US1506735A - Coin-collect system for automatic telephone exchanges - Google Patents

Description

R. D. CONWAY ET AL COIN COLLECT SYSTEM FOR AUTOMATIC TELEPHONE EXCHANGES Filed L 26, 1920 2 Shuts-Shut 1 1 van fora fF a/ph L Qua s5 ififlfififfifi R. D. CONWAY ET AL COIN COLLECT SYSTEM FOR AUTOMATIC TELEPHONE EXCHANGES Filed Aug. 26, 1920 2 Sham-Shem 2 SQW f 3 ww 26 any flw W M P H mv H i W A a QN AND W h w my. QR a W p x \R J JEN l x W vmw fi wmw m Rw H. w U )lolll AM o WEN b m Q 2? hfi [ID QM N u w mww www www g m SN 4 t n NN m m Sept. 2 1924.

a t 3 k Patented Sept. 2, 1924.

UNITED STATES PATENT OFFICE.

ROY D. CONWAY, OF CHATHAM, AND RALPH L. QUASS, OF HAWTHORNE, NEW JERSEY, ASSIGNORS TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK,

N. Y., A CORPORATION OF NEW YORK.

COIN-COLLECT SYSTEM FOR AUTOMATIC TELEPHONE EXCHANGES.

Application filed August 26, 1920.

T all whom it may concern-.-

Be it known that we. ROY D. CONWAY and RALPH L. QUASS, citizens of the United States, residing at Chatham, in the county of Morris and State of New Jersey, and Hawthorne, in the county of Passaic and State of New Jersey, respectively, have invented certain new and useful Improvements in Coin-Collect Systems for Automatio Telephone Exchanges, of which the following is a full, clear, concise, and exact description.

This invention relates to machine switching telephone systems with subscribers control wherein coin collectors are employed at the substations.

Its object is to provide an improved-circuit arrangement for systems of this type which shall be positive and etiicient in operation.

In accordance with one feature of this invention a coin collector having a polarized magnet is provided at the substation and the circuit is so arranged that due .to the replacement of the receiver :by the calling party at the termination of the conversation a source of interrupted current is automatically applied to the calling line from one of two sources of coin current of different polarity at the central office, dependent upon whether the called party had responded or not, and if the deposited coin is released by the polarized magnet, upon receipt of the first impulse, the automatic switches at the central office are restored, but if the coin is not so released, its failure to release prevents such restoration and causes succeeding impulses to be transmitted to the polarized magnet in the coin box.

In the present embodiment of the invention. the coin control circuit equipment is located between two non-numerical switches which extend the calling line to an idle first selector. lVhen the parties hang up the receivers, all the switches beyond the first non-numerical switch are immediately released. their holding circuits being controlled from the connector in the wellknown manner. The first non-numerical switch however is held in its set position by a slow relay held operated in a circuit including the normal contact of a coin current applying relay. This latter relay is inert during conversation and upon Serial No. 406,140.

the restoration of the numerical switches is included in circuit with an interrupter whereby it is intermittently operated to apply collect or refund current to the calling line dependent upon the condition of a shifting relay operated and locked up or not dependent upon the response of the called party. The first impulse of current through the coin current applying relay breaks the circuit through the said slow release relay but before the slow relay can release, a relay in the coin current circuit including the calling line operates and provides a substitute circuit for the said slow relay. The first impulse of coin current operates the polarized magnet at the substation of the calling line which either collects or refunds the coin and in operating opens the connection of its coils to ground. This ground was applied due to the deposit of the coin. The next impulse through the coin current applying relay from the interrupting machine operates it, causing it to close its contacts, but no current flows from the coin current generator to the polar ized magnet in the calling line since this relay as stated has disconnected its coils from ground. Consequently the relay referred to in the coin current circuit does not energize and thus no substitute circuit is provided for the slow relay which thereupon falls back, removing ground from the holding winding of the non-numerical switch which thereupon releases. If the polarized magnet in the coin box had failed to function properly on the first impulse, the coils thereof would be still connected to ground, and the relay in the coin current circuit would have energized to prevent the release of the non-numerical switch. A supervisory lamp is preferably provided where it may be seen by an attendant, which lamp lights while the coin collect circuit is functioning, and the failure of the coin box to function properly would be indicated by the continued illumination of this lamp, In case the apparatus functioned properly it would simply flash once.

