US1830873A - Telephone system - Google Patents

Description

w. T. HAINES TELEPHONE SYSTEM Nov. 10, 1931.

Filed Jan. 15, 1931 2 sheets shef l nwm N MS wve/vroe I W 7: HAINES A TTORNEV -Nov. 10, 1931. w, HAINES 1,830,873

- TELEPHONE SYSTEM Filed Jan. 15, 1931 2 Sheets-Sheet 2 m/vawrox? W T. HAINES ATTORNEY f Patented Nov. 10, 1931 zUNlTED s Es PATENT OFFICE WILLIAM '1. HAINES, o MOUNTAIN LAKES, EW JERSEY, ASSIGNOIB. T AMERICANTT TELEPHONE AND TELEGRAPH ooMPANY, A CORPORATION. on NEW YORK TELEPHONE sYs'rEM Application fi led January 15, 1931. Serial No. 508,973.

This invention relates to telephone systems and particularly to automatic systems involving coin controlled lines.

The objects are to extendthe range of coin-line service in dial areas, to secure a re liable test of the calling line to distinguish coins of different values, to prevent the test circuits at the substation from interfering with the quality of transmission, and to otherwise improve systems of this character.

According to the present practice a calling party at a coin-box'station can establish calls on a purely automatic basis only within certain local areas, such as those for which the rate isa five-cent coin. Ifhe wishes to tend calls, without the assistanceof an 0perator, into zones requiring different toll charges. This is accomplished by aftest ng mechanism at the central oflice whlch makes l two separatetests of the line, one by applying current in one direction and the other by applying current in the opposite direction. The first test operates a polarized relay at the substation to remove a normal ground connection from one of two coin contacts, allowing a test to be made to determine if the other contact has been operated by the deposit of the required coin. The second test operates the polarized relay in such'a way as to remove theground potential from the second contact, allowing a test to be made of the first contact. In this manner the central oiiice mechanism automatically determines whether the coin deposited by the calling party is of a denominationsufiicient to entitle him to obtain the connection for which he has dialed.

A feature oftheinvention is an arrangement in which the control switch of one of the automatic selectors is capable of taking period.

a plurality of .difierentsettings, these settingsvrepresenting respective calls requiring deposits of difierent Values. In its different, settings the control switch causes talking current to be supplied to the calling line in differentmanners for the purpose of removing ground potential at the substation regardless of the denomination of the deposited coin.

This is for the purpose of improving the transmission during the conversational Another feature of the invention is an arrangement whereby a subscriber may obtain a call requiring deposit of a given coin, I

such as afive-cent piece, by using acoin of higher denomination, such as a ten-cent piece.

Since the subscriber dials a number for which a five'rentpiece is sufficient, the control switch of the selector would in its normal operation take up a setting representative of a five-cent call. When, however, the testing mechanism tests the line and discovers that a ten-cent piece has been deposited, it automatically alters the setting of the control switch so that it now takes up a position the same as it would had a ten-cent call been established. This insures that the ground ing the conversational period."

In the drawings accompanying this specification Figurel discloses a portion of an automatic telephone system embodying'the features of the invention, Fig. 2 is a perspec tive View showing the structure of the coin mechanism employed at the substation, Figs. 2-}, l and 5 are details of this structure.

Referring particularly to Fig. 1, the coincontrolled telephone lineylOO is equipped at the substation with the usual receiver 101, talking transmitter 102, and impulse dial 104 for controllingthe selector switches at the central oi'iice. The substation is also provided with a coin box including the operating magnet 227 and coin-operated contacts 214;,

connection at the substation is removed dur- 215, 222, 223 and 224. Also there is provided .a polarized relay 105 which responds to test Kopp Patent mechanism will be described in detail herematter.

The line 100 extends to the central ofiice and terminates in the bank of a line finder switch F, only a portion of which is shown in the drawings. Finder F serves to extend the calling line over the link circuit to a first or district selector switch S, also shown only in part.

