, the No. 5 contacts of relay 5|8, conductor 53|, the No. 1 back contact of counting relay 4|1, the No. 4 co-ntacts of relay 4|8, conductor 43|, over the Nos. l and 8 back contacts of relay 229 and the Nos. 2 and 8 front contacts of relay 204, thence over the tip and ring conductors of the established connectie-n through the magnet of coin box to ground over contacts closed thereat by the deposited coin or coins. The coin boxmagnet is now energized in such a manner as to transfer the previously deposited coin or coins to the coin box till. Upon the second opening of the contacts associated with cam 505, relay 424 is released and relay 4|1 is operated in the manner previously described to open the circuit over which coin collecting current was applied to the coin box |0|. Upon the third closure of the contacts associated with cam 505, relay 423 again operates and with relay 4| 1 operated the capacity charge of the calling line is dissipated over the tip and ring conductors of the line extended through the operation of relay 204 to the Nos. 1 and 8 back contacts of relay 229 and thence through resistances 230 and 23| and condenser 232 to ground.

Upon the third opening of the contacts of interrupter 505, relay 424 operates and upon the fourth closure of the interrupter contacts relay 423 releases in turn releasing relay 4|8 in the manner previously described. A circuit is now established for relay 435 which may be traced from battery through its winding over conductor 431, the No. 6 front contact of relay 200, conductor 231, the No. 3 back contact of relay 4|8, the No. 8 contacts of relay 4|1 to ground over the No. 6 contacts of relay 40|. Relay 435 upon operating locks in a circuit traced throug-h its winding to conductor 231, thence over its No.2 contacts, the No. back contact of relay 408 to ground over the No. 6 contacts of relay 40|, opens the locking circuit of relay 204 at its No. 1 back contact whereupon relay 204 releases to reconnect the windings of relay 2|3 to the calling line and at its No. 5 back contact opens the locking circuit of relay 5| 8 which thereupon releases. Upon the fourth opening of the contacts of interrupter v505, relay 424 releases followed by the release of relays 4|1 and 4|2 as previously described. Relay 4|2 upon releasing discharges condenser 232 through the 160Q-ohm resistance 23|. Relay 204 has been operated for an interval of 1.2 to 1.7 seconds during the collection of the deposited coin or coins and no tone current has been transmitted to the calling line when the coins are collected to avoid encouraging the calling person to deposit further coins.

The charge timer 550 continues its operation until the normal contacts associated with its cam 50| close ve minutes after relay 5|8 operated at which time a circuit is established from battery through the winding of overtime relay 528, conductor 532, the No. 4 iront contact of relay 435, conductor 523, closed contacts associated with cam 50|, conductor 522, the No. 5 front contact of relay 435', conductor 245, the left contact of relay 244 to ground over the No. 4 contacts of relay 200 if the conversation still continues and relay 244 has therefore remained operated. Relay 528 upon operating locks over its No. 3 contacts and conductor 533 to ground over the No. 6 contacts of relay 40|; establishes a circuit from battery through the winding of relay 2|1, over the upper contacts of relay 2|3, conductor 2|8, the No. 4 contacts of relay 528, over contacts associated with interrupter cam 505, conductor 534, the No. 1 contacts of relay 40| to ground at the back contact of relay 401 whereby relay 2|1 is intermittently operated; and establishes a circuit from the sleeves of jacks 2|9 and 220 over conductor 4| the No, 2 contacts of relay 528, conductor 535, the No. 2 contacts of relay 40| to ground through the winding of relay 401. Relay 2|1 upon operating and releasing intermittently, ashes the lamp 224 ovei` the previously traced circuit as a signal to the operator that the overtime period on the established connection has been reached.