Referring to the drawings. Fig. 1 shows a calling line, a line switch and the calling line; and Fig. 2shows a secondary line switch, a first selector and the called line.

The invention will be most readily understood from a detailed description of the operations involved in setting up a connection.

Upon the removal of the receiver at the calling substation, the relay 101 of the primary line switch PLS individual to the calling line is operated over the calling line circult. In attracting its armature it closes a circuit including the pull down winding of the line switch which causes the line switch to seize the preselected trunk by operating the set-of springs in the well known manner, as shown and particularly described for example in Patent No. 1,304,369 to A. J. Ray of May 20,1919. The calling line is now extended to the trunk circuit, whereupon relay L is operated as follows: free pole of battery, contact 104 of relay Y, conductor 105, contact 106 of relay S,'conductor 107, contact 108 of relay N N, resistance 187,

conductors 109, 110, inner right armatureand back contact of relay B, lower armature and back contact of relay A, ring conductor 165 including contacts 162, 163 of the line switch, the telephonic loop at the calling substation, tip conductor 164, including springs 166, 167 of the line switch, upper armature and back contact of relay A, left armature and back contact of relay B, retardation coil 188, relay L, outer left armature and back contact of relay N N to ground. Relay L closes a circuit for the cut-off winding 107 of the line switch to hold the line switch set before the circuit for the pull down winding 102 is opened as the line relay 101 releases.

The circuit for the cut-off winding is as follows: ground, left armature and front contact of relay L, conductor 108, outer right armature and back contact of relay H H, conductor 199, contact 198 of relay N N, conductor 146, release or sleeve conductor 125 springs 112, 113, cut-0E winding 107, free pole of battery.

When the primary line switch PLS operated and closed springs 114, the following circuit was closed to operate the secondary line switch SLS to seize an idle first se ector: grounded sprin 115, spring 114, secondary line switch hol in conductor 116, outer left armature and bac contact of relay H H, conductor 117, conductors 201, 202, pull down coil 20 3 of the secondary line switch, contact 204, conductor 205, slow relay 206, to free pole of battery. The secondary line switch SLS in operating closes a' locking circuit for itself, including its windings 207, 203 in series and contact 208 to grounded holding conductor 201.

Relay L, in attracting its left armature, operates slow to release relay N, which operates relay N N. Relay N N in attracting its outer left armature removes the shunt from about the high resistance 118 for a purpose which will shortly appear, and in attracting its inner left armature it grounds the release conductor over conductor 146 to hold up the primary line switch PLS after rela L releases.

Relay N in attracting its inner right armature at 108 substitutes relay RT for resistance 187 in the calling line circuit. Relay RT is thus connected to the ring side of the calling line.

Relay RT is marginal and will not operate over the line circuit due tothe high resistance 118 and relay L. Resistance 118 is normally short circuited, its short circuit being removed when relay NN operates to iIpcrease the margin of operation of relay The circuit remains in this condition until the calling party inserts a coin in the coin box. The coin box may be of the type shown and described in Patent No. 1,043,219 to O. F. Forsberg issued November 5, 1912. As shown and described in detail in said patent the deposited coin causes the closure of contact 120 to ground the tip side of the line 164 and since the receiver is now removed from its hook, this ground is also connected to the ring-side of the line 165. The application of this ground closes a shunt about relay L and the high resistance 118, whereupon the marginal relay RT operates over the circuit including the ring side of the line 165, the calling substation receiver hook, and the ground closed by contact 120 of the coin box.

Relay RT in operating, energizes relay S over the following circuit: battery, armature and front contact of relay RT, conductor 121, relay S, conductors 122, 123, outer left armature and front contact of relay NN to ground. In attracting its outer left armature, relay S connects holding conductor 116 to conductor 117 independently of the outer left armature and back contact of relay HH. In attracting its middle left armature, relay S provides a direct path to ground through coil 188 from the tip side 164 of the line short circuiting relay L and resistance 118. Relay L releasing opens the .circuit of relay N which is slow to release.

In attracting its inner left armature, relay S connects the impulse relay R to the ring side 165 of the line. In attracting its inner right armature, it removes relay RT from the calling line circuit and locks itself to grounded battery at a normal contact of relay Y and to the grounded sleeve conductor 124. This conductor was grounded when the secondary line switch seized the first selector in the well-known manner. The locking circuit of relay S is as follows: free pole battery, contact 104 of relay Y, conductor 105, inner right armature and front contact of relay S, relay S, conductor 122. grounded sleeve wire 124. In attracting its outer right armature, it operates relay HH and slow relay H. The circuit for relay HH leads over the outer right armature of relay B. Relay H then locks itself over conductors 174, 176, outer right armature and back contact of relay B, conductor 189, to battery at its own armature and front cont-act. Relay HH being connected to conductor 189 is also held up by the armature of relay H.