The central office is also equipped with register senders which serve to receive impulses representing the wanted designations, including both cities and numerical codes, to control the selective operation of the switches in accordance with the registered designations and to perform the necessary tests of thecalling 11118, to determine whether the proper coin has been deposited, entitling the calling party to the call for which he has dialed and also to signal a monitoring operator in case the coin test proves unsatisfactory. One of these senders is partly illustrated in the drawings,,including a disclosure of only what is necessary to a clear understanding of the invention. These senders are associated with the link circuit ext-ending between the finder F and selector S by means of a selecting switch (not shown) usually called the sender selector. The equipment comprising the register sender is shown in the drawings below and to the right of the broken line. It includes a timing switch TS, a series of ofiice and numerical registers, two

at which, R1 and R2, are illustrated, a conrol switch CS whichcontrols the testing of the calling line to determine the nature of the coin deposited, and a translator switch T, together with numerous relays and other devices. The switches T S, R1, R2 and CS may be of the single-motion step-by-step type well known in the art. Translator T may also be of this type, or it may, it desirable. be a switch of the power. driven type.

The link circuit between the finder F and,

selector S is controlled by a sequence switch 130 having numerous contact springs which are closed in various positions as the switch moves from one position to another. The link also includes a repeating coil RC, the secondary windings of which are divided into sections in order to obtain the necessary transmission characteristics for the particular call concerned.

The line finder-selector unit may employ panel. switches and a circuit arrangement similar to that disclosed in theHenry Patent No. 1,575,336 of March 2, 1926 and in the No. 1,589.402 of June 22, 1926. Certain features having to do with the selection of the repeating coil windings and other control circuits may be of the same general .the contact 215 against the contact 214.

and 224 to remain closed.

a ten-centpiece descends the compartment ation of the circuits, a description will be given of the structure and operation of the coin mechanism shown in Figs. 2, 3, 4 and This mechanism'comprises a hopper or coin receptacle 200 having two compartments 201 and 202 formed bya partition 203. These compartments receive coins of dilferent denominations which have beendirected to the entrance of the receptacle by the coin chute 204 having the runways 205 and 206. For example, coins of one denomination, such as five-cent: pieces, traverse the chute 205 and enter the compartment 201, whereas coins of another denomination such as ten-cent pieces,

descend the chute 206 and enter the other-- compartment 202.

XVithin the compartment 201 is atrip' finger;207 pivoted at7208. This trip finger carries a shoulder 209 which, in its normal position, supports a lever 210 pivoted on the rod 211, thus holding the contact actuating arm 212 against the pressure of spring 213,

permittingthe coin contacts 214 and 215 to remain open. l/Vhen, however, a coin descends the compartment 201, it strikes the finger 207 causing it to rotate about its pivot 208 and permitting the shoulder 209 to move out of engagement with the lever 210. lVith the lever 210 free, the spring 213 immediately causes it to rotate about the rod 211 closing purpose'of these contacts will be explained in connection with the circuit description.

Within the other compartment 202 is a second trip finger 216 pivoted aboutthe rod 217 on the frameof the device. The trip finger 216 also carries a shoulder 218 which, in the normal position, supports the lever 219, pivoted to the rod 211, and holds the contact actuating arm 220 against the pressure of spring 221, permitting coin contacts 222 and 223 to remain open and contacts 222 hen, however.

202, it strikes the trip finger 216 and rotates it about its pivot, causing the shoulder 218 to escape from beneath the lever 219. Thereupon the lever 21 9. is-rotated'by the spring 221 to close contacts 222 and 223 and to open contacts 222 and 224. f

After the coins have operated their respective trip fingers, they land on the usual trap 225 -wl'1erethey"await final. disposal jj either into the-coin till or into the return chute.

The coins'are 'disposedof by means The r Ills.

ofthe usual operating magnets 227, which attract the armature 228 to rotate/the. de-

trip fingers to their normal latched positions.

