US1722351A - Telephone system - Google Patents

Description

July 3o, 1929. 'R L. QuAs's TELEHoNE SYSTEM Filed ct. ze, 1927 3 Sheets-Sheet 1 July 30, 1929. R. L'. QuAss TELEPHONE SYSTEM Filed Oct. 26, 1927 3 Sheets-Sheet 2 /NVE/WOH.' RALPH L. Qz/Ass July 30, .1929. R. l.. QuAss v TELEPHNE SYSTEM Filed om. 2,6, 192% 3 Sheets-Sheet 5 /Nl/ENTOR.' RALPH L. QUA 5.5

Cfr

Patented .lilly 3G, 1929.

E F HCE RALPH L. QUASS, OF HAWTHORNE, NEW JERSEY, ASSIG-NOR TO "WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE SYSTEM.

Application filed Getober 26, 1927. Serial No. 228,710.

This invention relates to telephone systems and particularly to improvements in trunking circuits.

The object is to simplify the equipment and to increase the reliability of operation in a tol trunking system serving coin lines.

In the past it has been the practice for the toll operator to collect, by means 'of a key, the coin deposited by the calling subscriber in his coin box to enable him to dial for the toll connection.

According to the present invention, this system has been simplified and rendered more reliable by eliminating the manual collection of the coin and providing a means responsive when the toll operator answers a call over a trunk, 'for automatically refunding the coin. This means may consist ot an interrupter, and a relay control arrangement operated when the toll operator answers the call for applying an impulse of, for example, 110 volt negative direct current from the trunk over the tip and ring conductors of the established connection to the calling subscribers station for the operation of the coin box magnet to refund the coin. This impulse may be applied for example, for period of one-half of a second to insure the proper response of the coin box magnet.

'The invention has been illustrated in the accompanying drawings in which Fig. 1 shows a trunk at an automatic ofiice arranged in accordance with this invention, a coin box subscribers station, and intervening automatic switches in diagrammatic form for seizing the trunk; Fig. 2 shows the incoming end of this trunk terminating in a jack at a toll operator-s position. A portion of a toll operators cord is also shown in this iigure. Fig. 3 shows a modified arrangement of the invention in which certain portions of the equipment are common to a plurality of trunk circuits.

A description will first be made of the functions of the circuit arrangement shown in Figs. 1 and 2 Afollowed by a description ot the modified arrangement shown in Fig. 3. A call may be established from the calling coin box subscribers station A through switches at an automatic oiiice B and trunk T to the toll operators position C, and similarly from the calling' coin box subscribers .station D through switches at an automatic office E and the modiied trunk F to the toll operators position C. It should be understood apparatus at the toll operators position C has been shown, except the answering plug of an ordinary cord circuit, as this equipment forms no part of the invention and is not essential for the description thereof.

Assuming then .that the subscriber at sta tion A has deposited a coin to close a `connection to ground for the coin box magnet 8st to enable him to operate dial l35; that he has dialed a certain code number to secure a connection to a toll operator and that the brushes of switch S have justseized the terminals 2 of the trunk T, the first effect of this seizure will, vas is well known in the art, be the energization of relay 4. The circuitor this relay may be traced from battery, winding of relay 1l, lower left hand winding of repeating coil .5, lower outer armature and back contact of relay 6, lower malte-beforebreak contacts of relay 7,- ring terminal of the group of vterminals2 and the corresponding brushesoif switches S and LF through the subscribers loop back over the tip brushes oi' switches S and LF, `tip terminal V.of the group 2, upper outer armatures and back contacts of relays 7 and 6, upper left hand winding o repeating coil 5 to ground at the inner right hand armature and back contact of relay 8. The operation off relay closes an obvious circuit for the operation of relay 10 to close acircuit for relay llas follows: battery, winding of relay 11, right hand armature and back contact of relay 12, lower inner armature and front contact .of relay 10 to ground. Relay 11 in operating closes a circuit from ground through the lefthand windings of repeating coil 14 to the sleeve terminal of the group 2 to hold the preceding selector in actuated position.