Relay HH in attracting its inner right armature, connects grounded conductor 148 over conductor 147 to the release conductor 125, leading back to the primary line switch to maintain the cut-off winding 107 thereof energized independently of the ground supplied at the inner left armature of relay NN, which relay releases when slow relay N releases, the circuit of relay N having been opened as relay L was short circuited when relay S operated. The grounded conductor 148 is however extended to the SlQCXG conductor 125 by relay HH before relay N, which is slow, releases.

The calling part-y now operates his sender in accordance with the first digit of the wanted number, and on the return of the sender to its normal position, the following circuit including the impulse relay R is interrupted: free pole battery, relay R, conductor 12G, inner left armature and front contact of relay S, conductors 127, 128, inner right armature and back contactof relay B, lower contact of relay A, the ring side 165 of the line, the substation loop, the tip side 164 of the line, the upper back cont acts of relay A, left armature and back contact of relay ]3, retardation coil 188 to ground at the middle left armature of relay S. Upon the initial operation of relay R, before the sender was operated, it closed at its lower front contact a circuit for slow-tooperate relay D which in operating extended the frontcontact of relay R to energize relay DD which connected the incoming and outgoing ends of the tip and ring conductors together, these conductors including a pair of condensers 129, 130. Upon the first retraction of the armature of impulse relay R, due to the sender interrupting the line, relay DD instantly retracts its armatures, disconnecting the incoming tip and ring conductors from the outgoing tip and ring conductors. Relay D is constructed and arranged so that it will not again attract its armature while the impulse relay armature is vibrating. Relay DD thus remains inert during this period to maintain the condensers disconnected from the outgoing ends of the tip and ring conductors to prevent interference with the character of the impulses by the discharge of the condensers.

Only parts of the switches S and C are shown, since these switches are well known. They may be of the type shown in Reissue Patent No. 13,901, issued April 13, 1915, to F. Newforth, Jr.

Assuming that the selector S and preceding switches have been set and the calling line extended to the connector C, the impulse relay 210 (Fig. 2) of the connector C is operated over the following circuit: free pole of battery, right winding of relay 210, normal contact of relay 211, conductor 233, ring conductor 212, multiple terminal 213 and brush 214 of the selector S, ring conductor 215, contact 216, ring conductor 232, conductor 132 (Fig. 1) contact 133 of relay J, conductor 134, upper armature and front contact of relay R, conductors 135, retarda' t'ion coil 181, polarized relay I tip conductor l39'including contact 140 of relay J, tip conductor 225, contact 226, tip conductor 22?. brush 228, terminal 229 of selector S, tip conductor 230, conductor 231, outer normal contact of relay 211, winding of relay 210 to ground. Relay 219 at its front contact operates slow relay 249, which interposes a break in the circuit of release magnet 241 and grounds'the sleeve wire 245 in the well known manner.

The operations of setting the connector need not be described since they are well known, and form no part of the present invention. The impulse relay R, which is in circuit with the sender at its upper armature and front contact controls the circuit of the connector impulse relay 210.

When the connection has been built up to the called line, the response of the called party operates relay 211 which reverses the flow of current in the tip and ring conductors leading back to the coin collect circuit. Relay 1, which is polarized, thereupon operates, closing the following circuit for relay C to prepare a circuit including the coin collect source CC and the calling line. The circuit for relay G is as follows: free pole of battery, relay C, and its normal upper contact, conductor 142, armature and contact of relay P, conductors 192, 157, 145 to the release conductor 125, which is grounded at the inner right armature of relay HH. Relay C in attracting its armature 155 locks itself to conductor 145. Relay J is also energized over the following circuit due to the operation of relay P: free pole of battery, resistance 184, relay J, conductor 150, armature of relay K. conductor 142, contact and armature of relay P, conductors 192,157. 145, 146. to ground over the path traced for relay C. Relay J locks itself over its armature 152, conductors 151,

