US2091541A - Telephone system - Google Patents

Description

A118- 31, 1937. si B. wrLLlAMs TELEPHQHE SYSTEM Filei April 18. 1935 :s sheets-sheet 1 ATTORNEY ng- 31, 1937. s. B. WILLIAMS 2,091,541

' TELEPHONE SYSTEM Filed April 18, 1935 :5 `swans-sheen; 2

/Nl/E/vro/P 5. B. W/LL/AMS A TTORNEV Aug. 31, 1937. s. B. WILLIAMS 2,091,541'

TELEPHONE SYSTEM Filed Apr'ii 1e, 1935 s sheets-*sugers FIG. 5-

, /N VE /V TOR s. W/L L MM5 A TTORNEV Patented Aug. 31, 1937 UNETE Bell Telephone Laboratories,

Incorporated,

New York, N. Y., a corporation of New York Application April 18, 1935, Serial No. 16,947 13 Claims. (Cl. Ilill-6.31)

This invention relates to telephone systems and particularly to those having coin-controlled stations.

The objects of the invention are to extend the range of service available to patrons of coin sta.-

tions; to enable them to call different classes of lines without assistance of an operator; to enable them to refund coins deposited for the purpose of making free calls; and to otherwise improve systems of this character.

It has been the practice heretofore to equip coin-controlled stations with dials to enable the patron to complete certain calls without the y assistance of an operator. In some of these prior 10 systems, if he wishes to make a long distance call or a call to a free line, he must deposit a coin to obtain the service of the operator, and

in other systems he may, without depositing a coin, obtain her assistance by dialing a particular number.

A feature of the present invention is to improve these prior arrangements by means of a system in which the coin station is equipped with a device so that the patron may refund his e5 deposited coin at any time, and which system is so arranged that he mai7 refund his coin without releasing the connection if he has called a free line, but, if he attempts to recover the coin on a call to a line for which a coin should be collected, the connection is automatically released. To this end the free lines are segregated in special final switches which are provided with timing devices to delay the release for an interval sucient to allow the refund of the coin at the calling station and the reclosure of theline to hold the connection.

A further feature is a refund key at the coin station so constructed that it not only refunds the coin when actuated but opens the line and then recloses it after a measured interval of time.

These and other features of the invention will be described more fully in detail in the following specification which should be taken in connection with the` accompanying drawings.

Referring to the drawings:

Fig. l shows in a diagrammatic form a coin station A and a line l, a lineefinder LF having access to the line l, a first selector switch SI,

and a second selector switch S2.

Fig. 2 shows in diagrammatic form an alternative coin station B and a line l50 to which the line-lnder LF may have access.

Fig. 3 shows a connecter switch CI wired in accordance with this invention and, having access to any called subscriber station such as X, a connecter switch C2 of a type well known to the art and having access to any called substation such as Y, and a circuit to an intercepting operators position 0 also wired in a manner well kno-wn to the art and which gives an indication to an intercepting operator who may complete 'the call.

Figs. 4 and 5 show details of the coin return mechanism of Figs. 1 and 2 in the different operated positions. The numerical designations correspond with those shown in Fig. 1.

Fig. 6 shows in diagrammatic form the special dial used in Fig. l. The numerical designations of the springs correspond to those of the dial shown in Fig. 1.

It is to be understood that the invention is not limited to the use of the particular apparatus shown in the drawings, as the apparatus and the circuits may be changed or modified in order to perform the desired circuit functions. Only such parts of the circuits as are necessary to illustrate the invention have been shown.

Substation A, in addition to the usual receiver and transmitter, comprises a special coin collect mechanism consisting of contact springs 3S, a coin chute 3l, a coin trigger 32, a coin trigger lever 29, a coin trap 33, a non-polarized coin magnet M, and a copper oxide rectifier i5. Substation A has also a special governor and coin return mechanism Gl whereby the calling subscriber may return his coin when making a free call. This coin return mechanism Gl consists of a coin return button Gli attached to coin return lever 38. One end of coin return lever 38 to which is attached return button lill protrudes from the frame 56 of the coin box and the other end rests on roller i3 and has lever arm El suitably attached. Associated with lever arm 4l! is a T-arm 35 pivoted at 3&3. The `i`arm 35 has a spring 3l suitably attached at one end t l. The other end of the spring 3l is attached to a pin SB on the frame of the coin box. In the normal position T-arm 35 rests against the stop 62, and the control springs lil are closed as shown in Fig. l. Associated with the coin return lever 38 is a gear wheel d5 which is attached to the end 46 of a shaft 4l. Adjacent to the gear Wheel l5 is a spiral spring 5i) one end of which is attached to the frame of the coin bio-X and the other end of which is attached to a link 138 which in turn, is suitably attached to shaft lil. At the other end of shaft 4l is attached a lever arm 54 associated with a ratchet 5i. Ratchet 5l is actuated by a helical spring 53. Associated with ratchet 5| is a ratchet wheel 52 which in turn is connected to governor 56 by means of shaft 55.