The operation of relay 11 also closes an obvious circuit for' the operation of relay 1G. This relay in operating closes a circuit for the transmission of a ringing tone for the calling subscriber from source 17k over a circuit as follows: tone source 17, outer right hand armature and back contact ot relay 18, condenser 19, outer leit hand armature and front contact of relay 16 to the ring` conductor of the trunk through the subscribers line loop and back to the tip conductor to groundV at the inner right hand armature and bach contact of relay 8. This tone indicates to the calling subscriber that the toll operator is being signalled.

" Relay 16 connects at its right hand arinature and inner left hand armature and 'l'ront contacts, ground and battery through the windings of relay 12 and the right hand windings of repeating coil 5 through upper armature and lower outer armature and front contacts of relay 10 to the tip and ring conductors of trunl: T through the winding vof the polarized relay 101 and the high resistance 102. This circuit causes the operation of the polarized relay 101 which in turn closes an obvious circuit for the operation of relay 103. This relay in operating its lower armature closes a circuit for the light,- ing of lamp 104; this circuit being completed through the left hand armature .and back contact of relay 105. Lamp 104C lights to indicate to the toll operator that a connection is desired over this trunk.

The toll operator answers this call by inserting the plug 107 of an ordinary standard toll cord into jack 108. A circuit is thereby established over the sleeve terminals of plug 107 and jack 108 i'or the operation of relay 105. Relay 105 in operating opens the circuit for lamp 104 which is thereby extinguished. Relay 105 also closes an obvious circuit for the operation or relay 110. This relay closes at its armature and front contact a Vlow resistance bridge across the tip and ring conductors of trunlr T by shunting the high resistance 102. Due to this low resistance bridge relay 12 will now operate to close a circuit for slow releasing relay 20 as follows: battery, winding of relay 20, outer left hand armature and `front contact of relay 12 to ground at the armature and front contact of relay 11. Relay 20 closes a circuit for the operation ot' relay 18 as follows: battery, right hand winding of relay 18, armature and front contact of relay 20, left hand armature and back contact of relay 22, inner left hand armature and front Contact of relay 12 to ground. Relay 18 in operating provides a locking circuit for itself, as follows: battery, lett and hand winding of relay 18, inner lett hand armature and front contact of this relay, make-beforebreak cont-acts of relay 23, armature and front contact of relay 11 to ground. Relay 18 by opening the connection at its outer right hand armature and back contact removes the tone for the calling subscriber supplied'from the tone source 17. This relay also provides a holding circuit for relay 11 by establishing a connection to ground through its inner right hand armature and .front contact. This is for the purpose of holding this relay operated and the preceding switches busy as long as the toll operators cord is connected to the trunk.

Relay 18 in operating closes a circuit for the operation or relay 8 as follows: battery, winding of relay 8, outer right hand armature and back Contact of relay 23, outer left hand armature and iront Contact oi relay 18 to ground. obvious circuit igor the operation of relay 7. This relay in operating closes a locking circuit iior itself through its winding, and inner lower armature and iront contact to ground at the armature and front contact ot relay 11. Relay 8 in operating removes the direct connection to ground at its inner right hand armature and back contact for the tip conductor of the trunk through the upper left hand winding of repeating coil 5 to the calling subscribers line and a connection from the tip conductor will now pass through re-v sistance 25 to ground. This is to reduce the amount o1" click to the calling subscriber when relay 7 operates to reverse battery. Relay 7 in operating reverses the connec tions from battery through the winding of reiay l and from ground through the resistance 25 'for the subscribers lines to el'fect certain operations in the switches between the calling subscriber and the trunk which are of no importance in connection with this invention and need not be described here.