Overtime response of an operator The operator answers the hashing lamp by inserting the answering plug of one of her cord circuits into the jack 2|9 associated with such flashing lamp whereupon relay 461 operates followed by the operation of relay 228. Relay 401 upon operating opens the circuit of relay l2|1 whereby the flashing lamp 224 is extinguished and establishes the circuit of relay 408 which thereupon operates to connect the tone source on conductor 409 to the operators position to warn the operator not to commence a conversation with the calling person; opens the locking circuit of relay 435 at its No. 5 back' contact which relay thereupon releases; establishes a circuit for relay 4|2 which may be traced from battery through its Winding over conductor 4|3, the No. 6 back contact of relay 229, contacts of relay 228, conductor 4|4 to ground over the No. 6 contacts of relay 408 and closes the sleeves of jack 2|8 and 220 directly to ground through the winding of relay 401, over its No. l contacts. Relay 435 upo-n releasing reestablishes the previously traced operating circuit for relay 5|8 upon the next closure of the right contact of inter rupter 508 if the called subscriber has not disconnected and relay 4|2 upon operating locks over conductor 4|3, the No. 6 back contact of relay 229, conductor 4|5, the No. 4 contacts of relay 4|2 to ground over the No. 6 contacts of relay 408; connects the resistances 514 and 5|5 across the calling line in a circuit which may be traced from trunk conductor 205 over the No. 8 back contact of relay 204, the No. 1 front contact oi relay 203, conductor 420, through resistances 5|4 and 5|5, conductor 4|9, the No. 3 contacts of relay 4|2, the No. 2 back contact of relay 4|8, the No. 6 back contact of relay 4|1, conductor 233, the No. 3 back contact of relay 229, the No. 1 front contact of relay 203 and the No. 2 back contact of relay 284 to trunk conductor 206; at its No. 2 back contact removes ground from the line discharge network comprising resistances 230 and 23| and condenser 232 and connects ground over its No. 5 contacts and conductor 42| to one of the contacts of interrupter 505. In response to subsequent closures and openings of the contacts of interrupter 505, counting

relays

423 and 424 are operated and released in the manner previously described.

Under the control of interrupter 505 relay 423 is operated upon the first closure of the interrupter contacts and prepares` the operating circuit of relay 424 which thereafter Operates upon the following opening of the interrupter contacts.

With

relaysV

423 and 424 both operated, resistsistance to Zero. Upon the second closure of the contacts of interrupter 505, relay 423 is released and relay 424 is locked in its operated condition. The operating circuit of relay 500 is now opened and the operating circuit of relay 5204 is closed to disconnect the windings of relay 2I3 from the calling line'while it is still short-circuited; to

lock itself operated over its No. 5 contacts and conductor 421 to ground over the lower contacts of relay 401; to transfertrunk

conductors

205 and 206 to the Nos. 8 and 1 contacts of relay 229 preparatory to establishing a talking circuit with the operators cord circuit; to prepare the locking circuit of relay .403 and to establish the operating circuit of counting relay 4I8 which thereupon operates. These functions are performed in the manner previously described.

With relay 4 I 8 operated, a circuit is established from battery through the winding of relay 229 over conductor 238, the No. 4 contacts of relay 406, the No. 1 contacts of relay 4I8, the upper f contactsof relay 401 to ground at the No. 8 back contact of relay 400. Relay 229 upon operating locks over its No. 5 contacts andv conductor 239fto'ground over Vthe inner lower front contact of relay 4.01; discontinues the application oftone current from the source 409 to the operators headset;` opens the: operating circuit .of relay 4l2'leaving itr operated under the control of relay 424 and at its Nos. 1, 2, 1 and 8 front contacts cuts through a talking connection from the calling line to the' operators cord circuit. Upon the second opening of the contacts of' interrupter 505, relay 424 releases and counting relay 4I1 is operated in the manner previously described, whereupon relay 4i2 releases. relays 4I2 and 424 released, relay 4I8 releases. The calling line is now in a similar relation to the operators cord circuit as it would be on a connection established in the usual manner withy the operators position by dialing zero; the operator being able to talk with the calling person over the connection just traced over the front, contacts of relays 204 and 229, collect or return coins by the use of the collect or return keys of her position, receive supervision and control ringing. The interval from the interruption of the conversation by the operation of relay 204 until the operator is connected is from .2 to .'1 of a second. The connection between the

trunk conductors

205 and 206 and the outgoing trunk`

conductors

302 and 303 extends over front contacts of relays 204 and 229 and the outer back contacts of splitting relay 241 and thus a threeway talking connection is effected. An appreciable transmission loss is produced while the talkingikey ofthe cord circuit is operated but with this key normal the loss is negligible.