A detailed description will now be given of the operation of the circuits shown in Fig. 1. uFo'r this purpose itwillfirst be assumed that the calling party wishes to make a .call into a zone for which the charge is five cents and that he deposits a. five-cent piece 1 in the coin box. l/Vhen the receiver 101 is removed frcm its switchhook, a circuit is completed from battery, through the winding of line relay 114, contact of cut-off relay 115, over the ring conductor 113, through the left winding of the induction coil, switchhool: contacts, transmitter 102, winding of the polarized relay 105, normally closed contacts of dial 104, over the tip side of the line 112,

through the contactof relay 115 to ground.

The line relay 114 operates and, in the well known manner, initiates the operation of the line finder F and-a sender selector switch. The finder F finds'the calling line 100, the sender selector chooses an idle sender, and the controlling sequence switch 130 advances into some position where contacts 118 and 119 are closedto extend the tip and'ring con- 'ductors of the calling line over conductors 168 and'169 to the impulse relay v158 of the register sender. I

The subscriber proceeds to manipulate his dial 104 to transmit impulses representing the designation of the wanted-line, causing. the

setting of register's'Rl, R2 and other similar *registers- As soon as the first two digits,

representing theoflice code, are dialed, the

translator Tassumes its position depending upon these digits. Since the calling party has dialed for a zone, for which the charge is five cents, it will'be assumed that the translator T positions its brush 170 on some ter- 'minal other than the terminals 166 and 167. Accordingly, neither of-the relays. 155 and 157 operates. n

Following the seizure of the sender, the time-measure'switch'TS is' caused to m ve from its normal to its first off-normal position, where a circuit is completed from battery, through the winding of relay 154, conductor 171, brush 1620f said switch, conductor 172 and thence to ground over an operated relay 161. The relay- 154 operates, and locks in a circuit frombattery through its winding and left contact, back contact of relay 153 and thence to ground'over conductor 172. With relay 154 operated, a circuit is completed from battery, through the winding'of relay 164, brush 163 of the time measure switch, front contact of relay 154 to the grounded conductor 172. Belay-164 causes the stepping magnet165 to advance the time.-

called line until-relay 154 has released subsequent to a satisfactory coin test.

Following the completion of the dialing operation, the time measure switch TS advances into position 15 where a circuit is closed from battery, through the winding of relay 138,:back contact of relay 177, brush 162 to the grounded conductor 172, Relay 138 in conjunction with interrupter 174 advances the control switch CS through a number of'positions to perform the tests of the calling line to determinewhether the proper coin has been deposited by the calling party. As soon following the energization'of relay 138 as the interrupter 17 4 closes its contacts, a circuit is completed frombattery, through brush 134 in the normal position of the switch,

"contacts of the interrupter 174, front contacts of relay 138. Relay 140 transfers the l tip and ring conductors of the line 100 from the impulse relay 158 and connects them across a test loop including the relay 141 and the differential relay 142.

A test circuit is now traceable from the.

negative source of potential 145, right back contact of relay 144, left winding of relay the stepping magnet 143 of the switch CS and 142, winding of relay 141, left front contact I *of' relay 140, conductor 169, sequence switch spring 119, winding ofrelay 117, right back 111 contact'of relay 116, thence over the ring conductor 113 of the line 100, through the winding of'polarized relay 105and returning over the tip conductor 112, through the left back contact of relay 116, sequence switch spring ii" 118, conductor 168, right front contact of re lay 140, right winding of relay 142 to ground.

Should the line be free from ground con- 'necticns, current will flow through both winding of relay 142 causing it toremain inert 1 It will be 'recalledthe assumption is that a five-cent due to its differential character.

piece has been deposited in: the coin box resulting in the closure of the coin contacts 214 and'215. When negative current is applied to tliering conductor of the line, as above traced, relay moves its armature in such a directionas to open the contacts106, allow- 107. Since, however, the contacts .222 and ingground potential to remain on contacts F attracts its armature.