The operation oi the relays 8 and 7 closes circuits for 'the automatic return of the coin deposited by the subscriber to enable him to call. Tt the interruptcr 27 is closed to ground at the time ot the operation of these relays, relay 28 will be operated over a circuit as follows: From battery, through resistance 29, left hand armature and front contact ott relay 8, winding of relay 28 to interrupter 27 to ground. Relay 28 in operating closes a shunting circuit for relay 30 so that this relay cannot operate at this time. This shunting circuit maybe traced from battery through resistance 8l, front contacts or' the inner upper armature ot' relay 7, outer lett hand armature and back contact of relay 28, right hand armature and front contact of relay 28 to ground. The circuit for relay 30 that is shunted by the above mentioned circuit may be traced t'roin battery through the resistance 31, inner upper armature and front contacts of relay 7, winding of relay 30 to ground at the outer left hand armature and front contact of relay 18. The interrupter 27 may be arranged s0 that it will close a connection to ground every other half second and maintain it closed for one-halt of a second each period.

On the V:lirst opening ot a connection to ground by the interrupter after the operation ot relays8 and 7, the shunting circuit for Relay 8 in operating closes an p relay is opened due tothe release of relay 28 and relay 30 operates. y The operation of relay 30 closes a circuit for relay 32 as fol-V lows: battery, left hand winding of relay 32, right hand armature and front contact of relay 30, inner left hand armature and baclr contact of relay 33, makebefore-break contacts of relay 23 to ground at the armature and front contact of relay 11. Relay 32 in operating provides a locking circuit for itself as follows: from battery through the right hand armature and front Contact of relay 32 and its right hand winding to ground at the outer left hand armature and 'iront Contact of relay 18.

i the outer left hand armature and front contact of relay 18. Relay 33 provides a locking circuit for itself from battery through its winding and inner left hand armature and front contact, through the make-beforebreak contacts of relay 23 to ground at the armature and front contact of relay 11. Relay 33 in operating closes a circuit for the operation of relay 6 from battery through ,A the winding of this relay, outer right hand armature and front Contact of relay 33 to ground. Relay 6 in operating opens the connection to battery and ground from the calling subscribers line and thus causes the release of relay l but relay 1() is maintained operated by the ground supply at the lower inner arma-ture and front contact of relay 6. A'connection. is now established from a 110 volt negative current source through the outer left-hand armature and front contact of relay 32 and the outer upper and lower armatures and fro-nt contacts of relay 6 to the tip and ring conductors leading to the calling subscribers line. Current from this ,c source will now operate the coin boX magnet 341 the subscribes station to refund the coin which he had deposited to enable him to dial. The coin magnet 34 finds a discharge surge path to ground through the resistance and condenser unit 36 to ground at the mid dle Uli right hand armature and front contact of relay 33. This current fromthe 110 volt negative source is applied to the coin magnet 34e for one-half of a second, that is, as long as relay 30 remains released. co

This period is sufhcient to permit the coin magnet 34 to operate and refund the coin.v

shunted to cause this relay to release. The shunting circuit may be traced from battery through the inner right hand armature and front Contact of relay 33, left hand armature and front contact of relay 30, to ground at the outer left hand armature and front contact of relay 18. lien relay 32 therefore releases the connection from the 110 volt negative current ,source is opened at the outer `left armature and front contact of this relay and the coin magnet 34 is released.

i/Vhen the ground is again app-lied through interrupter 27 relay 28 is operated and relay 30 is released, and relay 23 is operated over a circuit as follows: from battery through the winding of relay 23, outer left hand armature and front contact of relay33, inner left hand armature and back contact of relay 32, left hand armature and back contact of relay 30 to ground at the outer left hand armature and back contact of relay 18. Relay 23 provides a locking circuit for itself from battery through its winding, inner right hand armature and front contact to ground at the 4armature and front contact of relay 11,. The operation of relay 23 opens the shunting circuit for relay 30 at its outer left hand armature and back contact and opens at its inale-before-break contacts the locking circuit for relay 33 which is now released. lt also opens the circuitfor relay 8 at its outer right hand armature and back Contact so that this relay will also release and establish a connection to ground. for the tip .conductor of the trunk, in place of the connection through resistance 25. The purpose of this direct connection to ground is of no importance in connection wit-hthis invention and need not therefore be further described. The operation of relay 23 also opens the locking circuit for relay 18 at the make-before-break cont-acts but relay 18 is maintained operated thinugh its original energizing circuit under cont-rol of relay 12 hereinbefore described.