157, to grounded conductor 145, as previously, traced. Relay J reverses the connections of the tip and ring conductors 195 and 132 with the tip and ring conductors 139, 134, releasing relay P, for a purpose which will appear later. Relay C in operating, closes the following circuit for relay A: free pole of battery, relay A, conductor 154 uppermost armature and front contact of relay C, to the grounded sleeve conductor 124.

lay 210, outer armature and front contact of relay 1211, conductors 231, 230, terminal 229, brush 22S, conductor 22?, contact 5226, conductor contact 159 of relay J, conductors 13- 166, 161, lower armature and front contact of relay A, contact springs 162, 163, conductor 165, through the substation talking set, conductor 164, springs 166, 167, conductor 161, upper armature andfront contact'of relay A, conductor 168, relay P, conductors 139, 170, armature 169 and front contact of relay J, conductor 182 conductor 232, contact 216, conductor 215, brush Q11, terminal .213, conductor 233, inner armature and front contact of relay 211 left winding of relay 210, to ground. Current is fed to the called line over the windings of relay 211.

When the calling party replaces his receiver, ground is removed from the sleeve conductor 235 by the release of slow relay 240. The release of relay 240 causes the connector and selectors to restore. The removal of this ground also releasesrelay S, which in releasing its outer left armature releases the secondary line switch SLS. Relay S at its outer right armature and back contact also closes a circuit for relay Y as follows: free pole of battery, outer right armature and back contact of relay S, conductor 1T1, relay Y, contact 172 of said relay, conductor 173, inner left armature of relay llH, lower contact of interrupting machine I to ground, when the lower contact is closed by the cam of the machine. Relay Y in operating locks itself to grounded conductor M8 by closing its contact 177.

When the interrupting machine I next closes its upper contact, an impulse of current is delivered to coin current applying relay I over the inner left armature and front contact of relay Y. This relay in attracting its armatures impresses positive current of preferably volts from the collect source C C to the calling line to operate the polarized magnet PR in the coin ho at the calling station to collect the coin.

This circuit is as follows: free pole of source (1 C, conductor 178, lower armature and front contact of relay C, relay 190, conductor 179, left armature and front contact of relay 1 upper armature and back contact of relay A, springs 166, tip conductor 164, contact polarized magnet PR to ground. Relay A releases when ground was removed from the sleeve conductor at the connector. The polarized magnet PR- operates to collect the coin as shown and described in said Patent No. 1,643,219. In operating, magnet PR first locks itself to ground by closing contact 119 and then releases the coin, opening contact 120. Due to the closure of contact 119, the magnet PR remains operated as long as the coin current is applied, as shown and described in detail in said Forsberg patent. If the first impulse from the interrupting machine fails to cause the collection of the coin, additional impulses are sent and the release of the primary line switch is held up in the following manner.

When the relay B operated, in attracting its outer right armature it opened the locking circuit previously traced for slow relay H, but before the relay H can deenergize, a substitute circuit is closed by the armature of relay 190 which operates in the coin current circuit, in series with polarized magnet PR. Relay H as pointed out holds up relay H H which at its inner right armature is maintaining ground on the sleeve conductor leading to the holding winding 107 of the primary line switch. Thus these two alternate circuits maintain relay H operated until the ground at the substation is removed. As long as relay Y remains operated, lamp lights before an attendant, who will investigate in case the apparatus does not function properly.

Assuming, as in the normal case, that the polarized magnet PR functions properly, the second time the relay B operates fro-m interrupter I no ground will be present at the substation and the relay will fail to operate and the substitute circuit for relay H at the front contact of relay 190 will not be present wvhen relay B opens the other circuit at its outer right armature and back contact when it is next operated from interrupter I. Relay H accordingly releases, releasing relay HH. Relay HH in retracting its inner right armature removes ground from the sleeve conductor leading to the holding winding 107 of the line switch, resulting in the release of the same.

In case the called party has not responded, polarized relay P would not have shifted its armature and-relay C would have remained inert. At its lower arma ture, this relay would have connected negative current from the 110 volt coin return source CR to the calling line to cause the polarized magnet PR 'to refund the coin, whereupon contact 120 is opened and the magnet locks itself to ground at contact 196. When the operating current ceases, magnet PR releases, opening contact 196,

these calls to prevent short-circuiting the voice currents.

Upon disconnection in this class of calls, inasmuch as relay C is not operated, the coin is refunded as 1n the case of unsuccessful calls.