The operator upon conversing with the calling person informs him that the initial period for conversation for which he has previously deposited coins has expired. She may then follow either of two different lines of procedure dependent upon the '-traflic regulations set up by the operating company, that is, she may request;

With

the calling person to deposit the required number of coins for the overtime period if he desires to continue the conversation and make out a ticket whereby she may time the call, or she may request the calling person to signal her when he has terminated the conversation after which she will inform him as to the additional coins which he should deposit for the elapsed overtime period and she will also make out a ticket whereby she may time the call. Should she follow the first procedure and th calling party fail to deposit the required coin or coins for the overtime `period `iust beginning, she may insert a cord circuit plug into the operating jack 249'thereby establishing a circuit over the sleeves of the cord circuit plug and jack, over the No. 4 contacts of relay 229 to ground through the winding of relay 241 whereupon relay 241 operates; locks directly to the jack sleeve; at its back contacts opens the talking connection between the calling and called lines and at its outer front contacts establishes a talking connection from her cord circuit plugged into the splitting jack 249 to the talking connection extending to the called line. The operator can now talk to either the calling person or the called subscriber at will but the calling person and the called subscriber cannot talk to each other. If the calling person deposited the required coins the operator may make out a ticket, time the call and at the 'expiration of one or more overtime periods request the calling person to deposit additional coins for the additional overtime period or periods if he desires to continue the conversation. The provision of the splitting jacks enables the operator to `break in open the conversation at any time during the overtime period.` Ordinarily, she would not do so on calls for which the charge rate is more than fifteen cents because on such higher rate calls the overtime periods might be as short as one or two minutes and it would not be desirable from a service standpoint to interrupt the conversation frequently.

Should `the operator follow the second procedure, she will make out a ticket when she has ascertained that the calling person desires to continue the conversation and will .time the call. When she receives a signal from the calling person that he has terminated the conversation, she

may then inform him from the elapsed time noted on the ticket as to the amount in coins he should deposit for the overtime period or periods of conversation.

It will be obvious that the circuits could with very slight modification be arranged to automatically time each overtime period and to call in the operator at the expiration of each time period to request the deposit of an additional coin or coins for the next overtime period.

Disconnection If the calling person abandons the connection and through some trouble condition the district selector |05 or the districtjunctor of a crossbar oirlce releases without waiting for the originating sender to transmit the final heavy positive impulse to operate relay 202, relay 203 will not be operated and therefore the lockingl circuit for relay I I5 will extend as 'previously traced over conductor IIB vand the No. 5 normal contacts of relay 203 to the sleeve conductor II1. When ground is removed from the sleeve conductor I I1 at the oflice selector |06 upon its release follow'-v ing the release ofthe district selector |05, relay I I5 releases followed by the release of relay H2 thus restoring the trunk circuit to normal. The

release of apparatus at the tandem ofce follows in the usual manner.

If disconnection should occur as the district selector goes through its trunk closure position while awaiting the response of the operator initially or between the 41/2 minute interval and the beginning of the overtime interval and before relay 5|8 has operated, relay 2|3 will release. It

will be assumed that the disconnection occurs .between the 41/2 minute interval and the response of the operator. When relay 2|3 releases, relay 403 releases and a circuit is established from battery through the winding of relay 400, the No. 8 contacts of relay 40| to ground at the back contact of relay 403. Relay 400 upon operating locks over its No. 1 contacts and conductor 438 to ground over the No. 4 contacts of relay I|2; establishes a holding circuitl for relay ||5 which may be traced from conductor I I6, over the No. 5 alternate contacts of relay 203, the No. 4 back contact of relay 204, conductor 241 to ground over its No. 8 front contact; at its No. 5 back contact opens the operating circuit of relay 403 thereby locking in the disconnect condition; at its No. 3 back contact opens the locking circuit of relay 200 which thereupon releases; and establishes the circuit of relay 500 which may be traced from battery through its winding over conductor 5|6 to ground over the No. 2 contacts of relay 400. Relay 200 upon releasing opens the trunk toward the tandem district selector thereby initiating the release of the connection to the called line;

' releases relay 244 if operatedV and releases

relays

435 and 5|2. Relay 244, upon releasing, releases relay434. With relay 500 operated, a circuit is established for operating relay 204 which may be traced from battery through the Winding of relay 204 over conductor 234, the No. 4 contacts of relay 400, conductor 421 to ground over the inner upper front contact of relay 500. Relay 204, upon operating, locks directly to ground over conductor 421 and the front contacts of relay 500; opens the locking circuit of relay 40| at its No. 7 back contact; establishes a short circuit between

trunk conductors

205 and 206 over its Nos. 2 and 8 front contacts and the Nos. 1 and 8 back contacts of relay 229 toblock a trunk test on any new call and opens the locking circuit of relay ||5 at its No. 4 back contact whereupon relay ||5 releases together with relay Relay -40| upon releasing opens the holding circuit of relay 406 at its No. 6 contacts whereupon relay 406 releases and relay I5 upon releasing releases relay ||2 followed by the release of relays 203 and 400. Relay 203 upon releasing removes busy ground from the sleeve conductors ||1 and ||8 and relay 400 upon releasing releases relay 500 followed by the release of relay 204.