In addition to this apparatus, substation A has a special dial in order to prevent the calling sub- 5 station A from dialing any digit other than 0 without depositing a coin in the coin mechanism. This dial is shown diagrammatically in Fig. 6, and its outward appearance is similar to that of any standard dial. It has a finger wheel E34, l a number plate H85 and a nger stop lSB. The interior of the dial has a special construction and consists of contact springs 2 to 9 inclusive, a cam ES@ which rotates in unison with the finger wheel E813, a lever arm ISI which has 4a roller i8@ l5 conveniently attached at one end and which joins spring li so that any movement of lever arm i9! is transmitted to spring 4, a collar l8l having .an inner surface E82 and an outer surface it, a pulse pawl I8?, a pulse pawl spring E92 and a pulse wheel H39. When the iinger wheel it is moved from its normal position the cam i9@ moves in a clockwise direction and permits springs 5 and 'i to make contact and springs 65 and 5 to break contact. As soon as the iinger wheel i 84 is moved in a clockwise direction, roller I8@ on lever arm i9! will contact with the surface l82 of collar lili and move lever arm i9! in such a manner as to keep springs 2 and l from breaking contact and springs 2 and 3 from making contact until the digit 0 has been completely dialed, when the roller I8@ will drop from surface 32 of collar ll and permit spring 2 to make contact with spring 3 and spring 4 to break contact with spring 2. When the finger wheelV it@ is released the roller H80 on lever arm i9! will contact with surface |83 of collar l 8i in such a inanner as to hold springs 2 and i open and springs 2 and S closed until the finger wheel l has restored to its normal position where the lever arm lill again assumes its normal position as shown in Fig. 6. The pulsing springs 8 and 9 are operated in the usual manner by pulse pawl itl which is pivoted at 88 and actuated under control of the pulse wheel l89 and the pulse pawl spring 92.

The finder LF, the selectors Si and S2, and the connecters CI and C2 are in general of the well-known type, such as the Strowger switch, except for circuit modications made in connecter Cl in accordance with this invention. Other types of switches may be used if desirable.

Referring to Fig. l, let us assume that a party at the calling substation A removes the receiver 23 from the switchhook i9 to make a call to the subscriber of line X. In this case payment is not required, although a coin must be deposited temporarily to enable him to make the call. When the receiver 23 is removed from the switchhook i9 a metallic loop circuit will be closed through substation A from terminal llt, over line l, conductor lil, the back contacts of con tact springs 35B, springs 3 and A of the dial,rconductor 25, transmitter i6, conductor i8, the left contacts of switchhook i9, the left winding of induction coil 29, conductor 2l, line l to terminal ll. A receiving circuit will be closed from conductor iii, through condenser 22, the right winding of induction coil 2i), the right contacts of switchhook l, receiver 23, conductor 2li, contact springs 5 and B of the dial to conductor it.

The brushes i3 and 'M of the line finder LF' will connect with the terminals Till 4and lil, in a manner well known to the art, and extend the metallic loop circuit of substation A described above through to a selector Switch Si. The selector switch SI will function to send dial tone to the calling substation A and to place negative battery on conductor 2| and ground on conductor l il of the metallic loop circuit of substation A.

Under these circumstances dial tone will be heard in the receiver 23 of substation A. If no coin has been deposited at the calling substation A, the contact springs 30 of the coin mechanism of substation A will not operate and since contact springs 2 and 3 of the dial Will not make contact when any digit other than 0 is dialed the pulsing circuit will no-t be closed through. This prevents dialing from the calling substation A until va coin is deposited in coin chute 3l of the coin mechanism.

If on or before receiving the dial tone, the calling party deposits a coin 28 in the coin chute 3i, the coin 28 will pass through the o-oin chute 3l to the coin trap 33 thereby operating the coin trigger 32 which in turn will allow the coin trigger lever 29 to operate. Operation of the coin trigger lever 29 will cause the contact Springs Eil to function closing the front contacts and opening the back contacts of said Contact springs Opening of the back contacts will open the transmitter circuit. Closure of the front contacts of springs 3i! will close a loop circuit through conductor il, the pulsing springs t and 9 of the dial, conductor lli, thence in parallel, one path leading to copper oxide rectifier l5, winding of coin magnet lll, conductor l2 to conductor i8, and the other path leading from conductor i3, rectier il, transmitter it to conductor i8. The copper oxide rectiers i5 and ll are unipolarity devices which will not permit current toy pass through in the direction opposite to that indicated by the symbolic arrowhead. Therefore, coin magnet lli will not operate. However, current does flow over the loop and through the path including rectier il'. This holds the switches while the dial is in its normal position. When the dial is moved from normal to send a digit, it completes the pulsing circuit through from conductor l@ to conductor il, pulsing springs 8 and 9 of the dial, 01T normal springs t and l of the dial, conductor it, the left contacts of switchhook i9, the left winding of induction coil 2l) to conductor 2l. Contact springs 2, 3 and l of the dial will not operate when a digit other than 0 is dialed. As the dial is moved off-normal,