. from battery, through the winding of register relay 149, brush 136, front contact of relay 141, back contact of relay 142, conductor 176, "front contact of-the magnetic 143, brush 135, right back contact. of relay 139 to grounded conductor 175. Relay 149 operates and locks directly to conductor 175. On the next opening of the interrupter 174, the magnet 143 releases and advances the brushes of switch CS into position 2.

In position 2 a circuit is closed from battery, through the windingof relay 144, brush 135, right back contact of relay 139 to the grounded conductor 175. Relay 144 operates and disconnects the source 145, permitting relay 141 to release. Relay 144 at its right front contacts extends the ring conductor through'the left back contact of relay 1-47 and resistance 148 to ground. This acts as a drain for any electrostatic charges thatare present on the line. Relay 144 locks through its left front contact to the conductor 17 5.-

The next closing and opening of the interrupter 174 causes the advance of the switch CS into position 3. In this position a circuit is completed from battery, through the winding of relay 147, brush 1351 and thence to the grounded conductor 175 as above traced. Relay 147 disconnects the resistance 148 and substitutes the positive source of test potential 146. The test circuit now extends from the source 146, through the left front'contact of relay 147, right front contact of relay 144, thence as above traced, to relays'142 and 141 to the ringrconductor of the line. Since current now flows in the opposite direction, relay 105 attracts its armature in the opposite directionto remove ground potential from the contact 107 and to permit ground potential to remain on contact 106. The circuit is now traceable from ground through the contacts 106, coin contacts 215 and 214 closed bythe deposit of the five-cent piece, contacts 224 and 222, windings of magnet 227 to the tip conductor 112 of the line 100. The coin magnet 227 is not-.operatedin this circuit, but the presence of ground potential on *conductor 112 shunts the right winding of relay 142, and said relay attracts its armature. Relay 141 also operates in series with the left winding of relay 142. When the stepping magnet 143 again closes its contacts, a circuit is completed from battery,through the winding of register relay 152, brush 137, front contact of relay 142, conductor 176, contact of magnet 143 to ground at the right contact of relay 147. Relay 152 operates and locks to the grounded conductor, 17 5.

7 When magnet 143 again deenergizes'; the switch CS steps into position 4 releasing relay 147 to disconnect the source 146fron1 the line. This permits relay 105,141 and 142 to release. With the switch in position 4 and the test completed, a comparison is nowmade between the results oftheatest recordedzon the register relays 149, 150, 151 and 152 and the record established on relaysv 155 andv 157 in accordance with the number dialed bythe subscriber; Since the call is a five-cent one, neither of the relays 155 and 157 has operated. As already explained, relays 149 and 152 have operated as aresult of the test, showing that a five cent piece was deposited by the calling party. Inasmuch as the results of'the'test compare favorably with the number dialed, a circuit will be completed for the relay 153. This circuitmay betraced from battery, through the winding of the relay, outer right back contact ofrelay 157, outer left contact ofrelay. 152, right contact of relay 149, brush 133, .left back contact of relay 139 to the grounded conductor 17.5. Relay 153 operates and releasesrelay 154. Relay 154 on releasing extends the grounded conductor 172 to the conductor 173 causing the operation of relay 177, which acts as a signal to the sender that it may proceed to complete the partially: established connection to the called subscribers line.

The relay 177 in operating causes the release of relay 138, which places ground potential on the remaining terminals associated with brush 132 resulting-in an obvious circuit for operating the stepping magnet 143 to return the brushes of the switch OS to their normal position. Relays 140, 149, 144 and 152-are now deenergized.- 1