If a disconnection occurs before trunk closure at the district trunk |03, relays 2|3 and 403 operate on the trunk closure in the sender |04 and relay 403 locks in a circuit from battery through its winding, over the No. 5 back Contact of relay 400, over its own upper contacts, the No. 5 normal contacts of relay 40|, conductor 404 to ground over the No. 7 back contact of relay 204. When relay 40| operates following the operation of relay 403, relay 403 will release if relay 2|3 is no longer operatedA or when relay 2 |3 releases if the trunk closure has not ended. From this point the release of the trunk proceeds as just described eXcept that certain relays are not operated and need not therefore be released. The lamp 224 or 226 may flash at the A switchboard but this is held to a minimum by controlling the circuit of relay 2|1 over front contacts of both relays 2|3 and40l.

If a disconnection occurs while awaiting the initial answer of the operator, the operation is similar to that described except that relay 20| is operated thereby holding the tandem sender from releasing. When relay 400 operates as pre- Vioulsly described relay 20| is released instead of relay 200 and the tandem circuit then proceeds to release immediately.

If a disconnection occurs after relay 200 has operated but before the called subscriber has answered or on a busy back condition the operation is similar to that described except that relay 435 is not operated.

There are two disconnect conditions which may arise after relay 5|8 has operated and with no operators vcord circuit plugged into a trunk jack; one between the initial operation of relay 5|8 and the closure of the 41/2 minute contacts associated with YCam 502 of the charge timer 550, and the other after the operator has disconnected following the start of the overtime interval. This latter condition occurs only if relay 244 has operated and the operator answers at the beginning of the overtime interval. Relay 2|3 releases when the calling person disconnects, or fails t0` operate when the operator withdraws her cord circuit plug from the trunk jack 2|9 or 220. Relay 403 then releases and relay 400 operates locking over its No. 1 contacts to ground over the No. 7 contacts of relay 40| and over conductor 438 to ground over the No. 4 contacts of relay I|2; supplying a holding circuit for relay I 5; opening the operating circuit for relay 403 to lock in the disconnect condition; releasing relay 200 and operating relay 500 in the manner previously described. Relay 200 upon releasing opens the trunk toward the tandem oiiice, releases relay 244 if operated, and releases relay 5|2. With relay 244 released, relay 434 is released. Relay 500 upon operating causes the operation of relay 204 in the manner previously described whereupon the

trunk conductors

205 and 206 are connected over its Nos. 2 and 8 front contacts and the Nos. 1 and 8 back contacts of relay 229 to the line discharge network comprising resistances 230 and 23| and condenser 232; locks itself under the control of relay 500 and establishes the circuit of relay 4|2 which may be traced from battery I No. 4 front Contact of relay 204, conductor 241 to ground over the No. 8 front contact of relay 400. From this point the operation is practically the same as previously described in connection with the collection of the deposited coin for the initial period of conversation except that relay Relay H5 upon releasing releases relay |I2 and relay 40| upon releasing releases relay 406 which in turn at its No. 'l contacts removes ground from conductor 440 to release the timer if the pick-up contacts associated with cam 503 are closed. With 20|- operated followedV by ythe operation of 'relay relay f |12 Vreleased theV vtrunk circuitl releasesv to normal as previously described.

If disconnection occurswhile a cord. circuit is plugged into jack 2 9 or 220 the answering supervisory lamp at the cord circuit will be lighted; The operator then collectsthe coins remaining in the coinv box: orv if necessaryringsthe calling sta'.- tion' toobtain any money due and then withdraws the cord plug thereby releasing relay 401. Relay 401 upon releasing releases relays 204 andVY 229 and releases relay 408 if no cord. circuit has been plugged into one of the splitting'jacks 249 or 250'. Relay 2|3 will not reoperate when' relay 204 releases and the circuit will proceed to release as previously described.