contact springs 5 and t of the dial break contact to open the receiver circuit and contact springs t and l make contact to place a short circuit around the coin magnet l@ `and at the same time to close the pulsing circuit to conductor i3. dial is then operated and released in the usual manner causing the selector Sl and the selector S2 to function in a manner well known to the art.

Assume that selector S2 seizes connecter CI thereby closing the subscriber loop of substation A from brush i3 of line iinder LF to conductor it of. connecter Cl, the upper back contact of relay 395, conductor 396, the upper winding of relay Stil to ground, positive grounded battery, the lower winding of relay 35i, conductor Sill, the lower outer back contact of relay 335, conductor lll to brush lll of line finder LF. Closure of this loop circuit causes relay Sti to become energized and close its front contact, thereby closing a circuit from ground through the front contact of relay 3M, winding of slow-to-release relay 3632 to battery. Relay 3632 becomes energized and closes a circuit from ground through the left outer front Contact of relay 362, winding of slow-to-release relay 303 to battery. Relay 3% The.

becomes energized and closes a circuit from ground through the left front contact of relay 303, winding of slow-to-release relay 304 to battery. Relay 304 becomes energized and closes a circuit from ground through the left outer front contact of relay 304 to the sleeve conductor 18 of connecter Cl for holding the preceding switches in their operated positions and to guard the connecter Cl from seizure by other hunting selector circuits.

As the pulsing contacts 8 and 0 of the dial in subscriber station A are opened, relay 30| will release and close a circuit from ground through its lower back contact, the left inner front contact of relay 302, the back contact of the vertical off-normal springs V. O. N., winding of relay 3|0, winding of vertical magnet 3|2 to battery. This causes relay 3|0 and Vertical magnet 3|2 to become energized. Operation of the vertical magnet will cause the switch to take on step in a vertical direction. As soon as the shaft of connecter CI is moved from the normal position on the rst vertical step, the V. O. N. springs will operate and transfer the operating and holding circuit for relay 3|0 under the control of the left front contacts of relay 3|0 and the lower front contacts of the V. O. N. springs. When the pulsing contacts 3 and 9 of the dial close, relay 30| will reoperate. Relay 302 being slow to release will remain operated during the pulsing of a digit and thereby holds relays 303 and 304 in their operated position. Relay 3|0 being slow to release will remain operated also during the pulsing of a digit. As the pulses are sent out from the dial over the subscriber loop, relay 30| will operate and release for each pulse of the dial and connecter CI will take a vertical step for each of the pulses received. As soon as the first set of. pulses have been transmitted, relay 30| will remain in the operated position and relay 3|0 will release.

The next set of impulses received from the dial will again cause relay 30| to release and to reoperate as previously described. Relay 30| in releasing will close a circuit from ground through its lower back contact, the left inner front contact of relay 302, the lower front contact of the V. O, N. springs, the left back contact of relay 3|0, the right outer back contact of relay 309, conductor 3|5, the lower inner back contact of relay 301, winding of rotary magnet 3H to battery. A circuit will be closed also from ground on conductor 3|5, conductor 3|0, winding of relay 303 to battery. Th-e rotary magnet 3I| will function and cause the shaft of. the connecter Ci to step in a horizontal direction in response to the number of pulses received from the subscribers dial. Relay 302 will again remain operated as during the vertical stepping described previously. During the functioning of rotary magnet 3H, relay 300 will operate in multiple with rotary magnet 3H and, being slow to release, will remain operated during the series of pulses to close the circuit for testing the called line.

If the called lineV is busy, ground will be connected to the sleeve terminal 342. This will cause relay 309 to operate over a circuit extending from terminal 342, brush 332, conductor 3|1, the right front contact of relay 308, the lower back contact of relay 301, winding of relay 309 to positivegrounded battery before relay 308 releases. Relay 300 having operated will lock as the relay 308 releases over a circuit extending from positive grounded battery, winding of relay 309,

v 309, left outer front contact of relay 304 to ground. Opening of the right outer back contact of relay 300 will open the holding circuit for relay 300 and for the rotary magnet 3| Closure of the left front contact of relay 309 will close a circuit to busy tone over conductor 3|1. This busy tone will be extended to the calling subscriber in a manner Well known to the art.