This trunk is also arranged to pass socalled class of service tones to the toll' operator. These tones may be applied on the sleeveconductor of the selector S 'through the left hand windings of repeating coil 14, which Aare connected to ground at the armacondenser of repeating coil 14, inner ,left

hand armature and front contact of relay 23, inner right hand armature an'd back contact of relay 22to the ring conductor of trunk T. The` class of service. tones are.

eil

therefore vrepeated through coil 14, to the toll operators cord connected to jack 108.

The toll operator may remove the class of service tone from the trunk by operating the tone removal key 111. The operation of this key closes an obvious circuit for the operation of relay 112 and this relay in operating` places a short-circuit for the high resistance 102 in the bridge across the tip and ring conductors'. Relay 112 inY operating also opens the circuitfor the release of relay 110. Relay 110 in releasing opens the original short-circuit for resistance 102; the short circuit now being maintained by relay 112. On the release of key 111 relay 112 is released to open the short circuit across the resistance 102 and again closes the circuit for the operation of relay 110. Relay 110 is slow in operi ating so that the short circuit across resistance 102 will be delayed for the period it takesthis relay to operate. Hence the resitance 102 willbe bridged across the tip and ring conductor for a short period due to the operation and release of key 111.

This temporary application of a high resistance bridge across the tip and ring` conductors causes a momentary release of relay 12. Relay 12 in releasing removes the shunt circuit for relay 22 established at the inner left hand armature and front Contact of relay 12 so that relay 22 will now operate in series with the relay 18 in a circuit, from battery through the right hand winding of relay 18, armature and front contact of relay 20, winding of relay 22 to ground at the armature and front contact of relay 11. Relay 20 is slow in releasing so that it will be maintained operated during the release of relay 12 and consequently relays 18 and 22 will be maintained operated through the circuit at its armature and front contact. When relay 12 is again operated the circuit for relay 20 is reestablished at the outer left hand armature and front Contact. The operation of relay 22 opens the circuit from the right hand windings of repeating coil 14 across the tipv and ring conductors of trunk T and thus the class of service tone is removed from the trunk. The operation of relay 22 and the operation of relay 12 closes a connection direct to ground for the sleeve and thereby shunts the primary windings of repeating coil 14 which as noted are connected to ground at the armature and front contact of relay 11.

A connection between the calling subscriber and the toll operator is now completed, with the talking battery and ground now supplied for the calling subscriber through the winding of relay 4 and at the inner right hand armature and back vcon-` tact of relay 8. The calling subscriber may now give the number of the wanted subscriber to the toll operator and as is well known in the art, the toll operator may establish the connection to the wanted ksubscriber. Conversation between the calling subscriber and the called subscriber may then begin as soon as the calling'subscriberl has deposited the required coins in payment Vfor the call. Y y

The toll operator instructs the calling subscriber to deposit the proper amount and arrangementsv are made in the usual manner for refunding or collecting the deposited coins. The usual procedure would be for the toll operator to dial the trunk T over which this connection has been completed and control through suitable means such contact-s as 38, 39 and 40. This arrangement forms no lpart of this invention and will not be further magnet 34. 1f 110 volt negative current is appliedv the coins are refunded,` while the application of 110 volt positive current is for the purpose of collecting the coins. Contact 37 is also operated to transmit a low or high tone over the tip conductor to the toll operator through conductor 42 and upper inner armature and front cont-act of relay 6,*to indicate that the refunding or collecting of the coins has been successfully performed. Vhen the contact 38 opens the circuit for relay 41 this relay and relay 6 release and as both of these relays are slow in releasing sufficient time is provided for the coin magnet 34 to function.

