US1909025A - Measured service telephone system - Google Patents

Description

May 16, 1933.

v. s. THARP 1,909,025

, MEASURED SERVICE TELEPHONE SYSTEM Filed Jan. 17, 1931 3 Sheets-Sheet 1 figg.

May 16, 1933. v. s. THARP MEASURED SERVICE TELEPHONE SYSTEM 3 Sheets-Sheet Filed Jan. 17, 1931 May 16, 1933.

V. s. THARP MEASURED SERVICE TELEPHONE SYSTEM 3 Sheets-Sheet. 3

Filed Jan. 17, 1931 Patented May 16, 1933 UNITEDk STATES PATENT OFFICE VICTOR S. THARP, 0F ELMHURST, ILLINOIS, ASSIGNOR', BY MESNE ASSIGNMENTS, TO

INC., OF CHICAGO, ILLINOIS, A- CORPORA- ASSOCIATED ELECTRIC LABORATORIES,

TION OF DELAWARE MEASURED SERVICE TELEPHONE SYSTEM Application iled January 17, 1931. Serial No. 509,330.

The present invention relates to measured-service telephone systems, but more particular to automatic measured-service telephone systems of the type commonlyr as the operation of the regular subscribers call meters, is controlled by booster battery.`

In present automatic l measured-service ltelephone systems, wherein a yregular subscribers meter is operated by a boosterbattery impulse supplied by the final switch of the switch train responsive to the answering of the called party, it is the practice to provide paystation apparatus, such as a paystation repeater, which is prepared for the coin-collect operation by the reversal of call is from a paystation. `be provided for both of these omissions.

the battery feed by the final switch when the called party answers, the collecting operation taking place upon the termination of the connection. In all telephone systems there are many calls for which no charge is made, such as calls to the employees ofthe telephone company. In order to take 'care of this requirement in' automatic telephone installations, special groups vof automatic switches are provided. In a system such as that `just described, the final switches, commonly known as connector switches, or just connectors, are provided which willL omit the booster-battery impulse to prevent operation of `a regular subscribers meter when such ay free call is made, and which will omit the reversing of the battery feed to the calling line to prevent the operation of the paystation repeater in its coin-collect function when the free One switch can However, when a call is initiated from a manual position, such as a toll operators position, it is necessary to provide a connector switch which will reverse the battery feedfor all types of calls inorder that the manual operator may'have answering supervision. This requires another special group of connectors for extendingl calls from manual positions. y

It will be appreciatedv that, by providing a paystation repeater controlled in coincollect operations by booster-battery impulses, the number of groups ofy switches for such free-call requirements can be reduced since one group of connector switches which omit only the booster-battery impulse can be employed kfor the three classes of calls just mentioned. Thus, in systems having free service asppreviously mentioned, and the regular measured service, it is necessary to provide only two groups of connector switches, one group for regulary service which transmits booster-battery, impulses for vmeter operations or coin collections and reverses battery feed for manual supervision, and kanother group of connectors which omits the booster battery, but reverses theY ated at paystations, the arrangement whereby it is impossible to extend. a call beyond a certain point ron regular paystation calls y ifa vcoin has not been deposited, the metering of all completed calls over a paystation line, and others not specifically mentioned, are the same as those disclosed in the United States Letters Patent No. 1,644,968, issued on October 1v1, 1927 to JohnWicks, while the paystation repeater of the presenty invention mayV be considered as an improvement of the paystation repeater of said Wicks patent. y A

There are other objects and features of the invention not now specificallyv mentioned which will` be described together withthe foregoing, hereinafter withv ,referencey tor the accompanying drawings. Y

Referring now to thek drawings comprising Figs. l to 3, inclusive, the general schemeV diagrammatically shown therein may be briefly describedV asfollows: the substation A, Fig. l, is-of the ordinary automatic type having the usual talking instrumentalities and an impulse sender, or calling device, S1. Being a measured-service substation, there is also provided at substation A,l a well-known type of coin-collecting mechanism which may be of the type shown and described in United States Letters PatentNo. 1,048,219, issued November 5, 1912 to O. F. Forsberg.

The line conductors 11il and 12 extend from the paystation A to the exchange, terminating at the latter point in an individual trunk-selecting switch, or lineswitch, C. This switch is of the well-known rotary type in which the wipers have no normal position, always remaining in engagement with the bank contacts associated with the trunk line last used, and the function of which it is to extend the line when calling to a trunk line which terminates in an idle selector switch. One of the trunk lines, to which the lineswitch C has access in common with a plurality of other lineswitches, is shown extending to the selector E1, Fig. The relay equipment in Fig. 2 indicated by the reference character D is a repeater, and there is one such repeater inserted in each selector trunk to which the lineswitches of the paystation lines have access. Associated with the repeater are the alarm signal and supervisory circuits shown in Fig. 2A which perform the function of notifying the attendant in thee'xchange immediately anything goes wrong with the repeater D.

The substation A2, Fig. 3, is one of a pluralityof substations which are provided for the regular subscribers and has the usual talking instrumentalities and the impulse sender, or calling device, S2. rlhe line connecting the substation A2 with the exchange terminates at the exchange in the lineswitch C2 which is similar to the lineswitch C and is individual to the line of substation A2. Associated with the lineswitch C2 is the Y boOster-battery-operated call meter M which is well known in the telephone art and which needs no further description than to say that it is operated by a booster-battery impulse to register a completed call.

The function of the lineswitch C2 is to extend the line of substationv A2 when a call is initiated thereat to the group ofselector switches of which the selector E2 is one.

A'ri operators position is represented by the jack J and the trunk connecting this position and the automatic Aexchange terminatesin the exchange in the lineswitch C1, the function of which it is, when the operator inserts a plug inthe jack J, to extend the operators trunk to the selector switch E2 or a similar selector switch. The operators position is provided with a calling device, not shown, which is similar to the calling devices S1 and S2 and by means of which the operator operates the switches to extend calls to the substations in the automatic exchange.

The selector switches E1 and E2 are the first in the series of numerical switches which, in the present showing, include also the connector switches H and H1, and which are employed to complete talking connections between calling and called subscribers. In systems employing first and second selectors, or even third selectors, the selectors El and E2 will be the first selectors.

These selectors E1 and E2 are of the wellknown Strowger vertical and rotary type, and have access to trunk lines extending to groups of connectors represented by connectors H and H1. The selector E1 is a special selector and is accessible only to paystations such as substation A, it is special in that a high resistance is included in the release trunk of the switch for a purpose which will be explained subsequently. A selector of this character is shown and described in the aforementioned lVicks patent. The selector E2 is a regular selector and differs from the selector E1 only in that the high resistance has been omitted from the release trunk. Since Strowger selector switches are well known to those skilled in the art of automatic telephony, the selectors E1 and E2 have not been shown in detail but represented by rectangles.