If the called line is idle, battery will be connected to the sleeve terminal 342. Relay 309 will not operate therefore, and the connecter C| will cut through to the called line upon the release of` relay 308. When the called line is seized, relay 301 will operate over a circuit through its lower winding upon the release of relay 308. The operating circuit for relay 301 will extend from battery on terminal 342, through brush 332, conductor 3|1, the right outer back contact of relay 308, lower winding of relay 301, the right inner back contact or relay 300 to ground through the left outer front contact of relay 304. The circuit for operation of relay 301 is thereby controlled from .ground at relay 304 and acts as a guarding potential on the sleeve terminal 342 until relay 301 has operated and connected ground through its lower front contacts to the sleeve terminal 342. The circuit through the lower winding of relay 301 serves only to operate the upper inner front contacts of relay 301. This will close a circuit from positive grounded battery through the winding of rotary magnet 3||, the upper winding of relay 301, the upper inner front contacts of relay 301 to ground on the left inner front contacts of relay 304. This circuit is maintained until the release of the connecter CI. The operation of relay 301 also closes a ringing circuit from the ringing machine 3|8, through resistance 319 and condenser 320 in parallel with L.

the lower winding of relay 300 to the loop circuit of the called subscriber X.

The called subscriber at station X is signaled in any desired manner by use of the ringing signals. As the ringing continues a ringing tone is sent to the calling station A in a manner well lrnown to the art.

The calling subscriber at station A has instructions when calling a free line, such as line X, to depress the pushbutton 64 to obtain refund of coin 28 when he hears ringing tone. When the pushbutton 04 is depressed, coin return lever 30 engages the coin trigger lever 29 and the coin trap 33. With the coin return lever 38 in the operated position the coin return mechanism used in Fig. 1 assumes the position as shown in Fig. Ll. The end of coin return lever 38 causes the coin trap 33 to pivot about its fulcrum 05 thereby causing the coin Z8 to be dropped in the direction indicated` by the arrow 21 and thus returned to the calling subscriber at station A. As the coin return lever 38 is moved from the normal to the operated position, the teeth 44 on coin return lever 38 engage gear 45 thereby causing gear 45 to turn in a clockwise direction. Turning of gear 45 will cause shaft 41 to turn and thus cause the lever arm 48 to wind up the spring 50 and cause the ratchet 5| to turn in a clockwise direction inside of the ratchet wheel 52. Also, as the coin return lever 38 is moved from the normal to the operated position, arm 00 attached to coin return lever 38 moves away from surface 33 of T-arrn 35 and makes contact with surface 34 of T-arm 35 and thus causes T- arm 35 to pivot about fulcrum 30. This permits 'illustration of Fig. 5.

stud 63 on T-arm 35 to move away from contact springs 4| thereby permitting contact springs 1H to break contact and open the subscriber loop circuit.

As the pushbutton 64 is released, the ratchet engages the teeth of ratchet wheel 52 thereby affording a rigid connection between governor 5G and the coin return lever 38 by means of the shaft 41. When pushbutton 64 is released the spiral spring 50 tends to cause shaft l1 and the entire timing mechanism GI to turn in a counterclockwise direction. The governor 55 is so timed that the control springs 4| will be held open sufliciently long to permit the release of all selectors and connecters other than free call connecters, such as Ci of Fig. 3. In the case of connecters such as Ci slow-to-release relays 302, 303 and 334 have been placed in cascade to slow up the release of the connecter until the contact springs 4i become closed after the return of the coin 28 by the subscriber at calling station A. As soon as the timing mechanism GI restores, arm 35 recloses contacts 4|, and line relay Sill in connecter C| reoperates to reestablish the holding circuits of slow relays 352, 333 and 3563. And since this occurs before relay 33t has time to release, the connection is held. This makes it possible for the calling party to recover his coin when he calls a free-line.

When the receiver is removed at the called station X, a circuit is closed to operate relay 305 and cause the ringing signal to cease in a manner well known to the art. Relay 305 will operate to close its upper inner front contacts due to the current flowing through its lower winding. This circuit leads from battery, the upper winding of relay 335, the upper inner front contacts of relay 3BG, to ground through the left inner front contacts of relay 354. The operation of relay 303 will connect the talking leads through to the windings of relay 3135 which now supplies talking battery to the called station X. The called station X and the calling station A are now connected for talking purposes. Under this condition relay 335 will operate. Operation of relay 305 will reverse the direction of the current flow in the metallic loop circuit of substation A described before which is in series with the windings of relay 35i. This reversal is accomplished by transferring the negative battery supply from the lower back Contact to the lower front contact of relay 365 and by transferring the ground supply from the upper back contact to the upper front contact of relay 355. The direction of the current flow is reversed therefore through conductor i3, copper oxide rectifier I5, coin magnet ifi and conductor l2. The copper oxide rectifier i5 will permit current to pass through this circuit under this condition and the coin magnet i4 will operate. Operation of the coin magnet Ut will operate the coin trap 33 as shown in the detail Operation of the coin trap 33 will reset the coin trigger lever 29, the coin trigger 32 and the contact springs 35. With the functioning of the contact springs 30, the front contacts will open and the back contacts will close. Opening of the front contacts will open the circuit through the copper oxide rectifier l5 and the coin magnet i4 thus removing the bridge from the line and permitting coin magnet M to release. Closure of the back contacts of contact 3U will close the talking circuit through to the transmitter l5. The calling party may then talk to the called subscriber in the usual manner.