Resistance 182 is connected to ground at one end and to the condensers 129, 130 at the other end over normal contacts of relay DD. The other terminals of these condensers are connected over normal contacts of relay A to the armatures of relay B over which the relatively high potential coin current flows. This arrangement is for preventing the burning of the contacts of relay B when the high voltage coin current is cut off by the interrupter I releasing relay B.

The ground applied by the polarized magnet PR is connected to the tip side 164 of the line and the ground through the relay 210 at the connector is also normally applied to the same side of the line. However, when the relay 211 is operated when the called party answers, battery is connected to the tip side of the line and to prevent this change from affecting the release operation, relay J which operates due to relay P operating, is provided to restore the original connections. More specifically when the calling party is the first to restore his receiver, inasmuch as relay J is held up from ground on conductor 125, no circuit is closed through the right winding of relay 210, the tip side of the line and coin ground and thus prevent release by holding up relay 210. Relay 210 therefore releases, opening the circuit of the usual slow relay 240. The release of the slow relay energizes the release magnet 241 which releases the connector and the release of this slow relay removes ground from the sleeve conductor 235, which releases the selectors. The selectors release before the coin collecting operations are completed and inasmuch as the ground on the release wire 125, to which relay J is locked, cannot be removed until these operations are completed the circuit referred to from the ground in the coin box to the right winding of relay 210 is not closed.

\Vhen the called party restores first, relay 211 releases and reverses the current flow in the calling line. In this event relays J and K cooperate to prevent this condition from preventing releasa When the relay J operated upon the response of the called party, it caused rela P to restore and closed a circuit for relay 1x by attracting its armature 183 this circuit including the grounded sleevev wire 125. Relay K at its right armature prepares a circuit to shunt relay J. When the called party replaces his receiver and reverses the current flow in the calling line, relay P operates and shunts out relay J over resistance 184, conductor 185, armature and front contact of relay K, contact of relay P, conductors 192, 157, 145, 146, 147, inner right armature of relay H H to grounded conductor 148. Relay P releases before relay K closes its back contact thus preventing relay J from again operating. Relay J restores the original connections to the tip and ring conductors so that the ground in the coin box is now connected to the tip side 164 of the line to which the grounded side of relay 210 is connected. Thus when the calling party restores his receiver, no circuit could be maintained closed from the coin ground to the winding of relay 210 to which the free pole of battery is connected. Thus release is not prevented.

Relay P is located in the tip side of the line rather than the ring side so that if the called party hangs up immediately after the calling party and. releases relay 211 thus reversing battery to the calling party before the slow relay in the connector has time to release and remove the ground from the sleeve wire which is holding up relay '8, relay P will be operated when relay 211 releases over a circuit from the free pole of battery through right winding of relay 210 to the coin ground, thus shortcircuiting relay J as described, which reconnects the coin ground to the grounded side of relay 210 and reconnects the side of relay 210 connected to the free pole of battery to the ring side of the line which is open at the switchhook. Thus release is not interfered with.

Certain levels of the selectors or a preceding selector may contain trunks leading to operators positions, such as information or toll o erators. The induction coil 186 is provide to give such operators a tbne to inform them of the character of the line. As shown in British Patent No. 15,133 of 1911, tone from the source CT in the primary of the induction coil 195 is induced in the secondary 197 of this coil and is transmitted by coil 186 to the sleeve wires 124, 235, 237 and thence to the operators head set, as shown and described in said patent.

What is claimed is:

1. In a machine switching telephone exchange system, the combination of calling and called telephone lines, automatic switches for interconnecting the same, a coin collector at the calling substation having a magnet, sources of interrupted current at the central oflice of different character for operating said magnet either to refund or collect a deposited coin,means controlled by the called party for selecting the source to be connected to the callin line to selectively operate said magnet, and means automatically actuated by the replacement of the receiver by the calling party for applying current from the selected. source to the calling line and for maintaining said source connected to said line until the coin is refunded or collected.

2. In a machine switching telephone exchange system, the combination of calling and called telephone lines, numerical and non-numerical switches for interconnecting the same, a coin collector at the calling station having a magnet, sources of current at the central office of different character for operating said magnet either to refund or collect a deposited coin, means controlled by the response of the called party to prepaie a circuit including one of said sources and said magnet to selectively actuate the same, means actuated by the calling party in replacing his receiver for automatically closing said prepared circuit and for releasing the numerical switches without releasing the first non-numerical switch, and means actuated by the release of the coin for releasing said non-numerical switch.