The connector H is one of a group of similar connectors accessible to the selectors E1 and E2 and is of the well-known Strowger vertical and rotary type. Connector H is ar anged to reverse the battery feed through the' preceding switches and to transmit a booster-battery impulse through the selectors, when a called party responds, to operate the meter M when a call is extended from the substation A2 and to control the repeater D to initiate the coin-collect operation when the call is extended from the paystation A. This' connector has access to the Vlines of substations such as substation A3,

for calls to which a charge is made.

The connector H1 is similar to the connector H except that the means for transmitting a booster-battery impulse has been omitted from this connector. This connector has access only to the telephones of o'cials and employees of the telephone company for calls to whom no charge is to be made.

To those versed in the art of automatic telephony, a connector switch such as H is known as a booster-battery connector, while one such as H is known as a regular reversebattery connector.

lt is customary in automatic telephone changes to provide a special group of secondY selectors which have access to trunks for fire and police calls, recordino` operators and such, which type of calls may be initiated from paystations without it being necessary fork the callingparty to insert a coiny in thek coin-collect mechanism at the paystation to complete the call.` These selectors have not been shown on thedrawings, but, merely indicated by an appropri-` ate legend since theydo not constitute a part.

of this invention. They have been mentioned merely to explain the purpose of the resistance in the release trunk of the selector E1 when the time comes. These selectors may be identical to the selector E1 and 'function in a manner described in the aforementioned Wickspatent. y

Inorder to explain the operation of the circuits, it will first be assumed that aparty wishes to extend ya callffrom paystation A to substation A3 and that the party attempts to do so without first depositmg a coin in the coin-collect mechanism at the paystation. y

Vhen the receiver is removed atsubstation 4A, the line relay 26 of the individual lineswitch C is energized over the two sides of the calling line in series. Relay 26, upon operating, at its armature 40 completes a vcircuit which includes the switching relay 25 and the motor magnet 27 in series, and yat its armature 39, connectsY the test wiper 46 to the above circuit at a point mid-way between the switching, or cut-0H, relay 25 and said motor magnet. The operation ofthe lineswit'ch C depends upon whether the trunk line with which its wipers 44to 47, inclusive, arein engagement is busy or not. Assuming this trunk line to be busy,there will be a ground potential present upon the test contact engaged kby the test wiper 46, the switching relay 25 will be short circuited, and the motor magnet 27 will be supplied with direct ground by the test wiper and will operate as a buzzer tor advance the switch wipers step by step in search ofan idle trunk line. However, it will be assumed inthe present case that vwhen the receiver is removed at substation A, the switch wipers 44 to 47, inclusive, are in engagement with the bank contacts'associated with an idle trunk line. Under these conditions, immediately following theenergization of; the line relay 26,'the. switching relay 25, not being short-circuited, will energize. Upon ener,- gizing, relay 25 disconnects the line conductors 11 and 12 of the calling substation from the winding of the line relay 26 and from ground, respectively, and extends them by way of armatures 33 kand 36, wipers 44 and 47.V bankvc'ontacts 52gand' 55, conductors 48 and 51', armatures 145 and 144 and their resting contacts, armatures 160 and 164 and theirI resting contacts, upper and lower windings of the differential relay 130, and thence through the winding of the line relay 135 and the winding of the-impedance coil 1397to battery and ground respectively. The

line relay 135 of the yrepeater, D, Fig. 2, is

energized over the two sides of the calling line in series and at its larmature 183 completes the circuit of the slow-to-release relay 136 from ground by..way of armatureV 162 and resting Contact of relay 128. `Relay 136 thereupon energizes and, at its armature 186, places ground on release-trunk conductor 50 by way of the retardation coil 138, thereby establishing al holding circuit for lineswitch wiper 46, armature 35 and its'make contact, winding of'relay 25, and thencev through the winding of motor magnet 27 to battery.,` It will beunderstood that this holding circuit is completed before the slow-to-release relay 26 hashad time to deenergize after its circuit was opened by relay 25. kA branch of the holdingcircuit also extends by way of private normal conductor` 30 to the multipled test contacts inthe banks of connector switches which have access to the line of substation A, wherebyihat line is protected from intrusion in 'the well-known manner. It will be remembered that ground is supplied tov the release-trunk conductor A`50 through the retardation coil 138. This/,coil is of a very low resistance, of about two and one half ohms, so that themultiples of the test contacts accessible to other lineswitches are made busy.

Relay 136, upon'` energizing, also completes l at its armature 188 a circuit for the polarizing windingof the electro-polarized `relay 132 in series with the winding of relay 141.

ed that current flowing inA its .polarizing winding does not vcause this relay to operate its armature, though after once operating, the current flow in the polarizing winding is .suicient tomaintain the armature attracted.

Relay 141 is, therefore, the only relay operated in this circuit. Relay 141, upon energizing, opens a point in a certain shunt circuitwhich willbe rvdescribed later.

kVVhenthe `line relay 135 of the repeater D' energizes, a bridge circuit is closed across ,the trunk conductors 200202, which may kclosure of thisbridge circuit, theline relay of the selector E1 is energized. Upon energizing that line relay` completes the circuit of the slow-acting release relay of theselector E1y which latter relay immediately operates to prepare the operating circuits of the selector E1 in the usual manner and-to placeground on the release-trunk conductor The electro-polarized relay 132 is so adjust;

C whichextends by way of bank Contact 54, 75

are connected,` the test Wiper of the selector 201 vthrough the previously-mentioned high resistance with which' the selector ElV is equipped. This ground extends back over the release-trunk conductor 201 to the polarizing winding of the relay 132 in the repeater D. The relay 141 is 'not short circuited at this time as the resistance in the release trunk of the selector E1 is high enough to prevent the relay winding from being shunted. Ground is now supplied to the polarizing winding of relay 132 from the selector E1 and from the repeater D.

Before proceeding further with the explanation, attention is called to a shunt circuit around armature 184 and its front contact which, it may be mentioned, are the impulse springs ofi the repeater D which control the operation of the selector E1 and the succeeding switches. This shunt circuit extends as follows: from armature 184 by way of back contact and armature 196, armature 180 and its back contact, armature 189 and its front contact, tothe front contact of armature 184. The contacts at armatures 180 and 189 are closed, but, since relay 141 is energized, armature 196 will be in an attracted position and the shunt circuit will be opened at that point, it being clear from this explanation thatthe shunt circuit will not interfere with the operation of the impulse springs, represented by armature 184 and its working contact, in repeating impulses.