If it is desired to abandon the call at the substation A because the line of the called subscriber X is busy or because the called subscriber X does not answer, the receiver at substation A is replaced on the switchhook I9 and the subscriber at station A depresses pushbutton 64. When the push button 64 is depressed the coin return mechanism GI functions and the coin 28 is returned to the subscriber as described heretofore.

After conversation is completed and the subscriber at called station X disconnects, relay 335 will release and when the calling station A disconnects relays 30|, 332, 333 and 334 will release which in turn allow relay 331 to release. With the connecter Cl in this condition a circuit is closed from positive grounded battery, winding of release magnet 3|3, upper front contacts of the V. O. N. springs, upper back contact of relay 391, right back contact of relay 304, left back contact of relay 332 to ground on the lower back contact of relay 30| The release magnet 3|3 being energized will release connecter Cl which will restore the connecter shaft to normal. When the shaft returns to normal the V. O. N. springs are operated thereby opening the circuit to the release magnet 3|3 and allowing it to release. When the called station X or the calling station A are disconnected, supervisory signals are given over conductors 3|5 and 3|6 to common alarm equipment not shown. The removal of ground from conductor 78 also causes the release of finder LF and selectors Sl and S2.

Assuming that the subscriber at station A desires to make a call to line Y for which payment is required, he removes the receiver 23 from the switchhook i9. The line finder LF and selectors Si and S2 will function` as described heretofore when the subscriber at station A makes a free call, except that, because of grouping arrangements, the selector S2 will seize a connecter such as C2 by way of conductors i9, 83 and 8|. When the connecter C2 is seized the subscriber loop is closed to battery and ground through the windings of relay 328. Relay 328 will operate and close a circuit from ground through its lower front contact, winding of slow-to-release relay 32i to battery, thereby causing relay 32| to operate. As the digits are dialed at substation A, relay 323 will release on the rst pulse of the dial but relay 32| will remain operated. A circuit will be closed thereby for operating the connecter C2 in the same manner as outlined heretofore for connecter CI, relay 32| remaining operated during the pulsing for any digit.

The called subscriber Y is signaled in a manner well known to the art. If the subscriber' at calling station A depresses push button 53 at any time before the called station Y answers, the subscriber loop will be held open long enough by the governor assembly GI for the relays 323 and 32| to release, thereby closing the circuit to the release magnet 322 and allowing the connecter C2 to restore to normal. When the called station Y answers a reversal of battery and ground over the calling subscriber loop at station A is created in connecter C2 in a manner well known to the art. The coin collect mechanism at station A will function as outlined heretofore when a battery reversal was made when using connecter Cl and the deposited coin will enter the Vcoin hopper in the direction indicated by arrow 2t?.

Assuming that a call originating at station A has been routed by selector S2 to an intercepting operators position 0 by way of conductors 82, 83 and 84, the transmitter circuit at station A will extend from conductor I, front contacts of springs 3G, conductor I l, pulsing contacts 8 and 9 of the dial, copper oxide rectier Il, conductor 25, transmitter l5 to conductor I8 and the re- 5 ceiving circuit Will extend from conductor IFJ through condenser 22, right Winding of induction coil 2Q, right contacts of svvitchhook I9, receiver 23, conductor Eil, contacts 5 and 6 of the dial to conductor i8. This circuit arrangement allows the calling subscriber at station A to converse with the intercepting operator at position O Without disposing of the coin. It no charge is to be made the coin may be refunded at the calling station A in the manner outlined heretofore. If a charge is to be made the operator at position 0 completes the call in a manner Well known to the art. When the called station answers a battery reversal is obtained which causes coin mag-v net I4 to function and collect the coin 23 in the Same manner as outlined heretofore.