3. In a machine switching telephone exchange system, the combination of calling and called telephone lines, automatic switches including a non-numerical switch for interconnecting the same, a coin collector at the calling station having a polarized magnet, sources of current at the central oflice of opposite polarity for operating said magnet either to refund or collect a deposited coin, means controlled by the response of the called party to prepare a circuit including one of said sources and said magnet to selectively actuate the same, and means for automatically releasing the numerical switches when the calling party restores his receiver, for holding in its set condition the nonnumerical switch, and for closing said prepared circuit.

4. In a machine switching telephone exchange system, the combination of calling and called telephone lines, automatic switches including a non-numerical switch for interconnecting the same, a coin collector at the calling station having a polarized magnet, sources of current at the central office of opposite polarity for operating said magnet either to refund or collect a coin in said collector, means controlled by the response of the called party to prepare a circuit including one of said sources and said magnet to selectively actuate the same, means for automatically releasing the numerical switches when the calling party restores his receiver, for holding in its set condition the non-numerical switch, and for closing said prepared circuit, and means actuated by the response of said magnet and disposal of the coin for releasing said non-numerical switch.

5. In a machine switching telephone exchange system, the combination of calling and called telephone lines, automatic switches including a non-numerical switch for interconnecting the same, a coin collector at the calling station having a polarized magnet, sources of current at the central office of opposite polarity for operating said magnet either to refund or collect a deposited coin, means controlled by the response of the called party to prepare a circuit including one of said sources and said magnet to selectively actuate the same, means for automatically releasing the numerical switches when the calling party restores his receiver, for holding in its set condition the non-numerical switch, and for closing said prepared circuit, means actuated by the response of said magnet and disposal of the coin for releasing said nonnumerical switch, and means actuated by the failure of said magnet to dispose of the coin, for holding said non-numerical switch set. and for again closing said prepared circuit.

6. In a machine switching telephone exchange svstem, the combination of calling and called telephone lines, automatic switches including a non-numerical switch for interconnecting the same, a coin collector at the calling station having a polarized magnet therein, sources of current at the central office of opposite polarity for operating said magnet either to refund or collect a coin in said collector. means controlled by the response of the called party toprepare a circuit including one of said sources and said magnet to selectively actuate the same, means for automatically releasing the numerical switches when the calling party restores his receiver, for holding in its set condition the non-numerical switch, and for closing said prepared circuit, means actuated by the response of said magnet and disposal of the coin for releasing said non-numerical switch, means actuated by the failare of said magnet to dispose of the coin, for holding said non-numerical switch set, and for again closing said prepared circuit, and a device at the central office adapted upon the repeated closing of said prepared circuit to signal an attendant of the failure of the coin collector to properly function.

7. In a machine switching telephone system, the combination of calling and called lines, automatic switches for interconnecting the same, a coin collector at the calling station having a polarized magnet, sources of current of opposite polarity at the central ollice, and means controlled by the response of the called party to prepare a circuit to transmit an impulse from one of said sources to the calling line to operate said magnet to collect the coin and if the coin is not collected, to automatically transmit succeeding impulses, and means for closing said circuit upon the breaking down of the con nection.

8. In a machine switching telephone system, the combination of calling and called lines, automatic switches for interconnecting the same, a coin collector at the calling station having a polarized magnet, sources of current of opposite polarity at the central otfice intermediate a pair of said switches, and means controlled by the re sponse of the called party and actuated by the replacement of the receiver by one of the parties, for transmitting an impulse from one of said sources to the calling line over a switch at the incoming end to operate said magnet to collect or refund the coin, and if the coin is not deposited, automatically to transmit succeeding impulses, and means actuated by the release of the coin to cause the release of the last named switch.

9. In a machine switching telephone exchange system, the combination of calling and called lines, connecting circuits including automatic switches for interconnecting the same, a coin collector at the calling station having a polarized magnet, sources of current of opposite polarity at the central ofiice, means actuated by the deposit of a coin for connecting said magnet in a grounded branch from one side of the line, means controlled by the response of the called party and actuated by the replacement of the calling partys receiver for transmitting an impulse from one of said sources to the calling line to operate said magnet to collect the coin, said means operating to transmit an impulse from the other source upon the replacement of the calling partys receiver if the called party has not responded, means controlled by the release of the coin for opening said grounded branch, said branch remaining closed if the coin is not released whereby succeeding impulses are transmitted to said magnet, and means actuated upon the release of the coin and removal of said grounded branch for disconnecting the calling line from the connecting circuit.