The calling subscriber at substation A may now operate his calling devicein accordance with th'e first digitof the number which it is necessary to call in order to obtain connection with the substation A3. By the operation of the calling device S, a series of interruptions is produced in the circuit of the line relay 135, thereby causing this relay to deenergize'in responseto such interruptions,

each time opening the previously-traced bridge circuit of the linerelay of the selector El. The selector' E1 thereuponfunctions in the well-known manner to elevate its wipers opposite the level of bank'contacts represented by the number of impulses comprising the first digit and then automatically rotates its wipers to select a trunk leading to an idle connector such as 'the connector H. Inasmuch as the connector -H is shown as accessible to the selector E1 over the ninth level of bank contacts, it necessarily follows that the first digit which the-subscriber dials is nine. The test wiper of the selector El will encounter ground on the test contacts of the busy connectors of thegroup, but will come to rest in the well-known manner when an idle connector is found.

f Assuming that the connector H is the rst idle connector of the group to be found, when the wipers of the selector El are placed in engagement with the bank contacts to which the conductors 203 to 205, inclusive,

will not encounter ground on the conductor 204 Vand the selector will thereupon function in the well-known manner to extend the trunk conductors 200 to 202, inclusive, to the bank multiple conductors 203 to 205, inclusive. When this is done, the line relay 215 of the connector H energizes over the following circuit; from ground, through the upper winding of relay 215, normally-closed cont-acts controlled by armature 252 of the back-bridge relay 249, line conductor 212, multiple conductor 203, upper line wiper and line conductor throughthe selector E1, trunk conductor 200, thence over the previouslytraced bridge circuit inthe repeater E to the trunk conductor 202, lower line conductor through the selector E1 and the lower line wiper, conductor 205, conductor 214, normally-closed contacts controlled by armature 253 of relay 249,.-and through the lower winding of the line relay 215 to battery. The line relay 215 energizes in this circuit, and upon operating at its armature and make Contact, completes the circuit of the slow-acting release relay 210. Relay 216 thereupon operates and at its armature 217 connects ground to the release-trunk conductor 213 by way of normally-closed contacts controlled `by armature 250 of relay 249. Ground is fed to the repeater D by Way of release trunk conductor 204, test wiper and release-trunk conductor of selector El, to the release-trunk conductor201 of the repeater D. Since there is no high resistance in the release trunk of the connector H, the direct ground will short circuit the relay 141 of the repeater D, which relay will thereupon deenergize and at its armature 196 and resting Contact Vclose the shunt circuit about the impulsing armature 184 of the line relay 135 of the repeater D. It can now be seen that with'the shunt circuit completed about the impulsing armature 184 that further operation of the line relay 135 will have no effect upon the connector H and the call can be extended no further. In order that this shunt circuit might not be completed around the impulsing armature 184, it is necessary that the calling party the coin-collect mechanism at the paystation A.

Returning now to the point in the description where the calling party first operates his calling device S1, a function of the repeater D to improve the impulsing circuit will -now be explained. When the line relay 135 of the repeater D first deenergizes in response to the first Vinterruption in its circuit, an impulse of current is transmitted by way of armature 183 and back contact to the slowto-release relay 137. This relay thereupon energizes and in operating, at its armature 191 and make contact, completes, from ground by Way of armature 186, the circuit of relay 129 "through the r'iormally-closed and lower windings of therdifferential relay 130 included in the impulsing circuit of the line relay 135. Another result of the energization of therelay 137 is that at armature 190 and its-make contact a direct bridge is placed across the trunk conductors 200 and 202 which does not include the upper winding of the relay 133 and the lower winding of the relay 132. These circuit changesy are made in order to reduce the resistance and impedance of the switch control circuit to a minimum during the transmission of the impulses.

`rlhe operation of the system in the case where the subscriber at station A deposits a coin before calling ther desiredsubscriber will now be described and in this connection, the process of collecting the coin at the termination yof the conversation will be briefly described. The first operation on the part of the person at substation A isto deposit coin of suitable denomination in the coin-collecting mechanism provided for that purpose. Thisfmechanism is well understood and its operation need not be explained in detail. When the coin is deposited it descends past the trigger mechanism which is released by the 'coin with the result that the polarized magnet of the coin-collecting mechanism is connected to the line n conductor 12. The coin is held in suspense by a trap-door drop where it is Vadapted to be either collected or refunded Yunder control of the polarized magnet. The coin may be deposited either before or after the receiver is removed. In either case, the latter operation brings about the operation of the rotary line switch C, whereupon the line isv extended to an idle selector as has been described. Assuming that the `selector El, Fig. 3, is the switch to which connection is extended, the operation is the same as has already been described and will not be repeated, with oneexception, however; when the line conductors 11 and 12 are connected by the operation of the lines'witch C'to the windings of the line relay 135 and the impedance coil'139, of the, repeater D, the

ground on line conductor 12 through the polarized magnet of the coin-collecting mechanism imbalances the differential relay 130 which is included in the line circuit and causes this relay to energize. It may be stated at this point that the polarized magnet at the substation is of high resistance and does not materially interfere with the transmission of operating impulses or with the talking circuit, but it is nevertheless sufficient to cause the relay 130 to operate as described.

Upon attracting its armature 170, relay 130 closes a circuit for relay 134L by way of resting Contact and armature 191 and armature 186 and its make contact to ground, which latter relay,-upon energizing, 'establishes a locking circuit Vfor itself at its armature 178 and make contact, locking itself to the release trunk conductor* 201. VRelay 134, at its armature 181, prepares a circuit which will be described' subsequently, and .atl it-s armature 180, opens the shunt circuit around the impulsing armature 184, by this last operation obviously permitting the extension of a call regardless of the operated or non-operated condition of the relay 141.

The party at the paystation A may now yoperate his callingk devicein accordance with the digits of the number of substation A3". The selector E1 will respond to the first digit to extend vthe trunk line conductors 200 to 202 into connection with the multiple conductors 203205, inclusive, of the vconnector- Hand the line relay 215 and the slow-'acting release relay 216 of the connector will respond as described. vIn addition to connecting ground to the release-trunk conductor 213 by its armature 217, the release relay 216 at its armature 218 completes the circuit' of the slow-to-release relay 246 by way of armature 224 and yrestingcontact of the ring-cut-ol' relay 222. Ground is supplied by the armature 218 to the conductor 255 which serves as a holding conductor for'the relays in the connector. At its armature 219, relay 216 prepares the impulsing .circuit for the magnets of the connector.. Rela 246 energizes in the previously-traced circultand at its armature 248 prepares -a locking circuit for itself, and at its armature 247 Vand make contact prepares the circuit for suV plying the booster-battery current from tiie battery B.