Let us assume that the calling substation A desires to obtain a connection to the zero operator. In this event no coin is required. The receiver 23 at substation A is removed from the 25 switchhook I9, and the dial at substation A is operated and released in accordance with the code number of the Zero operator, which is usually 0. As the dial is moved from the normal position, springs 5 and l of the dial are closed and springs 5 and E are opened. Spring 2 of the dial will not make contact with spring 3 and spring 4i Will not break contact from spring 2 until the dial has been fully operated to the 0 position when said springs will operate and remain locked in their operated positions thus closing the pulsing circuit and opening the transmitter circuit to prevent pulsing through the transmitter Iii until the dial has restored to normal. Opening of contact springs 2 and i will open the circuit through the transmitter i6. Closure of contact springs 2 and 3 will complete a metallic pulsing circuit through conductor 2l, the left winding of the induction coil ES, the left contacts of svvitchhook i8, conductor i3, contacts E and 'i and pulsing contacts 8 and Q and contacts 2 and S of the dial, the back contact of contact springs 3d, to conductor I0. The selector SI will accordingly be set in accordance with its primary movement upon the proper trunk level which We will assume to be the 10th or 0 trunk level of the switch. The selector SI will function in the usual manner and extend the connection to the zero operator displaying a signal at her position as an indication that a call is in Waiting. When the call is ansvvered by the zero operator there is no current reversal in the calling line loop, thus preventing the operation of the coin magnet Ml. The zero operator will complete the call in a manner Well known to the art.

G0 Referring to Fig. 2, substation B, in addition to the usual receiver and transmitter, comprises a special coin collect mechanism consisting of contact springs l3ll, a coin chute IM, a coin trigger I32, a coin trigger lever i253, a coin trap ISE, a non-polarized coin magnet IM, a copper oxide rectier M5. substation B has also a special governor and coin return mechanism G2 the same as that described in Fig. l. In addition to this apparatus substation B is equipped With a special dial in order to prevent the calling substation B from dialing any digit other than 0 Without depositing a coin in the coin mechanism. This dial is similar to the dial shown diagrammatically in Fig. 6 and used at station A. The outward ap- 75 pearance of the dial is similar Ato that of any standard dial. It has a finger Wheel, a number plate and a finger stop identical with the parts shown in Fig. 6. The interior of the dial has a special construction and consists of contact springs 32 to lQ, inclusive. The cam Which rotates in unison with the finger wheel, the lever arm which has a roller conveniently attached at one end, the collar having an inner surface and an outer surface, the pulse pawl, the pulse pawl spring and the pulse Wheel are the same and function the same as those described in Fig. 6. The lever arm, which has the roller attached at one end, joins spring m3 so that any movement of the lever arm is transmitted to spring HB3.

When the linger wheel is moved from its normal position the cam moves in a clockwise direction and permits springs H05 and lllii to make contact and springs and lill to break contact. As

soon as the finger Wheel is moved in a clockwise direction, the roller and the lever arm will function as described for Fig. 6, in such a manner as to keep springs M32 and Ide from breaking contact and springs IilS and lli from making Contact until the digit 0 has been completely dialed When the roller and the lever arm Will drop from the surface of the collar and permit spring los to make contact With spring IM and spring W3 to break contact with spring m2. When the iinger Wheel is released the roller on the lever arm Will contact With the outer surface of the c-ollar in such a manner as to hold springs lo? and Ill?, open and springs H33 and iii@ closed until the finger Wheel has restored to its normal position Where the lever arm again assumes its normal position as shown in Fig. 6. The pulsing springs w8 and it@ are operated in the usual manner by pulse paWl.

Referring to Fig. 2, let us assume that a party at the calling substation B removes the receiver E23 from the switchhook IE@ to make a free call. Although payment is not required, he must deposit a coin temporarily to enable him to make the call. When the receiver I23 is removed from the switchhook I i9 a metallic loop circuit will be closed through substation B from terminal E98, over line E59, conductor Il, the back contacts of contact springs i3d, springs H32 and liii of the dial, conductor l25, transmitter lili, conductor H8, the left contacts of SWitchhook H9, the left Winding of induction coil H29, conductor l2l, line l to terminal ISI, A receiving circuit will be 'closed from conductor IIS, through condenser i522, the right Winding of induction coil me, the right contacts of switchhook I i9, receiver l23, conductor IM, contact springs H35 and ld of the dial to conductor H8.