10. In a machine switching telephone exchange system, the combination of calling and called telephone lines. automatic switches for interconnecting the same, a sender at the calling station for setting said switches, a coin collector at the calling substation having a polarized magnet, sources of current of opposite polarity at the central oflice. means actuated by the response of the called party for preparing a circuit including one of said sources and the calling line, said means remaining inert if the called party does not respond, and preparing a circuit includingthe other source and the calling line, and means automatically actuated subsequent to the response of the called subscriber for closing the prepared circuit to transmit an impulse from one of said sources to collect or refund a deposited coin, and means actuated as long as the coin is held for transmitting additional impulses to said polarized magnet.

11. In a machine switching telephone exchange system, the combination of calling and called telephone lines, automatic switches for interconnecting the same, a coin collector at the calling substation having a polarized magnet, sources of current of opposite polarity at the central ofiice, means actuated by the response of the called party for preparing a circuit including one of said sources and the calling line, said means remaining inert if a called party does not respond and preparing a circuit including the other source and the calling line, means automatically operated upon the replacement of the receiver by the calling party for closing the prepared circuit to transmit an impulse to collect or refund adeposited coin, and means actuated in case the coin is held for transmitting additional impulses to said polarized magnet.

12. In a machine switching telephone exchange systennthe combination of calling and called telephone lines, automatic switches for interconnecting the same, a coin collector at the calling substation having a polarized magnet, sources of current of opposite polarity at the central office, a relay operated upon the response of the called party to prepare a circuit including one of said sources and the calling line, said relay remaining inert if the called party does not respond, and preparing a circuit including the other source and the calling line, a source of interrupted current, a relay controlling a break in said prepared circuit, and a circuit including said interrupted source and latter relay closed subsequent to the response of the called party, whereby said relay closes said prepared circuit to intermittently connect the selected source to the calling line to cause said magnet to collect or refund a deposited coin.

13. In a machine snitching telephone-exchange system, the combination of calling and called telephone lines. automatic switches for interconnecting the same, a coin collector at the calling substation having a polarized magnet. means controlled by a deposited coin for connecting said polarized magnet to ground, sources of current of opposite polarity at the central oilice, a transfer relay operated upon the response of the called party to prepare a circuit including one of said sources and the calling line, said transfer relay remaining inert if the called party does not respond and preparing a circuit including the other source and the calling line, an interrupter I, a slow release relay H for one of said automatic switches P L S, a circuit therefor controlled by the calling party, a pick-up relay Y, a circuit including said interrupter and pick-up relay Y closed upon the hanging up of the receiver by the calling party, a current applying relay B, a circuit therefor closed by said interrupter and pick-up relay Y to cause said current applying relay B to close the prepared circuit, said circuit for said release relay H including a back contact of said current applying relay B, a release control relay 190 in the prepared circuit, an alternative circuit for release relay H closed by release control relay 190 upon its energization, whereby when said prepared circuit is closed to operate said polarized magnet at the substation to collect or refund a deposited coin, said polarized magnet in responding disconnects itself from ground and upon the subsequent energization of release relay B, the said automatic switch PLS is released due to the deenergized condition of release control relay 190. v

14. In a machine switching telephone system, the combination of calling and called lines, automatic switches for interconnecting the same, a coin collector at the calling station having a coin disposal magnet, sources of current of different character at the central ofiice, means controlled by the response of the called party to prepare a circuit to transmit an impulse from one of said sources to the calling line to operate said magnet to collect the coin, and if the coin is not collected, to automatically transmit succeeding impulses, and means for closing said circuit upon the breaking doWn of the connection.

15. In a machine switching telephone system, the combination of calling and called lines, automatic switches for interconnecting the same, a coin collector at the calling station having a coin disposal magnet, sources of. current of different character at the central oflice intermediate a pair of said switches, and means controlled by the response of the called party and actuated by the replacement of the receiver by one of the parties to release certain of said switches and for transmitting an impulse from one of said sources to the calling line over an automatic switch at the incoming end to operate said magnet to collect or refund the coin, and if the coin is not deposited, automatically to transmit additional impulses, and means actuated by the disposal of the coin to cause the release of the last named automatic switch.

In witness whereof, we hereunto subscribe our names this 17th day of August A. D.

ROY D. CONWAY. RALPH L. QUASS.

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