The line relay 215 responds to the first series of impulses received by the connector H through the selector El by retracting vits armature a corresponding number of times to transmit impulses by way of armature 219 and make contact of relay 216 through the series relay 220 to the vertical magnet 221. The vertical magnet 221 responds to the impulses toelevate the Wipers opposite the level of bank contacts corresponding to the level in which the contacts of the line of substation A3 appear, while the relay 220 energizes upon the first impulse andprepares another impulsing circuit for the vertical magnet 221 which is completed when' pulses, the relay 220 deenergizes and retract-s its armature so that when the line relay 215 responds to the next or last series of impulses, the impulses transmitted by that relay will be conducted through the armature and resting contact of relay 220 and thence by Way of resting contact and arman ture 230 of relay 228 to the sloW-to-release relay 231V and in parallel to the rotary magnet 254. the impulses to the latter traversing the path including the armature 243 and resting contact of the switch-through relay 237. Rela-y 231 responds to the first impulse of the rotary series, and at its armature 232 connects the test Wiper of the connector to the Winding of the busy-test relay 228 and at its armature 234, completes an impulsing circuit for the rotary magnet 254 Which is independent of the resting contact and armature 230 of relay 228, so that as the Wipers of the connector are rotated over contacts of busy lines by the operation of the rotary magnet 254 in response to the impulses delivered by the line relay 215, the connector Will not be stopped in engagement withr one of these busy lines by the opening of the rotary impulsing circuit at armature 230 of relay 228. Then the last series of impulses ceases, the Wipers of the connector Will be in engagement with the bank con tacts to which the line conductors of substation A3 are connected.

If the called subscribers line is busy at this time, ground Will be encountered by the test Wiper of the connector and a circuit Will be completed from that ground for the busy-test relay 228 since the relay 231 is sloW-to-release and Will maintain its arma` ture 232 in engagement with its make contact for a short interval after the cessation of impulses. Relay 228 immediately ener gizes When its circuit is completed, and at its armature 229 prepares a locking circuit for itself Which will be completed with the retraction of armature 232 of relay 231 before that armature disengages its make contact, and at its armature 230 it opens the impulsing circuit of the rotary magnet 254 to prevent further operation ot' that magnet. Relay 228 also connects busy tone to the line conductor 212 through the condenser which tone is heard by the calling party and informs that party that the desired connection is busy.

Assuming, however, that when the Wipers of the connector H are moved into engagement with the bank contacts of the linevof substation A3, the line is idle. Therefore, no` 'ground Will be encountered by the test Wiper and no circuit will be completed for the busy-test relay 228. Consequently, when relay 231 deenergizes, at its armature 232 and back contact it completes the following circuit :'r'or the switch-through relay 287 ground threue'h armature 217 and make contact of relay 216, armature 229 and resting contact of relay 228, lower Winding of switch-through relay 237, resting Contact and armature 232 of relay 231, test wiper of the connector and the private normal conductor of the line-switch C3 which is individual to the line oi substation A3 to battory through the Winding of the cut-olii relay of that lineswitch. The relay 287 and Athe cut-oli relay of the lineswitch C3 energize in this circuit. The cut-oli:1 relay of the linesWitch C3 operates in the wellknown manner to disconnect the line relay of the lineswitch from the line and. relay 237 at its armature 242 locks itself to the holding conductor 255, at its armature 240 supplies an additional ground to the test Wiper of the connector to mark the line of substation A3 busy to other connectors of the group of which connector H is one at its armatures 239 and connects up the ringing generator G to the called line, at its armature 238 connects a ring-back tone to the line leading back to the paystation A to inform the calling party that the desired line is being signalled, at its armature 241 opens a point in the circuit of busy-test relay 228 to prevent any possible operation or" that relay, at its armature 243 opens a point in the` circuit of the rotary magnet 254, and at its armature 244 opens a point in the circuit of the release magnet 235.

Ringingcurrent from the generator G is now supplied to the called line and the called subscriber is now signalled. `When the called subscriber ansuf'ers, the loop circuit including the called line is completed for the ring-cutotl relay 222 which thereupon operates and at its armature 226 locks itselt` energized to the holding conductor 255. Rel lay 222 at its armatures 223 and 227 extends the talking conductors through the connector to the called line, thereby disconnecting ringing current and completing the circuit of the back-bridge relay 249. Relay 222 also at its armature 224 opens the original energizing circuit of the sloW-to-release rclay 225 and at its armature 245 completes a locking circuit for that relay.

Back-bridge relay 249 energizes when itsI circuit is completed by the response ot the called party and the consequent operation of the ring-cut-off relay 222 and, upon energizing, at its armatures 252 and reverses the connection of the line relay 215 to the line conductors 212 and 214 to reverse the flow of talking current back to the repeater D. Relay 249 at its armature 251 opens the locking circuit of relay 246 which Was just completed, and at its armature 250, connects booster-battery current 'from the battery B to the release-trunk conductor 213. The relay 246 because ot its slmr-to-release feature remains operated tor an interval after its locking circuit is opened by relay llO conductor 201.

This reversal in the current flow through the calling line extending Vthrou h the repeater D causes a reversal of t e current How through theA bridge of the repeater, thereby causing the energization ofthe electro-polarized relay 132.y The electro-polarized relay 132 is so adjusted that it will attract its armatures Whenthe current is reversed in its lower winding and will maintain its armature attracted by means of its polarizing winding eveny if the. circuit of its lower winding is subsequently open. However, if the current flow in its lower winding is restored to normal, it will retract its armature. Relay 132, upon operating, at its armature 175 opens a point in the circuit of relay 131, thereby preventing the latter relay from energizing at this time. The lower winding of relay 132 is included in the talking circuit, but, is shunted by the non-inductive resistance 193 which affords a path for voice current so that the talking efficiency of the circuit is not materially affected. v

The impulse of booster-battery current connected to the release-trunk conductor 213 of connector H and through'the selector E1 to the release-trunk conductor201 extending to the repeater D causes the operation of the booster-battery relay 128 which, upon operating, at its armature 163 locks itself energized through its lower winding yto the release-trunk conductor `201. Relay 128 upon operating,a1so completes the circuit of the slow-acting relay 127 at armature 162, andat armatures 160 and 164 disconnects the incoming line conductors 48 and 51 from the windings of the rela 135 and the impedance coil 139 and'exten s them direct to the windings of the line relay 215 of the connector H. Another result of the energization of relay 128 is that a circuit is com-V pleted from ground by way of front contact and armature 161, conductor 49, bank contact 53, Wiper 45, front contact andarmature 34, and through the Winding of the meter 'magnet 28 to battery. vMagnet 28 operates to register the completed call in the usual manner. Relay 127, upon ener- .gizing, at its armature 156 completes an additional holding circuit for the lineswitch C, and at armature l155 prepares certain of the coin-collect circuits which will be described later.