'At some convenient timefollowing' the coin test, the district controlling sequence switch 130 is advanced into a talking-selection position depending upon the nature of the'call extended; It will be assumed that fora fivecent call, such as the one now being discussed, the sequence switch 130is driven ninto position 13 where it remains during conversa- 'tion. The positioning of the sequence switch 130 for talking selection is controlled by a circuit which extends from conductor 178, over the right back contact of relay 155, outer left back contact of relay 157, right back contact of relay 156 and thence over a conductor extending to the zero counting relay (not shown) in the sender. In the-mannerfully explained in the above-mentioned patents to Henry, Kopp, and Steam et al., the sequence switch 130 is selectively advanced into talking-selection position 13. In position 13 current is supplied to the calling line from battery, through the .upper'back contact of relay 120, lower'left winding of repeating coil RC, thence over the ring conductor of the line, through the winding of polarized relay 105 in shunt-of the resistance 1-03 and returna grounded conductor 172.-

ing over-the tip conductor, through the upper left winding'of the coil RC, lower back contact of relay 120 to ground. Inthis circuit it will be noted that the negative pole of battery is connected to the ring conductor of the line. This, it will be remembered, causes the relay 105 to move its armature to the left opening contacts 106, thus removing the ground potential from the line during the conversation. Resistance 103 preventsmagnet 105 from interfering with the voice currents. With the district selector sequence switch'130 in position 13, the windings 121 and 123 are included in the calledend of the circuit of the connection. Assuming that the five-cent call has "been extended over trunk 179, the circuit may be traced from the tip conductor of this trunk, over the uppermost brush of selector S, sequence switch spring 128, winding 121 of coil RC, contacts of spring 125 to the winding 'ofrelay 127 lower contact of spring 126, winding 123, spring 129, thence to the ring conductor of the trunk 1 9.

a designation corresponding to a ten-cent zone and deposits therefor a ten-cent piece In this case the" translator -T advances its brush 17 0 to the terminal 167 following the setting of the registers R1 and R2, and a circuit'is closed through the right winding of relay 157. Relay 157 operates and looks through its left winding and contact to the The sender controls the district selector S to seize the trunk 180 leading to a ten-cent zone, the time-measure switch TS is operated in the manner hereinbefore mentioned, and the control switch CS is driven from positions 1, 2 and 3 to perform the coin test.

Since a ten-cent piece is now deposited in the coin box, contacts 222 and 223 are closed, and contacts'222 and 224 are opened, and the five-cent ' contacts 214 and 215 are also open. When the negativesource of'potential 145 is connected to the line for the first part of the test, relay 105 moves its armature to the left removing the ground potential from contact 215 and allowing it to remain on contact 223. Thus, ground potential exists on conductor 1 12, and the differential relay 142 is unbalanced and attracts its armature. With relay 142 operated in position 1 of the control switch, and magnet 143 operated on the second closure of interrupter 174, a circuit iscompleted from battery, through the winding of register relay 150,-brush 137, front contact of relay 142, groundover conductor 176 as above explained. Relay 150 operates and locks to conductor 175. 7 During the second part of the test the positive source of potential 146 is connected to the line, causing relay 105 to move its armature to the right to remove ground potential from the contact 223;- In this case no ground potential occurs Assume. next that the calling party dials on conductor 112, and relay 142 is not. un-

balanced to" attract its armature. Accord ingly, a circuit is completed in position 3 of the control switch from battery, through the winding of relay 151,'-brush 136, front contact of relay 141, back contact of relay 142 to ground over conductor 176. Relay 151 operates and locks to conductor 175. r When the'control switch advances into p0 sition4 as previously explained, a circuit is completed through'the'winding of relay 153, outer right-hand front contacts of relay 157, outer right contact of relay151, left contact of relay 1 50 and thence through the brush 133 to ground. The operation of relay 153 in this circuit indicates that a ten-cent piece has been deposited in payment for the desired call which extends into a ten-cent zone. Belay 153 brings about the completion of the connection as above explained. i

In this case a different settingof thesequence switch 130 is required in order to 7 remove the ground potential from the substation during conversation and to provide a diffei'entjarrangement of the repeating coil RC5 The talking selectioncireuit for this purpose maybe-trace'd over the conductor 178, right back contact of relay 155, outer left front contact of relay 157 and thence to the N o. 1 counting relay. The counting relays cause the positioning of the sequence switch 130 in position 14 rather than in position 13 as in the case of a five-cent call.