Should the calling person abandon the call Without replacing the receiver on the switchhook at the calling station, the operator may release the connection when she answers the initial lighting of one of the trunk lamps 224 or 226. When vshek can obtain no response from the calling person although the receiver is still off the switchhook, a cord circuit is momentarily inserted into one of thesplittingjacks 249 or 250 thereby causing the operation of relay 241. Relay 400 is now operated at once` over a circuit which may be traced from battery through the winding of relay 400 over conductor 442, the No. 2 contacts of relay 20| to ground over the inner upper contacts of relay 241 andlupon operating releases relay 20| and the tandem oilice circuits. When the.

operator withdraws the cord circuit, from the answering jack the circuit releases' as on a regular disconnection before the operator answers except that relay 20| is already released.

Timed release 5| I, the inner lower contacts of relay 5|2, con

ductor 539 the right contact of relay 244 to ground over theNo. l contacts of relay 200; locks over its lower-contacts to its operating circuit independent of thecontacts of interrupter 5| and closes a circuit from battery through the winding of relay 540, over its upper contacts* as soon as the contacts associated with interrupter cam 5 I 0 close. With relays 5|2 and 540 both operated a circuit is established from ground over contacts of relay 540, the middle lower contacts of relay 5|2, conductor 54|, the lower back contact of relay 201, conductor 44|, the back contacts of relay .434 to battery through the winding of relayv 400. The trunk then proceeds to release in the manner previously described except that if a cord cir'-y cuit has been plugged into one of the jacks 2|9 or 220, only the tandem ollice equipment is released immediately. In this case when the operator withdraws the cord plug, relay 403 is already released and relaysr400, 500 and 203 are operated. It is to be noted that the interrupters 5|0Y and 5|| and relays 538 and 540 constitute a timed release control equipment common to live trunks.

Trunk closure fuz'Zure It wiu be recaued that at the 'end of the transmission of the final heavy positive impulse, relay 5|2 as soon thereafter 'as interrupter cam 501 closesV its left contact. `WithV relay 5|2 operated,

iftrunk closure is not completed by the time cam' Time alarm circuit The time alarm circuit comprisingr the interrupter cam 509, relays 544 and 545, lamp 546 andV key 541 is provided for each group of ve trunks. Whenever either relay 400 or 4|2 operates with relay 408 released a timing cycle is started' in order to check that the circuit can release and control coins properly. The circuit for starting theV timing cycle may be traced from battery throughv thewinding of relay 543, over conductor 548, the No. 4 back contact of relay 408, over the No. 1 front contact of relay 4I2 or the No. 6 front contact of. relay 400, conductor 549, the upper normal contacts of relay 543, the back contact of relay 544 to ground over the back contact of relay 545. Relay 543, which is individual to the trunk, upon operating locks itself over its upper alternate contacts independent of relays 544 and.

545 and establishes a circuit from ground over its inner contacts and the right contact of inter- Relay 545 upon operatinglocks under the control' of alarm release key 541, establishes an alarm circuit over its inner lower front contact, lights the alarm lamp 546 and opens a further point in theoperating circuits of relay 543 and similar relays.

In some exchange areas the initial deposit of a coin to `initiate the starting of a call is not re-' quired, but the completion of the connection isH arrested, for example, just prior to the units selection operation of the nal selector, until the callingr subscriber has deposited a coin. With this mode of procedure a calling subscriber may make emergency calls to an operator even though hehas no coin of the suitable denomination forv depositin the coin box. They trunk circuit of the present invention will function equally well in exchange areas of this character.

What is claimed is: f 1. In atelephone system, a rst oilice, a coin' box'- line terminating' therein, a tandem oilice, terminating offices, switching mechanism in said oces, control means in said tandemollce, an

operators position having cord circuits in said first olhce,x a trunk extendingbetween said firstv and said tandem oilices having a separate appearance in the switching mechanism of said first ofce and a corresponding` lampand jack appearance' at said operators position for each of a plurality of charge rates for calls from said line to desired lines terminating in said terminating oices, means operated upon the seizure of said trunk to prepare said control means for controlling the completion of the desired connection and for lighting the lamp at said operators position indicative of the charge rate for the desired connection, means operative following the connection of a cord circuit of said position to the jack associated with the lighted lamp for enabling the operator to request and to checkthe deposit of the required coin or coins, and means responsive to the disconnection of said cord circuit from said jack for signaling said control means to proceed with the control of the completion of the desired connection.