Conversation now takes place and when terminated, both subscribers replace their receivers upon the switchliooks. When the receiver is replaced at the calling substation A, the line relay 215 in the connector H is deenergized as is the slow-acting relay 216. The latter relay, upon deenergizing, closes a point in the release circuit of the connector `H at armature 219 and its resting contact,

at armature 217 removes ground from the release-trunk conductor 213, andV at its armature 128 removes one ground connection from the connector holding conductor 255.

By the removal of ground from the release-trunk conductor 213, the holding circuit of the selector El is opened and this switch releases. Ground being removed from the release-trunk conductor 201, one ground connection previously 'having been removed from that conductor by the release of the relay 136 following the discolmection of the line relay 135 from the calling line `by the operationof the booster-battery relay 128, the relays 128 and 132 in the repeater D are deenergized. Relay 132, upon deenergizing, prepares the circ-uit of the relay 131 at armature 175 and its resting contact.

Relay 128, upon deenergizing, opens the circuit of slow-acting relay 127'. Before this latter relay hasr had time to deenergize, an impulse of current is sent over the following patli: ground by way ofarmature 162 and its back contact, armature 157 and its fronty Contact, and thence through the winding of the slow-acting relay 125 to battery. Relay 125, upon energizing, places an additional ground on the release trunk `conductor 50, extending backA to the lineswitch C, at armature 146, and at armature 147 completes a circuit extending from ground by way of front contact and said armature, conductor` 107, through the winding of relay 71, Fig. 2A, to battery. Another result of the energization of relay 125 is that at armatures 145 and 144, both sides of the' linejof the substation A are Opened and at the front contact'of armature 144 the battery lead 105 from'the battery B2 is connected to the line conductor 12 over the following path: battery B2, resistancey lamp L', conductor 105, front contact and armature 155, back contact and armature 177, through the Winding of relay 140, front contact and armature 144, conductor 51, bank contact 55, wiper r47, front contact and armature 36, to the line conductor 12. Upon the closure of this cirture 195 a circuit for the slow-acting relay 126. Relay 126, upon energizing, closes at its armature 149 a circuit for the supervisory lamp L5, at its armature 150 completes a locking circuit tor the relay 127 which, heing slow-acting has not yet deenergized, and at armature 143 connects the interrupter l. to the lower winding of relay 133, relay 134thaving deenergized when ground was removed from the release trunk conductor 201 and retracted its armature 179.

Ordinarily the polarized magnet at substation A will respond at once to current from battery B2 and willr operate to collect the deposited coin and will restore the ent-ire coin-collect mechanism to a normal condition instantly, at the same time disconnecting line conductor 12. However, it sometimes happens that the armature of the polarized magnet sticks and the relay 133 is provided to assure the collection ot the coin in such a case. T ie interrupter l causes relay 133 to vibrate its armature and interrupt the circuit ot the battery B2 at its armature 177, or the battery B1 in case this battery is included in the circuit, intermittently energizing the polarized magnet, this operation being ordinarily effective to lree the armature in case it should stick. However, should the armature of the polarized magnet continue to stick, the relay 126 will remain energized.

It kwill be remembered that relay 125, upon energizing, completed a circuit extend ing from ground by way of 'front contact and armature 147, conductor 107, through the winding of relay 71 to battery. Relay 71, upon energizing, closes the circuit ot the high-resistance relay 69 at armature 91 at armature 93 completes a locking circuit for itself, and at armature 92 closes a circuit which extends over the following path: ground by way of armature 92 and front contact, resistance 97, through the winding of relay 68 to battery. Relay 68, upon energizing, completes a circuit extending from ground by way of front contact and armature 88, kthrough supervisory lamp L3, through the winding of relay 67, and through the winding or" relay 66 to battery. Relay 66 is ot such high resistance that relay 67 is not energized nor the lamp L3 lighted in series with it though it receives suiiicient current to energize. Relay 66, upon operating, completes the circuit of the solenoid 60. The solenoid immediately operates to pull up its plunger arm 75. This operation takes considerable time as the movement of the armature is retarded by means ot a dash-pot. The relay 69, upon energizing, closed a circuit tor the relay 70 which energized and opened the locking circuit ot the relay 71. It the coin is not collected at the substation A, there will still be ground present upon the conductor 107 and the relay 71 will be maintained energized and consequently the solenoid will finally attain its operated position. Then this occurs, the springs 77, 78, and 79 will be forced into engagement by the arm 76, completing a circuit extending 'from battery by way oi springs 79, 73, and 77, winding of relay 65, winding of relay 67, lamp L3, armature 8S and its front contact to ground. It will be seen that this circuit short circuits the relay 66 which thereupon deenergizes. The lamp L3 is lighted and the rela-y 67 operates over this circuit. Relay 67, upon energizing, completes the circuit of the supervisory lamp L2. The lamp L2 is a general supervisory lamp and is common to several groups of switches, while the lamp L3 is individual to a particular group of switches. Relay 67 at its armature 8 9 also closes the circuit ot an alarm, whereby the attention ot the exchange attendant is attracted. The attendant, upon seeing the lighted condition ot the lamps L2 and L3, will note the nature ot the trouble and will go to the particular group ot switches designated by the lamp L3. A lamp L5 is individual to each repeater such as D, and by the lighted condition ot this signal the attendant will know that it is this particular switch, or rather the coincollecting mechanism at the paystation, the line ot which is associated with this switch, which is causing trouble.

Another condition that this alarm signal provides for is that in case either one ofthe batteries B1 or B2 is out oi' order, relay 69 will not be energized and the locking circuit of the relay 71 will be maintained closed even though ground is immediately removed from the conductor 107. Therefore, the signals L3 and L2 will be operated and since there is no lamp similar to lamp L5 operated at this time, the exchange attendant will know the nature of the trouble.

Returning now to the operation of the repeater D, when the polarized magnet ot the coin-collecting mechanism at the calling substation is finally disconnected trom the line, the relay 140 will Vdeenergize and open the circuit et the relay 126, which relay will deenergize also, thereby opening the locking circuit of the slow-acting relay 127. Relav 127 upon retracting its armature 157 opens the circuit of relay 125 allowing that relay to deenergize. Relay 125, upon deenergizing, removes ground from the conductor 107 at armature 14:7 and at armature 1&6 removes ground from the release-trunk conductor 50, whereupon the holding circuit ot the switching relay ot the lineswitch C is broken. 1n this manner the line equipment of substation A is restored to normal in condition for another call,

The relay 131 in the repeater D is pro* vided in order to prevent any locking up ot the switches when the called subscriber at,

before the receiver at the paystation A replaced on the switchhook, the back-bridge relay 249 in the connector H will be deenergized and battery through the lower winding of line relay 215 will be on the 10 lower heavy talking conductor.