lVith the sequence switch-in position 14, an

obvious circuit is closed for relay 120, Relay 120 reverses the direction of current over the calling line duringconversation so that the relay at the substation now moves.

its armature to the right, removing ground potential from the ten-cent contacts and thus preventing this potential from occuring on the conductor112. With the sequence switch 120 in position 14, the called end of the connection may be traced from the tip conductor of trunk 180, through the upper brush of selector S, spring 128, windings 121 and 122, contacts of spring 125, winding of relay 127, contact of spring 126, windings 124 and 123, spring 129, and thence to the other side of the ring conductor of trunk 180. Y Y i It will next be assumed that the subscriber deposits a ten-cent piece in order to secure a connection into a five-cent zone. Having dialed a code representing a five-cent call, neither relay 155 nor 157 will operate. The coin test is made in the manner already ex plained, and, since a ten-cent piece has been deposited, register relays 150 and 151 are ope erated. As soon thereafter as the switch CS reaches position 4, a circuit is completed from battery, through the winding of relay'153, right winding of relay 156, contacts of relays 151 and 150 and thence to ground as above traced. Relay 156 operates, and it locks through its left winding and contact, and

relay 153 operates'to permit the completion of the connection. With relay 156 operated, the talking selection circuit now extends over conductor 17 8, right back contact of relay 155, outer left back contact of relay 157, right front contact of relay 156 and thence to the No. 1 counting relay. This, it will be remembered, is the same circuit that was closed for a call extended into the ten-cent zone. Accordingly the sequence switch assumes position 14 during conversation,'and relay 105 is operated to remove ground potential from the ten-cent contacts, thus preventing this potential from existing on the line during conversation.

Assume next that the subscriber dials for a call into a five-cent zone but fails to deposit any coin. No ground potential occurs on the line 100'during the test, and the differential relay 142 remains inert both when connected in series with source 145and in series with source 146 in positions 1 and 3 respectively of the switch CS. Accordingly, a circuit is closed in position 1 from battery, through the winding of relay 149, brush 136, front contact of relay 141, back contact of relay 142 to ground over conductorlTG. Relay 149 operates and locks as explained. In'position 3 a similar circuit is closed for relay 151. WVith relays 149 and 151 operated no circuit is closed for operating the relay 153; accordingly the sender refuses to complete the extension of the connection to the called line. Instead a circuit is closed from battery, through the lamp 181, conductor 182, inner right back contact of relay 157, front contacts of relays 151 and 149, thence to ground as above traced. The lamp 181 attracts the attention of the monitoring operator, who listens in and instructs the calling party to deposit the necessary coin.

Assume next that the calling party dials for a ten-cent call, but deposits a five-cent piece. Having dialed for a ten-cent call, the translator T sets its brush on terminal 167, and relay 157 operates. During the test, however, relays 149 and 152 are operated as above explained in connection with the es tablishment of a five-cent-call. Therefore, relay 153 fails to operate when the switch CS reaches position 4, and a circuit is completed instead from battery, through the lamp 181, interrupter 183, middle right front contact of relay 157 and thence through contacts of relays 152 and 149 to ground.

Interrupter 183 causes the lamp toflicker as a signal to the operator that a five-cent piece was deposited whereas a ten-cent'call is desired by the calling party.