1f supervision is desired from the calling subscriber the manipulation ofA his switchhook will alternately cause the release and operation of relay 4. Relay 4 in releasing releases relay 10. Relay 10 in releasing reverses the battery and ground connection through relay 12 for the tip and ring conductors of trunk T and the polarized relay 101 is thereby released to cause the release of relay 103. Relay 103 applies battery and ground through its armatures and back contacts to the tip and ring conductors leading to the toll operators cord and thereby cause the supervisory lamp in this cord to be correspondingly actuated as is well known in the art. y

, The connection is held established as long as relay 12 is maintained operated. When the calling subscriber releases relay 4 by hanging up his receiver, relay 10 is releasedV to caus-e the release of relays 101 and 103 to signal the toll operator that a disconnection is desired. When the toll operator now removes the toll cord plug 107 from jack 108 relay 105 is released causing the release of relay 110 so that the'high resistance 102 is then bridged across the tip and ring conductors of trunk T causing the release of relay 12. Relay 12 in releasing causes the release of relay 20. Relay in releasing causes release of relay 18 and relay 22. Relay 18 in releasing causes the release of relay 11. Relay 11 in releasing causes the release of relays 23, 7 and 30 and ground is removed from the sleeve conductor so that the preceding switches are restored to normal.

Tf it is now assumed that the subscriber at station D has deposited a coin to close a connection to ground for the coin box 234 to enable him to operate dial 235; that he has dialed a certain'code number to secure a connection to a toll operator and that the brushes of switch S have seized the terminals 202 of trunk F, the first effect of this seizure will be the energization of relay 204. The circuit for this relay may be traced from battery, winding of relay 204, lower left hand winding of repeating coil 205, lower outer armature and back contact of relay 206, ring terminal of the group of terminals 202 and the corresponding brushes of switches b and LF', through the subscribers loop, back over the tip brushes of switches LF and S, tip terminal of the group 202, upper outer armature and back contact of relay 206, upper left hand winding of repeating coil 205 to ground. The operation of relay 204 closes an obvious circuit for relay 210 which in turn closes a circuit for the operation of relay 211 as follows: battery, winding of relay 211, right lhand armature and back contact of relay 212, inner lower armature and front contact 210 to ground. Relay 211 in operating closes the circuit from ground for the left hand windings of repeating coil 214 to the sleeve terminal of the group 202 to hold the selector S in actuated position.

The operation of relay 211 also closesan obvious circuit for the operation of relay 216. This relay in operating closes a circuit for the transmission of ringing tone to the calling subscriber as follows: `tone source 217, outer right hand armature and back contact of relay 218, condenser 219, outer left Ahand armature and front contact of relay 216,

the ring conductor of the trunk through the subscribers line loop, to the tip conductor to ground at the upper left hand winding of repeating coil 205. This tone indicates to the calling subscriber that the toll operator has been signalled.

Relay 216 in operating connects at its right hand armature an inner left hand armature and front contacts, ground and battery from the windings of relay 212, through the right hand windings of repeating coil 205, upper armature and lower outer armature and front contacts of relay 210, the tip and ring conductors of trunk F, the winding of the polarized relay 101 and the high resistance 102. This circuit" causes the operation of the polarized relay 101 which in turn closes an obvious circuit for the operation of relay 103. This .relay in operating its lower armature, closes a circuit for the lighting of lamp 104; this cir; cuit being completed through the left hand armature and back contact ofV relay `105. Lamp 104 lights to indicate to the toll oper# ator that a connection is decided over' this trunk.

The toll operator answers this call in the same manner as hereinfore describedin connection with the call over trunk T and .the low resistance bridge across the tip and ring conductors of trunk F causes relay 212l to operate. Relay 212 in operating closes a circuit for relay 220 as follows battery, winding of relay 220 outer left hand armature and front contact of relay 212 to ground at the armature and front contact of relay 211 Relay 220 closes the circuit for the operation of relay 218 as follows: battery, right hand winding of relay 218, armature and frontcon# tact of relay 220, left hand armature and back contact of relay 222, inner left hand armature and front contact ofk relay 212 to ground. Relay 218 in operating provides a locking cir# cuit for itself from battery, left hand winding and inner left hand armature and front contact of relay 218, outer left hand armature and back contact of relay 223 to ground at the arn'iature and front contact of relay211. Relay 218 by opening the connection at its outer right hand armature and back contact removes the tone for the calling subscriber supplied from the tone source 217. This relay also provides a holding circuit'for relay 211 by establishing a connection to ground' at its inner right armature and back contact. This is for the 'purpose of holding relay 211 operated and the preceding switch busy as long as the toll operators cord is connected to the trunk.