- The battery flow over the calling subscribers line is therefore restored to normal and the relay 132 in the repeater D is deencrgized to complete the circuit of the relay 131. This circuit extends from ground by way of armature 162 and make contact of relay 128, which relay is in its operated position since 'ground has not been removed from the release-trunk conductor 201, back contact and armature 175 of relay 132,l and then through the winding of relay 131 toA battery. Relay 131, upon energizing, re-

verses the conductors 202`and 200 with regard to the subscribers line at its armatures 172 and 173 in order to prevent the line relay 215 of the connector H from remaining energized in series With the polarized ma net at the subscribers station A after the cal ing subscriber hangs up. When the calling subscriber hangs up, the release 0f the connec-y tion and collection of the coin' will take pla-ce in the manner as before described.

Returning now to the operation of the connector H, it will be assumed that the calling subscriber at paystation A re )laces his receiver upon the switchhook be ore the called subscriber at substation A3 does. The line relay 215 immediately deenergizes and opens the circuit of the slow-acting relay 216. Since the back-bridge relay 249 is still in its energized position, ground will be present upon a holding conductor 255 by Way of armature 225 and make contact of cut-oil' relay 222 and armature 251 and makecontact Vof relay 249. Therefore, the connector H will be held until the called `subscriber hangs up. When this takes place, the backbridge relay 249 will energize and remove ground from the holding conductor 255 thereby openingthe locking circuit of relays 222 and 237. Relay 237 upon deenergizing y retracts its armature 244 to complete the circuit of the release magnet 235 which circuit is as follows: ground by Way of armature and resting contact of line relay 215, armature 219 and resting contact of relay 215, armature 244 and resting contact of relay 237, off-normal springs 236, through the winding of release magnet 235 to battery. The release magnet 235 thereupon energizes and restores the connector H to normal in the Well-knownr manner.

In case the called subscriber does not answer or the calling party at the paystation A hangsk up befQre the Called subscriber answers, it will be necessary to refund the deposited coin rather than collect it. In either case, whenthe calling party replacesI the receiver thel refund operation must be initiated. This refunding operation will now be explained. Since the called `sub scriber did not answer, neither the boosterbattery relay 128 nor' the polarized relay 132 are energized and noci'rcuit will have been completed for the slow-acting relay 127 or the meter magnet 28 yassociated with the lineswitch C. Therefore, when the calling subscriber hangs up his receiver, the line relay 135 deenergizes and sends an impulse of current to the slow-acting relay 137, at the same time opening the circuit of slow-acting relay 136. Relay 136 thereupon deenergizes and completes the following locking circuit for theV relayv137: ground by Way of armature 162 and resting cont-act of relay 128, armature 185 and resting contact of relay 136, armature 181 and make contact of relay 134, through the winding of relay 137 to battery. Relay 135, upon deenergizing,at its armature 184,'opens the bridge circuit, thereby causing the release of the selector E1 and the consequent removal of ground from the release-trunk conductor 201, thereby unlocking the relay 134 since one ground connection was also removed from the release-trunk conductor 201 by the retraction of armature 188 of relay k136. A

- Relay 134, upon deenergizing, at its armature 181 opens the locking circuit of relay 137. Before relay 137 has had time to retract its armature, an impulse of current is transmitted'from ground by Way of armature 162 and its resting contact, armature 185 and its resting contact, armature 181 and its resting contact, make contact and armature 192 of relay 137, and. thence through the winding of relay 125 to battery.

Upon energizing, relay 125 operates as bey fore described, except that in the present case since relay 127fis deenergized, the battery lead 106 from the battery B1 is connected to the line conductor instead of the battery lead 105 of the battery B2. Current iow from the battery B1 now operates relay 140 rand the polarized magnet at the calling substation A in series, the polarized magnet now being actuated to refund theV deposited coin rather than collect it. Upon energizing, relay 140 completes the circuit of slow-acting relay 126 which operates to close the holding circuit of relay 125 by way of armature 150 and `make contact and armature 158 and resting contact of relay 127. The energization of relay 126 also produces certain other circuit changes which have been explained before.

When the circuit is broken'by the polarized magnet at the calling substation being disconnected from the line conductor 12, the relay 140 deenergizes and opens the circuit of relay 126 which deenergizes also. As a result of the deenergization of relaj.7 v126,'the holding circuit of relay 125 is opened and this relay restores to normal, thereby removing ground from the holding conductor 50 to allow the linesn-itch C to restore to normal, thereupon all the apparatus Will have been released.

Should the coin-collecting mechanism at the paystation fail to refund the coin, the supervisory equipment of Fig. 2A will 'function as before described to indicate to the exchange attendant such failure. By the lighted condition of one of the lamps L and L1, Fig. 2A, the attendant will know which of the batteries B1 and B2 is connect-- ed to the circuit and Will therefore be able to tell Whether the paystation apparatus is at fault in refunding or collecting the coin.

Let it be assumed now that the calling party at the paystation A desires to converse with an official or an employee of the telephone company other than an operator such .as a recording o}')erator, for which type of call no charge is to be made. This type of call, however, requires that a coin first. be deposited in the coin-collecting mechanism at the paystation A before the call is initiated as in the case of the call from the paystation A to the subscriber A3. Let it further be assumed that the desired oflicial, or employee, is the one Whose telephone is represented by the substation A4, Fig. Inasmuch as substation A4 is accessible to the connector H1 and that connector is ac cessible to the selector El over the tenth level of its bank contacts, the party'at the paystation A after depositing the proper coin operates the calling device S1 for 'the digit 0 thereby causing the repeater D to repeat ten impulses to the selector El in the manner previously described.