In a similar manner it will be found that the lamp 181 is caused toflash by means of interrupter 184 should the calling subscriber seek a ten-cent call without depositing any coin. Similarly a false ground potential on the tip conductor causes the light to burn steadily when a five-cent call is attempted and causes the lamp to flash by means of the interrupter 184 when a ten-cent call is attempted. I

Should the calling subscriber abandon the call by replacing the receiver on the switchhook during the test period, the relay 141 releases, and a circuit is completed from battery, throughjthe winding of relay 139, back contact of relay 141, back contact of relay 142, thence over conductor 176 to ground. Relay 139 locks to conductor 17 5 and extends this grounded conductor through itsright front contact to the first,second and third terminals associated with brush 132. This causes the magnet 143 to step the selector immediately into position 4 and the connection is again placed under' control of the impulse relay 158. If the receiver remains on the hook, relay 158 releases and brings about the release of the equipment.

\Vhat is claimed is: 1. In combination, a telephone line having a substation thereon, a coin mechanism at said substation having a pair of contacts, controlled respectively by coins of different denominations, means normally eifective for applying a given electrical condition to both of said contacts, means for-removingsaid condition first from one contact, then restoring it thereto and removing it from the second contact, and means for testing said contacts to determine which one-has been operated by a deposited coin.

2. In combination,a telephone line having a substation thereon, a coin mechanism at the substation having a pair of contacts controlled respectively by coins of different values, a relay at the substation normally effective to apply a given potential toboth of said contacts, means for operating said relay in one manner to remove said potential from one of said contacts, means for operating said relay in another manner for restoring said potential to said first contact and for removing it from the second contact, and-means for testing said contacts over the telephone lineto determine which one of said contacts has been operated by a deposited coin.

3. The combination in atelephone system of a line having a substation thereon equipped with a coin device, said coin device including a pair of contacts controlled respectively by coins of difierent denominations,a polarized relay at the substation nor-. mallyIserving to apply ground potential to both of said contacts, means for connecting a source of potential of one polarity to the line to operate said relay-to remove said ground potential from the first one ofsaid contacts, means for applying a source of potential of opposite-polarity to the line to operate said relay to remove said ground potential from said second contact-and tov restore it to said first contact, and testing means effective to test said contacts to determine which one has been operated by a deposited coin.

4. The combination in a telephone system of a line having a substation thereon equipped with coin receiving mechanism, said mechanism including a pair of coin controlled contacts, automatic switches for extending said line, means controlled from the substation for sending designations to control the operation of said switches, means normally effective for applying a given potential to both of said contacts, means for removing said potential first from one contact, then restoring it thereto and removing from the second contact, means for testing said contacts to determine which one has been operated by a deposited coin, and means responsive to said testing means for enabling the extension of the wanted connection in accordance with the designation transmitted I from the substation.

5. The combination in a telephone system of a line having a substation thereon equipped with a toll device, a connection for applying a potential to said toll device, an automatic switch, means for operating said switch to extend said line in either of two directions, a source of talking current for supplying said line during conversation, means for causing said switch to take up either one of two positions according to the direction in which said line is extended, and means for determining the direction of flow of said talking current according to the position of said switch to cause the disconnection of said source of potential from said toll device.

6. Ina telephone system, a line having a substation thereon equipped with a toll device, a polarized relay for connecting a potential to said device to control the operation thereof, a selector switch, a designation recorder, means for transmitting impulses over said line to record a desired designation on said recorder, means for setting said selector switch under the control of said recorder to one position for a call of one value and to another position for a call of another value, a source of talking current for said line, means effective in one position of the selector for connecting said source to the line in such a direction as to operate said relay to remove said potential from the toll device, and means effective in another position of said selector to reverse the direction of talking current to cause the operation of said polarized relay to remove said potential from the toll device.

7 In a telephone system, a line having a substation thereon, acoin mechanism at said substation arranged to receive coins of two different denominations, means controlled by the deposit of a coin of either denomination for closing a ground connection to said line,

tion, means efiective to permit the establishment of a connection represented by a coin of the lower denomination when a coin of the higher denomination is deposited instead,

and means effective to cause said selector switch to take up the same position it would have taken had the call been one represented by the coin of higher denomination.

In testimony whereof, I have signed my name to this specification this 13th day of January, 1931. I

WILLIAM '1. HAINES.

of talking current

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