The operation of relay 218 causes connections to be made forithe automatic nreturn of the coin that the subscriber deposited toenable him to call. The first effect of the operation of this relay will be the operation" of relay 206 over a circuit as follows: battery, winding of relay 206, outer right hand armature and back contact of relay 223, outerleft handarmature and front contact of relay 218 to ground. Relay 206 in operating closes a circuit for'the starter relay 228 of the circuit R which is common to a plurality of trunks such as F. An ordinary step-by-step switch having contact banks 229,230, 231 and 232, and a stepping magnet 233 are provided-in this common circuit for the momentary application of a high voltage current to the line forthe return of the coin trough the izo operation of coin magnet 236 at the operatorlsk relay 236, middle lower armature and front contact of relay 206, to ground at the left hand armature and back contact of relay 237.

ing of relay 238, left hand armature and bac-k i contact of relay 240, brush of bank 229 to ground at the inner lower armature and back contact of a relay corresponding to relay 206 ofthe trunk to which the brush of bank 231 happens to be connected. It should be understood thatfthe brushes of this step-by-step switch remain on the terminals of the last trunk that employs this common equipment RQ The operation of relay 238 closes an obvious circuit for the stepping magnet 233 which in operating moves the brushes of the switch to the terminals of the next trunk and also opens the circuit for the relay 238 which in releasing opens the circuit for the stepping magnet. In this manner the stepping magnet is alternately operated and released to stepthe brushes of the switch as long as a ground is found on the bank 229. VVhon the brush of bank 229 connects with the terminal associated with trunk F no ground will be present on this terminaldue to the fact that the relay206 is operated, but instead a battery connectionwill be associated with vthis terminal through the winding of relay 223. The marginal relay 238 willV therefore not again be operated and consequently the stepping magnet will cease operating.

Itshould be noted that a connection is now established for the operation of relay 240 the winding of this relay is connected to ground. This relay is normally short-circuited by the ground atthe relays corresponding to relay 206 during the operation ofthe switch. e rvThe marginal relay 238 cannot operate as theresistance to ground through the winding of relay 240 is too high. Relay 240 yoperates in the circuit from the starting relay 228 through the armature and back contact of stepping magnet winding of relay 238, the winding of relay 240 to ground. As relay 240 operates direct ground will be connected at the left hand armature and front contact of this relay for the operation of relay 223. The circuit for relay 223 may be traced as follows: battery, through the winding of relay 223, make-before-break contacts of this relay, inner lower armature and front contact of relay 206, the terminal on bank 229 of this trunk, left hand armature and front contact of relay 240 to ground. Relay 223 in operating closes a locking circuit for itself through its inner right hand armature and front contact to ground at the armature and front contact of relay 211. Relay 223 in oper ating opens the locking circuit for relay 218 at its outer left hand armature and back battery, winding ofrelay 206, terminal on bank. 230 of trunk F, the brush of this bank, outer right' hand armature and front contact of relay 240 to ground. Relay 223 also closes at its inner left hand armature and front contact. a connection for repeating coil 214 to the trunk F for class of ,service tone purposes. The application of class of service tone in this trunk is the same as for trunk T and need not therefore be described. Y