The selector E1 in response to these ten impulses elevates its Wipers opposite the tenth level of bank contacts and then automatically rotates its wipers step by step over the contacts in the tenth level until an idle connector is found. Assuming the connector H1 to be the first idle connector found by the selecto-r E1, the selector E1 upon placing its Wipers on the contacts to which the conductors 209 to 211, inclusive, are connected, will perform its switching-through operation to connect the repeater D through to the connector H1 so that the next series of impulses repeated by the repeater D in response to further operation of the calling device S1 at the paystation A will cause the connector H1 to respond in a manner similar to that in which connector H responded, to connect the paystation line to that Yof the substation A3.

lVhen such connection has been completed and the party at station A4 has responded to the ringing of his call bells by ringing current sent out over the called line by the connector H1, the connector H1 will function to reverse the flow of current over the line conductors 200 and 202 extendingl back to the repeater D, but since, as previously stated, the connector H1 is not provided with means for transmitting a booster-battery impulse over the release-trrmk conductor 201, the repeater D will be effected only by the reversal of current flow. Therefore, the polarized relay 132 in the repeater D will operate responsive to the current reversal, but the booster-battery relay 128 will not operate. The only function performed by the polarized relay 132 upon operating is the opening of the circuit of the relay 131 at the contacts controlled by armature 175. Since the relay 128 does not operate in this connection, the relay 127 will remain inert and the release of the connection by either the calling or called subscriber causes the operation of the relay 125 which thereupon functions to connect the coin-refund battery B1 to the paystat-ion apparatus, since relay 127 is not operated, as previously explained. The coincollecting` mechanism at the paystation A thereupon functions to refund the coin to the calling party and to disconnect the polarized magnet of the coincollec'ting mechanism from the line conductor 12 to cause the release of the lineswitch C as in the case of the previously-described connection. Thus the calling party has been able to call an official or an employee of the telephone company and at the end of the conversation have his coin returned to him. Then a fire or police call, or a call to a recording or similar operator, is made from the paystation A, it is not necessary that the calling party deposit a coin in order t0 make the call because of the highy resistancefrelease trunk of the selector E1 and because the special selector accessible to the selector E1 for calls of this type is also provided with a high-resistance rellase trunk, there by preventingr the relay 141 in the repeater D from being short-circuited at any time. Since relay 1111 remains operated throughout the entire connection, by maintaining its armature 196 outof engagement with its resting contacts, that relay maintains open the shunt circuit around the impulsing armature 1811 of the line relay 135. lt is only When all switches vin a switchtrain are equipped With a high resistance in the release trunk that calls may be made Without the necessity of first depositing a coin.

lVhen the subscriber at the substation A2 initiates a call, the linesufitch C2 individual to the line of the substation A2 functions in the usual manner to select a trunk leadingto an idle selector switch such as the selector E2. lhen substation A3 is the called7 station desired by the subscriber at substation A2, the selector E2 will function in the usual manner responsive to the operation of the calling device S2 to select the trunk conductors of an idle connector switch such as the connector H. When the selection has been ycompleted the selector E2 will extend the calling line to theconneetor H, which latter switch will then operate as has already been described in response to the next two series of impulses transmitted by the calling deviceS2 to connect thecalling line to the substation A3. When the called subscriber answers the call, the connector H besides reversing the direction lof current flow in the line of substation A2, which reversal has no particular effect in this connection, transmits a booster-battery impulse over the release trunk of the calling line to the meter M associated with the lineswitch C2. The meter will thereupon be operated to register the call.

, `When the party at substation A4 is the one with whom the subscriber at station A2 desires toconverse, the selector E2 ywill be operated to select van idle connector of the group in which the connector H1 belongs.

The connector 'Hl will thereupon be operated in the usual manner to extend the calling line to the substation A4 and upon the response of the called party will connect the calling line through to the line of Vsubstation A4 and will reverse the direction of the current flow in the calling line without any particular effect. nector H1 1s not arranged' to transmit va boosterbattery impulse, the meter M of the .calling line will not be operated and no registration of the call to the substation A4 will be made.

When the toll operator at the position in which the jack J is located inserts the plug of a cord circuit in the jack J, the lineswitch Cl functions as usual to connect the toll trunk to an idle selector switch such as the selector E2. The selector E2 operates upon the transmission of impulses to select a connector switch such as either the connector H or the connector H1 corresponding to the number of impulses received. Since both of the connectors H and H1 reverse the direction of current flow in the calling line upon the response of the called party, the answering supervisory signal of the cord circuit attached to the jack J will be operated and the operator will thereby be able to know when the called party has responded. If the call is made to one of the otlicials or employees of the telephone company, for example, the one whose station'is designated as A4, and the connector H1 employed in the connection, the operator would have to listen in on the line to determine when the called party responded if the connector H1 did not reverse the direction of the current iow in the calling line upon the response of the called party.

Since cony From the `foregoing it will be appreciated that if the relay 128`of the repeater D were operated by the reversal of current in the calling line by the connector that the connector H1 could not be employed in a connection between the paystation A and substation A4 without the coindeposited by the calling party being collected upon the termination of the connection. It would,

therefore, be necessary Vto provide a conin the present invention the coinecollect op' eration of the repeater rD is dependent upon the impulse of booster battery caused by the operation ofv the connector in response to the answering of the calledparty, the special connectors may be omitted and the number of connectors reduced, thereby simplifying the automatictelephone system' and increasing the operating efiiciency ofthese two groups of switches.

The invention having been thus described, what is considered new and what it is desired to have protected by Letters Patent will be pointed out in the claims which follow.

What is claimed is:

l. In a telephone system, a calling line having a coin-collecting mechanism including an operating magnet therefor, a called line, an automatic switch, means whereby said calling line can extend a connectionfto said called line via said switch after a coin has been deposited in said mechanism, means `in said switch responsive to the answering of the calledL party for transmitting yan impulse of booster-battery current, andV means operated by said impulse for operating said magnet to manipulate said mechanism to collect the deposited coin.

2. In a telephone system, a calling line having acoin-collecting mechanism, a called line, an automatic switch, means'whereby the calling line can extend a connection to the called line via said switch after a coin has been deposited in said mechanism, means in said switch responsive to the answering of the called party for transmitting animpulse fof booster-battery eurrent,and means partially operated by said impulse and completely operated responsive to t-he breaking of said connection for operating said mechanism to collect the deposited coin. V

3. In a telephone system, a series of automatic switches including a' paystation repeater for connecting a. calling paystation line having coin-collecting mechanism and a called line in a conversational circuit, means in the tinal switch for transmitting an impulse ot booster battery current to said repeater when the called party answers, means in said repeater for collecting or re- `funding a. coin deposited in said mechanism when said circuit is broken, and means in said repeater operated by the impulse of booster-battery current tor conditioning said collecting or refunding means to collect the depositedcoin.

l. In a telephone system, a calling line havingV paystation equipment, an automatic switch in the exchange, a booster battery in the exchange, a called line, a repeater interposed between said calling line and said switch and having means for operating said equipment to collect and refund deposited coins, means for extending a connection from said calling line through said repeater and switch to said called line after a coin has been deposited in said paystation equipment, means in said switch responsive to the answering of the called Yparty tor transmitting an impulse ot current from said booster battery to said repeater, and means in said repeater operated by said boosterbattery current impulse to prepare said repeater to collect the deposited coin responsiveto the breaking ot the established connection.