2. In a telephone system, a iirst oilice, a coin box line terminating therein, a tandem office, terminating 'orlices, switching mechanism in said oices, control means in said tandem oice, an operators position having cord circuits in said iirsl-l omce, a trunk extending between said first and said tandem oices having a separate appearance in the switching mechanism of said rst oice and a corresponding lamp and jack appearance at said operators position for each of a plurality of charge rates for calls from said linefto desired lines terminating in said terminating oflices, means operated upon the seizure of said trunk to prepare said control means for controlling the completion of the desired connection and for lighting the lamp of said operators position indicative of the charge rate for the desired connection, means operative in response to the connection of a cord circuit of said position to the jack associated with the lighted lamp for refunding the coin initially deposited in the coin box of said calling line, means thereafter effective to enable the operator to request and to check the deposit of a coin or coins in payment for the initial period of conversation, and means responsive to the disconnection of said cord circuit from said jackY for signaling said control means to proceed with the control of the completion of the desired connection. i

3. In a telephonel system, a rst oice, a coin box line terminating therein, a tandem office, terminating offices, switching mechanism in said oiiices, control means in said tandem office, an operators position having cord circuits in said first oflice, a trunk extending between said rst and said tandem offices having a separate appearance in the switching mechanism of said iirst oiiice and a corresponding lamp and jack appearance at said operators position for each of a plurality of charge rates for calls from said line to desired lines terminating in said terminating offices, means operated upon the seizure of said trunk to prepare said control means for controlling the completion of the desired connection and for lighting the lamp at said operators position indicative of the charge rate for the desired connection, means operative in response to the connection of a cord circuit of said position to the jack associated with the lighted lamp for refunding the coin initially deposited, means effective a measured interval thereafter for discharging the capacity charge from said cord circuit from said jack for signaling said" control means to proceed with the control of theV terminating offices, switching mechanism in said ofces, control means in said tandem office, an operators position having cord circuits in said iirst oice, a trunk extending between said first and said tandem offices having a separate appearance in the switching mechanism of said rst oice and a corresponding lamp and jack appearance at said operators position for each of a plurality of charge rates for calls from said line to desired lines terminatingl in terminating orlices, means operated upon the seizure of said trunk to'prepare said control means for controlling the completion of the desired connection and for lighting the lamp at said operators position indicative of the charge rate for the desired connection, means operative following the connection of a cord circuit of said position to the jack associated with the lighted lamp for enabling the operator to request and to check the deposit of a coin or coins in payment'for the initial period of conversation, means responsive to the disconnection of said cord circuit from said jack for signaling said control means to proceed with the control of the completion of the desired connection, and means operative a predetermined interval following the response of the called subscriber for causing the collection of the deposited coin or coins.

5. In a telephone system, a first olice, a coin box line terminating therein, a tandem office,

terminating offices, switching mechanism in said offices, control means in said tandem ofce, an operators position having cord circuits in said rst omce, a trunk extending between said rst and said tandem oflices having an appearance in the switching mechanism of said first oice and a lamp and jack appearance at said operators position for each of a plurality of charge rates for calls from said line to desired lines terminating in said terminating offices, means operated upon the seizure of said trunk to prepare said control means for controlling the completion of the desired connection and for lighting the lamp at said operators position indicative of the charge rate for the desired connection, means operative in response to the connection of a cord circuit of said position to the jack associated with the lighted lamp for refunding the coin initially deposited in the coin box of said calling line, means thereafter ellective to enable the op- .erator to request and to check the deposit of a coin or coins in payment for the initial period of conversation, means responsive tothe disconnection of said cord circuit from said jack for signaling said control means to proceed with the control of the completion of the desired connection, and means operative a predetermined interval following the response of the called subscriber for causing the collection of the last deposited coin or coins.

6. In a telephone system, a rst oflice, a coin box line terminating therein, a tandem oilice, terminating oiices, switching mechanism. in said offices, control means in said tandem oflice, an operators position having cord circuits in said first oiice, a trunk extending between said rst and said tandem oflices having an appearance in the switching mechanismA of said rst oiiice and a lamp and jack appearance at said operators position for each of a plurality of charge rates for calls from said line to desired lines terminating in said terminating ofiices, means operated upon the seizure of said trunk to prepare said control means for controlling the completion of the desired connection 'and for lighting the lamp at said operators position indicative of the charge rate for the desired connection, means operated in response tothe connection of a cord circuit of said position to the jack associated with the lighted lamp to enable the operator to request and to check the deposit of a coin or coins in payment for the initial period of conversation, means responsive to the disconnection of said cord circuitfrom said jack for y signaling said control means to proceed with the control of the completion of the desired connection, means operative upon the response of the called subscriber to start the measurement of an initial period for conversation, means effective just prior to the termination of such period for causing the collection of the deposited coin or coins, and means operative at the end of such period for ashing the lamp previously lighted to inform an operator that said initial period has terminated.