The brushes of the line finder LF will connect with the terminals I9@ and EQI and extend the metallic loop circuit of substation B described above through to a selector Si. The selector Si will function to send dial tone to the calling substation B and to place negative battery on conductor l2l and ground on conductor lio of the metallic loop circuit of substation B. Under these circumstances dial tone Will be heard in the receiver IZB of substation B. If no coin has been deposited at the calling substation B, the contact springs I3@ of the coin mechanism of substation B will not operate and since contact springs IS and Iiii of the dial will not make contact when any digit other than 0 is dialed the pulsing cir-cuit will not be closed through. This prevents dialing from the calling substation B until a coin is deposited in coin chute i3! of the coin mechanism. If on or before receiving the dial tone, the calling party deposits a coin |20 in the coin chute |3|, the coin |28 Will pass through the coin chute |3| to the coin trap |33 thereby operating the coin trigger |32 which in turn will allow the coin trigger lever |20 to operate. Operation of the coin trigger lever |29 will cause the contact springs |30 to function closing the front contacts and opening the back contacts of said contact springs |30. Opening of the back contact will open the transmitter circuit. Closure of the front contacts of springs |30 will close a loop circuit through conductor the pulsing springs |03 and |09 of the dial, conductor H3, winding of coin magnet H43, copper oxide rectifier H5, conductor ||2 to conductor I 8. The copper oxide rectifier H is a unipolarity device which will not permit current to pass through in the direction opposite to that indicated by the symbolic arrowhead. Therefore, coin magnet ||4i will not operate. A parallel path leads through the retier III, which serves the same function as did rectifier il in Fig. l. Closure of the front contacts will complete the pulsing circuit from conduetor IIil, the front contacts of contact springs |30, conductor pulsing springs |03 and |09 of the dial, off normal springs |05 and |071 of the dial, conductor IIIS, the left contacts of switchhook 9, the left winding of induction coil I 20 to conductor |2I. Contact springs |02, |03 and |04?, of the dial will not operate when a digit other than 0 is dialed. As the dialis moved off normal, contact springs |05 and I 03 of the dial break contact to open the receiver circuit and contact springs i053 and |01? make contact to place a 'r short circuit around the coin magnet IM and at the same time to close the pulsing circuit. The dial is then operated and released in the usual manner causing the selector SI and the selector S2 to function.

Assume that selector S2 seizes a connecter such as C| and closes the subscriber loop thereto, the call will be completed in the manner outlined herein for substation A. When ringing tone is heard the subscriber at station B will obtain a refund of the deposited coin |28 by operation of coin return mechanism G2. rIhe talking circuit will be established as outlined heretofore for station A.

Assuming next that the called station B desires to make a call for which payment is required, the circuit at station B, the line finder LF, the selectors SI and S2 and the connecter C2 will function as outlined herein for station A when making a similar call. When the called station Y answers, the current ow through the subscriber loop at station B will be reversed in the manner described heretofore in the operation of station A, thereby reversing the current flow through conductor ||3, coin magnet IM, copper oxide rectifier H5, and conductor ||2. The copper oxide rectifier I5 will permit current to pass through this circuit under this condition and the coin magnet ||4 will operate. Operation of the coin magnet II 4 will operate the coin trap I 33. Operation of the coin trap |33 will reset the coin trigger lever |29, the coin trigger |32 and the contact springs |30 and will collect the coin |28 in the manner outlined for station A. With the functioning of the contact springs |30, the front contacts Will open and the back contacts will close. Opening of the front contacts will open the circuit through the copper oxide rectifier ||5 and the coin magnet ||4 thus removing the bridge from the line and permitting coin magnet ||4 to release. Closure of the back contacts of contact |30 will close 'the talkingl circuit through to the transmitter I6. The calling party may then talk to the called subscriber in the usual manner.

If it is desired to abandon the call at the substation B because the line of the called subscriber Y is busy or because the called subscriber Y does not answer, the receiver at substation B is replaced on the switchhook IIS and the subscriber at station B depresses pushbutton of the coin return mechanism G2 to obtain refund of the coin.

On a call to the intercepting operators position 0, the circuit at station B will function in the manner outlined heretofore when making a f free call but the calling subscriber at station B must refund his coin before he can talk to the intercepting operator at operators position 0.

Let us assume that the calling substation B desires to obtain a connection to the zero operator. In this event the receiver |23 at substation B is removed from the switchhook H0 and the dial at substation B is operated and released in accordance With the code number of the Zero operator, which is usually 0. As the dial is moved from the normal position, springs |00 and I 0l of the dial are closed and springs |05 and |06 are opened. Spring |03 of the dial will not make contact with spring |04 thus keeping the pulsing circuit open and spring |03 will not break contact from spring |02 thus keeping the transmitter circuit closed until the dial has been fully operated to the 0 position when said springs will operate and remain locked in their operated positions thus closing the pulsing oircuit and opening the transmitter circuit to prevent pulsing through the transmitter Il@ until the dial has restored to normal. Opening of contact springs |02 and |03 will open the circuit through the transmitter H6. Closure of contact springs |03 and |04 will complete a metallic pulsing circuit through conductor |25, the left winding of the induction coil |20, the left contact of switchhook I I4, conductor I I0, olf-normal contact springs |00 and IOTI, pulsing contact springs |08 and |09 of the dial, conductor IH, contact springs |03 and |04, back contacts of springs |30, conductor IIB.

The selector SI will accordingly be set upon the proper trunk level which we will assume to be the 10th or 0 trunk level of the switch. The selector SI will function in the usual manner and extend the connection to the zero operator displaying a signal at her position as an indication that a call is in waiting. When the call is answered by the zero operator there is no current reversal in the calling line loop, thus preventing the operation of the coin magnet IM. The zero operator will complete the call in a manner well known to the art.