Returning now to the operation ofrelay 240 the lirst effect in the common circuit R from the operation of this relay will be the closing of a circuit for relay 242, as follows: battery, winding of relay 242, make-beforebrcak contact of this relay, middle right hand armature and front contact of relay 240 through the interruptor 243 to ground when a connection is established through this interrupter. Relay 242 in operating closes alocking circuit for itself through its left hand armature and front contact and the outer right hand armature and front contact of relay 240. The operation of relay 242 now establishes a circuit for the operation of relay 244 as follows: battery, through the connecting segments of interrupter 245, left hand armature and back contact of relay 246, right hand armature and front Contact of relay 242, winding of relay 244 to ground. It should be noted that if the connecting segments of f interrupters 243 and 245 are such that' the y connection through interrupter 245-is established a sufficient period after thc connection established through interrupter 243 to permit the relay 242'to operate, the relay 244 will be operated by the interrupt-er 245- for the full period of connection. This interrupter 245 may be so constructed that the circuit is open for half a second and closed for half aI second alternately and relay 244 will now be operated for a half second period. lhen relay 244 operates the interrupter 245 will be connected through the outer left hand armature and back contact of this relay and the right hand armature and front contact of relay 242. through the winding of, rel ay 244 to ground so that the circuit for holding rel ay244 will be dependent on the closure of its own contamtsn The original energizing circuit for relay 244 just traced will be openat the left hand arma@ ture and back contact of relay 246 due to the operation of this relay on the operation of relay 244. The circuit for relay 246 is as 'fol` lows: battery, right hand winding of relay 246, middle left hand armature and front contact of relay 244 to ground. Relay 246 provides a locking circuit for itself through its inner right hand armature and front- Contact to ground at the inner right hand armature and front contact of relay 240.

The operation of relay 244 closes a connection from battery and ground through its inner right `hand and left hand armatures and front contacts, through the brushes of banks 281 and 232 vand the conductors of trunk F, through the upper outer and lower outer armatures and front contacts of relay 206- to the tip and ring conductors of the trunk F to switch S. It should be noted that this connection of battery and ground is a reversal of the normal connection through repeating coil 205 and relay 204. '.lhe pur pose of this connection is to establish certain changes through switch S in circuits of this general type, but as these changes form no part of this invention they need not be described.

When the interrupter 245 opens the above traced circuit for relay 244 this relay will release and a circuit thereby closed for the operation of relay .248 as soon as interrupter again is connected to battery. rwhis circuit may be traced as follows battery, interrupter 2457 outer lefthand armature and bach con tact of relay 244, outer right hand armature and front contact of relay 246, Winding of relay 248 to ground. Relay 248 Will be held operated as long as the connection through interrupter 245 is maintained, which may be 0ne-half of a second. The operation of this relay Will now supply current from the 110 volt supply at 250 through the left hand armatures and front contacts of this relay, inner left and right hand armatures and baclr contacts of relay 244, brushes of banks 281 and 282, tip and ring conductors of trunk F over the connection to the calling subscribers set for the operation of the coin magnet 284 to refund the coin.

The operation of relay 248 closes an obvious circuit for the operation of relay 236. A holding circuit for relay 246 through the left hand Winding thereof will be established by the operation of this relay. It should be noted that relay 286 in operating opens the original energizing circuit for relay 228 but as long as relay 248 is operated relay 228 Will be maintained operated over a circuit follows: battery, Winding of relay 228, outer right hand armature and front contact of relay 248, to the ground at the relay 237 as hereinbefore traced. When relay 248 releases at the end of the one-half second period, relay 236 Will release, lout due to its slow-torelease characteristics this release Will not take place until after the circuit for relay 228 has been opened at the outer right hand armature and front contact of relay 248. Consequently relay 228"Will release during'the open period of its circuit and cause the release of the relay 240. Relay 240 in releasing causes the release of relay 242, while relay 236 causes the release oi' relay 246. rlhis relay in releasing closes a portion of the circuit from the interrupter 245 to relay 244 but relay 242 is released at that time relay 244 cannot again operate. Consequently the interrupters 243 and 245 Will have no further etl'ect and this common circuit R is now ready for use by another trunk. The release of relay 240 also opens the holding circuit for relay 206 which releases and connects the tip and ring conductors through to the repeating coil 205.