7. In a telephone system, a rst oiiice, a coin box line terminating therein, a tandem ofce, terminating oi'lices, switching mechanism in said oces, control means in said tandem oice, an operators position having cord circuits in said first oice, a trunk extending between said iirst and said tandem oiTices having an appearance in the switching mechanism of said rst oice and a lamp and jack appearance at said operators position for each of a plurality of charge rates for calls from said line to desired lines terminating in said terminating offices, means operated upon the seizure of said trunk to prepare said control means for controlling the completion of the desired connection and for lighting the lamp at said operators position indicative of the charge rate for the desired connection, means operated in response to the connection of a cord circuit of said position to the jack associated with the lighted lamp to enable the operator to request and to check the deposit of a coin or coins in payment for the initial period of conversation, means responsive to the disconnection of said cord circuit from said jack for signaling said control means to proceed with the control of the completion of the desired connection, means operative upon the response of the called subscriber to start the measurement of an initial period for conversation, means effective justv prior to the termination of such period for -causing the collection of the deposited coin or coins, means operative at' the end of such period for ilashingthe lamp previously lighted, and means responsive to the connection of a cord circuit to the jackv associated with the flashing lamp to enable the operator to converse `with said calling person, to supervise on the connection and to cause the collection or refunding of any coins subsequently deposited in payment for overtime periods of conversation.

8. In a telephone system, a rst ofce, a coin box line terminating therein, a tandem oiiice, terminating offices, switching mechanism in said oices, control means in said tandem office, an operators position having cord circuits in said rst cnice, a trunk extending between said first and said tandem oiiices having an appearance in the switching mechanism of said rst office and a lamp, an answering jack and a splitting jack appearance at said operators position for each of a plurality of charge rates for calls from said line to desired lines terminating in said terminating offices, means operated upon the seizure of said trunk to prepare said control means for controlling the completion of the desired connection and for lighting the lamp at said operators position indicative of the charge rate for the desired connection, means operated in response to the connection 0f a cord circuit of said position to the answering jack associated with the lighted lamp to enable the operator to request and to check the deposit of a coin or coins in payment for the initial period of conversation, means responsive to the disconnection of said coi'd circuit from said jack for signaling said control means to proceed with the control of the completion of the desired connection,v means operative a predetermined period following the response of the called subscriber for causing the collection of the deposited coin or coins and for flashing the lamp previously lighted at the end of the initial period allowed for conversation, means responsive to the connection of a cord circuit to the answering jack associ'ated with the ashing lamp to enable the operator to request and to check the deposit of a coin or coins for an overtime period of conversation9 and means eiective upon the connection of another cord circuit with the splitting jack associated with the flashing lamp to enable the operator to talk with either the calling person or the called subscriber but to prevent the calling person and called subscriber from talking with each-other.

9. In a telephone system, a first office, a coin box line terminating therein, a tandem office, terminating offices, switching mechanism in said offices, control means in said tandem oice, an operators position having cord circuits in said first office, a trunk extending between said rst and said tandem offices having an appearance in the switching mechanism of said :("irst` oiiice and a lamp, answering jack and splitting jack appearance at said operators position for each of a plurality of charge rates for calls from said line to desired lines terminating in said terminating oices, means operated upon the seizure of said trunk to prepare said control means for controlling the completion of the desired connection and for lighting the lamp at said position indicative of the charge rate for the desired connection, means operative following the connection of a cord circuit of said position to the answering jack associated 'with the lighted lamp for enabling the operator to request and to check the deposit of the required coin or coins, and means responsive to the connection of another cord circuit to the splitting jack associated with the lighted lamp in the event the calling person does not respond and has left the station without restoring the receiver to the switchhook for preparing the trunk and tandem oice apparatus for restoration to its normal condition upon the disconnection of said cord circuits from said jacks. N

CHESTER E. BROOKS. ERLON W. IFLINT.