5. In a telephone system, a calling line, a paystation device connected thereto, a called line, automatic switches at the exchange, a repeater interposed between the calling line and said switches and having means lor controlling said device to collect and refund deposited coins, a control circuit for said repeater, means for operating said repeater and said automatic switches to establish a connection from the calling line to the called line after a coin .has been deposited in said device and to extend said control circuit to the last ol said switches, means in the last ot said switches responsive to the completion ot the established connec tion i'or transmitting an impulse ot boosterbattery current over said control circuit to said repeater, and means in said repeater operated by said impulse Jfor causing said repeater to control said device to collect the deposited coin when said connection is broken.

6. In a telephone system, a calling line, a paystation coin device connected thereto, a paystation repeater, two automatic switches having release trunks, one ot said switches .having means tor transmitting an impulse of booster-battery current over its release trunk responsive to the completion ot a connection established to a called line, means operated by said repeater under control ot said calling line for selecting a desired one of switches, the selected switch then operated by said repeater to connect the calling line to a called line, means in said repeater `for collecting and refunding coins deposited in said coin device responsive to the release of a completed connection, and means in said repeater for conditioning said last'mcans to collect a deposited coin responsive to the reception ot an impulse olf b00ster-battery current when said one switch is the selected switch.

7. In an automatic measured-service telephone system in which selectors and boosterbattery connectors are employed to extend connections between calling paystation lines and called lines after a coin has been deposited in the coin-collecting mechanism at the paystation, a. paystation repeater associated with each selector, said repeater having means tor operating a selector and a connector to establish a connection between a calling paystation line and a called line, means for collecting a deposited coin, and m `ans operated by an impulse ot boosterbattery current from said connector responsive to the completion ot the extended connection lor preparing` said coin-collecting means for operation and operating that means when the connection broken.

8. In a telephone system, a calling line, a paystation device connected thereto, a called line, automatic switches including a boosterbattery connector switch at the exchange, a repeater interposed between the calling line and the automatic switches, a control circuit for said repeater, means for operating said repeater and said switches to establish a connection between said calling line and said called line and to extend said control circuit to .said connector after a coin has been deposited in said device, means in said connector responsive to the completion ot the established connection for transmitting an impulse ol booster-battery current over said control circuit to said repeater, mea-ns in said repeater ttor operating said paystation device to collect a deposited coin, and a relay in said repeater operated by said booster-battery current impulse for preparing said paystation device operating means tor operation and then operatingl it when said connection is broken to collect the deposited coin.

9. In a telephone system, a calling line, a paystation device connected thereto, a. pair ol automatic switches, means whereby the callingline can extend a connection via either switch to a called line after a coin has been deposited in said device, means in one oi' said switches responsive to the answering ot the called party for transmitting an impulse oft booster-battery current, means rendered ettective by the booster-battery impulse to collect the deposited coin upon the termination ot a connection extended via said one switch, said last means elfective to, refund the deposited coin upon the termination ol" a connection extended via the other switch.

10. In a telephone system, a calling line, a

paystation device connected thereto, a first called line for calls to which a charge is made, a second called line for calls to which no charge is made, a pair of automatic switches, means in one of said switches responsive to the answering of a called party for transmitting an impulse of booster-battery current, means whereby the calling line after a coin has been deposited insaid device can extend a connection to said first called line via said one switch or extend a connection to the second called line via the other switch and means effective on the termination of a connection extended to the second called line via said other switch for refunding the deposited coin, said means rendered effective by the booster-.battery impulse to collect the deposited coin upon the termination of a connection extended to the first called line via said one switch.

l1. In a telephone system, a calling pay-` station line having coin-collecting mechanism, a calling subscribers line having a call meter, a manual operators trunk line, all of said lines terminating in the same automatic exchange, a repeater-selector link available to the paystation line, a selector available to said trunk line and said subscribers line, one connector provided with means for reversing the direction of flow of talking current to a calling line responsive to the answering of the called party, another connector provided with means for reversing the fiow of talking current to the calling line and also provided with means for transmitting an impulse of booster-battery current over the release trunk of the calling line responsive to the answering of the called party, means whereby said paystation line can extend a connection by way of saidy repeater-selector link and either one of said connectors after a coin has been deposited in the coin-collecting mechanism, means in said repeater conditions for operation by the boosterbattery impulse when said other connector is employed in the extension of a connection to a called line and operated when said connection is broken to collect the deposited coin and effective when the connection is extended to a called line by said one 'connector and subsequently broken for refunding the deposited coin, means whereby said subscribers line can extend a call by the selector and either one of said connectors, means associated with said meter responsive to the impulse of booster-battery current when said other connector extends the call to a called line for voperating said call meter but ineffective to operate said meter when said one connector extends the call to a called line, and means whereby said operators line can extend a call via the selector and either one of the connectors,

and means associated with the operatorsk line responsive to the reversal of current by either. connector for supervision.

l2.` In a telephone system, a calling line having a coin collector, relay means for conproviding answering trolling said collector to collect and to refund coins deposited therein, an automatic switch, `a called line, means whereby said calling line can associate said relay means with said switch and operate said switch to extend a connection to said called line after a coin has been deposited in said collector, means in said switch for transmitting a booster-battery impulse responsive to the a series of automatic switches including a paystation repeater, means whereby said calling line can extend a connection to said called line via said repeater and switches after a coin has been deposited in said collector, means in saidrepeater for operating said collector to collect and to refund coins, a source of' special current associated with the final switch of said series, means in said final switch responsive to the answering of the called party to momentarily substitute said special current for the regular current of the system in the release trunk conductor of the connection through said switches and repeater, a relay inl said repeater connected to said release conductor and unresponsive to the normal current therein but responsive to said special current therein to condition said collector operating means for its collecting operation, and subscriber controlled means for operating said conditioned means to operate said collector to collect the deposited coin.

14. In a telephone system in which the coin collector of a ,callingy paystation line is controlled to collect a deposited coin by the application of a special current of one polarity thereto and to refund a deposited coin by application of a special current of another polarity thereto, ka paystation repeater having means responsive to the breaking of a connection by the calling line to apply one or the other of said special eurrents to said coin collector to either collect conductor to said repeater, and means in said repeater operated by said impulse to condition said current applying means lo apply the special current of Said one polarity to said collector upon the breaking of the eornpleted connection to collect the deposited com.

In Witness whereof, I hereunto subscribe my name this 13th day of January, A. D.

VICTOR S. THARP.

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