What is claimed is:

1. In a telephone system, a calling line having a coin-controlled station thereon, a rst called line and means for establishing a connection thereto from said calling line, a second called line and means for establishing a connection thereto from said calling line, refunding means for refunding a coin deposited at said station without releasing a connection established to said rst called line, and means for releasing a connection established to said second called line in response to the operation of said refunding means.

2. In a telephone system, a coin-controlled station, means for setting up a connection from said station to either of two different destinations, a refund device operable to refund a coin deposited at said station without releasing one of said connections, and means responsive to the operation of said device for releasing the other of said connections.

3.`In a telephone system, a coin-controlled station, means for establishing a connection from said station to either of two destinations, a refund device operable to refund a coin deposited at said station without releasing one of said connections, means responsive to the operation of said device for releasing the other of said connections, and means controlled from said station for releasing either of said connections.

4. In a telephone system, a coin-controlled station having an impulse dial thereat, two different called stations, automatic switches responsive to said dial for establishing a connection from the coin-controlled station to either of said called stations, a refund key at the coin station for refunding a deposited coin, means for holding the connection established to one of said called stations when the refund key is operated, and means responsive to the refund key for releasing the connection established to the other of said called stations.

5. In a telephone system, a coin line having a coin-controlled station, called lines some of which may be called free and some of which require a charge, means controlled by the deposit of a coin for enabling the party at said station to establish a connection either to one of said free lines or to one of said charge lines, means to collect the coin automatically when the called party answers, means for refunding the deposited coin before the called party answers, means for holding the connection to one of said free lines when the coin is refunded, and release means for releasing the connection to one of said charge lines .in response to the refunding of the coin.

6. In a telephone system, a calling line having a coin station thereon, called lines some of which may be called free and some of which require a charge, means controlled by the deposit of a coin for enabling the calling party to establish a connection to a free line or to one of said charge lines, means to collect the coin automatically on the response of the called party, means for refunding the coin and for opening the established connection for an interval before the called party answers, means for holding the connection to a free line to prevent release during said open interval, and release means for releasing the connection to a charge line in response to the opening of said connection.

7. In a telephone system, a calling line having a coin-controlled substation thereon, switchhook contacts at said substation for opening and closing the line, a called line, automatic switches for establishing a connection between the calling and called lines, a refund device at said substation for refunding a deposited coin and for opening the circuit of the calling line, release means controlled over said calling line for eifecting the release of said automatic switches, and means associated with said release means for distinguishing between an opening of the calling line caused by said refund device and an opening caused by said switchhook contacts.

8. In a telephone system, a calling line having a coin station thereon, a called line, automatic switches, a dial at the calling station for operating said switches to establish a connection to said called line, means at the calling station for receiving a deposited coin, refund means at the calling station operable to refund the deposited coin and to open temporarily the established connection, and means for holding the established connection for conversation after the coin has been refunded.

9. In a telephone system, a calling line having a coin station thereon, a called line, automatic switches, a dial at the calling station for operating said switches to establish a connection to the called line, means at the calling station to receive a deposited coin, m'eans at the calling station for refunding a deposited coin and for opening the connection for an interval, means for holding said connection during said interval, and means controlled from the calling station for releasing said connection.

l0. In a telephone system, a calling line having a coin-controlled substation thereon, a called line, automatic switches, means controlled by the deposit of a coin at said coin station for enabling the calling party to operate said switches to establish a connection to the called line, means for collecting the deposited coin in response to the answer of the called party, means at the calling station for refunding a deposited coin before the called party answers, means for holding the established connection after the coin has been refunded, and means for releasing the established connection.

1l. In a telephone system, a calling line having a coin-controlled station thereon, a called line of one class, a called line of a second class, automatic switches, means for establishing a connection from the coin line over Said automatic switches to the first mentioned called line, means for establishing a connection from the calling line over said automatic switches to the second mentioned called line, said second established connection including a particular one of said switches, means for refunding a deposited coin at the calling station, and means in said particular switch for holding the established connection during the refunding of the deposited coin.

12. In a telephone system, a calling line having a coin-controlled station thereon, a called line, means for establishing a connection between said lines, a refund key at the calling station for restoring the deposited coin and for opening the connection, a timing device controlled by said key for reclosing a connection at the end of an interval, and means for holding said connection during said interval.

13. In a telephone system, a calling coin line, a called subscribers line, means on the calling line for receiving a deposited coin, contacts operated by the deposited coin, means for establishing a connection between said lines, a refund key for refunding the deposited coin, for restoring said coin operated contacts, and for opening the line, a timing device set by said key and serving to reclose the line after a measured interval, means associated with the established connection for holding the same against release while said line is open, and other means for opening said line to cause the release of said connection.

SAMUEL B. WILLIAMS.

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