This trunk is also, as hereinbefore inentioned, arranged to pass the classV of service tone to the toll operator in the saine manner as trunk T. The class of service tone may also be removed from the trunk by the toll operator, by the operation of key 1ll.`

A connection between the calling subscriber and the toll operator is now completed With the talking battery and ground supplied for the callingl subscriber through the Winding of relay 204 and the ground at the repeating coil 205. The calling subscriber may give the number of the Wanted subscriber to the toll operator and the toll operator may establish a connection to the subscriber in the usual manner. Conversation between the calling subscriber and the called subscriber may therefore begin as soon asthe calling subscriber has deposited the proper amount of coins required for the call.

lThe toll operator instructs the calling subscriber to vdeposit this amount and arrangements are made for refunding or collecting the depositedr coins in this circuit .in the saine manner described in connection With circuit T. Supervision of the circuit may be had in the saine manner as described in connection with trunk T and the release of the connection after conversation ceases n'iay also be made in the same manner as described in connection with trunk T.

lt should be understood that While this invention has been described in cnnnec'tion with a trunking system in Which the trunk may be seized through the medium of automatic switches and it has been assumed that the subscriber will not be able to dial until a coin has been deposited, the invention is not limited to systems of this kind, but may be equally Well applied to other systems, for example, Where the coin is deposited after the trunk has been seized, Without departing from the spirit of the invention.

What is claimed is:

l. In a telephone system, a subscribers T ing said subscribers line and device to said tion with said trunk at the opposite end thereof, means responsive to the actuation of said first means and the association of the cord with the trunk for actuating said device to refund a coin deposited therein.

2. `In a telephone system, a subscribers line, a coin collect and refund device associated therewith, a trunk, means for connecting said line and device to said trunk, at one end thereof, an operators cord for association with .said trunk at the opposite end thereof, a source of current, means responsive to the actuation of said first means and the association of the cord with the trunk for applying current from said source over said line to said device to actuate it to refund a coin deposited therein.

3. In a telephone system, a subscribers line, a coin collect and refund device associated therewith, a trunk, means for connect-- trunk at one end thereof, an operators cord for association with the other' end of said trunk, a source of current, and means responsive to the connection of said line and cord to said trunk for applying' current from said source to said device for a definite period of time to actuate said device to refund a coin deposited therein.

4. In ateiephone system, a subscribers line, a coin collect and refund device associated therewith, a trunk, means for connecting said subscribers line and device to said trunk at one end thereof, an operators cord for association with the other end of said trunk, a source of current, an interrupter, and means responsive to the actuation of said means and the association of the cord with the trunk for applying current from said source to said device under control of said interruptor to actuate said device to refund a coin deposited therein.

5. In a telephone system, a subscribers line, a coin collect and refund device associated therewith, a trunk, means for connecting said line and device to said trunk at one end thereof, an operators cord for association with said trunk at the opposite end thereof, a direct current source, a circuit interrupter, a circuit and relay arrangement controllable by said interrupter, means responsive to the actuation of said first means and the association of the cord with the trunk for placing the circuit and relay arrangement under control of said interrupter toiapply current from said source over said line to said device for operating it for a period equal tovone circuit closure of said interrupter to refund a coin deposited in said device.

6. In a telephone system, a subscribers line, a coin collect and refund device associated therewith, a plurality of trunks, means for connecting said line and device to any one of said trunks at one end thereof, an operators cord for association with any one of said trunks at the opposite end thereof, and means common to all of said trunks responsive to the connection of a trunk to said` line and said cord for actuating said device to refund a coin deposited therein.

7. In a telephone system, a subscribers line, a coin collect and refund device associated therewith, a plurality of trunks, means for connecting said line and device to any one of said trunks at one end thereof, an operators cord for association with any one of said trunks at the opposite end thereof, a source of current, a switching means, and means for actuating said switching means responsive to the connection of a trunk to said line and said cord for applying current from said source over said trunk and line to said device to actuate it to refund a coin deposited therein.

8. In a telephone system, a subscribers line, a coin collect and refund device associated therewith, a trunk, means for connecting said iine and device to said trunk, an operators cord for association with said trunk, and means responsive to the actuation of said first means and the association of the cord with the trunk for actuating said device to refund a coin deposited therein.

9. In a telephone system, a telephone line, a coin collect and refund device associated with said line, a trunk, means for connecting said line to said trunk, an operators cord for making connection with said trunk, a source of current, and means responsive to the actuation of said first means and to the connection of the cord with said trunk for applying current from said source over said line to actuate said device to refund a coin deposited therein.

In witness whereof, I hereunto subscribe my name this 24th day of October A. D.,

RALPH L. QUASS.

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