Totalizer circuit for coin operated telephones
United States Patent Beeman et al.  
 1 1 Apr. 29, 1975 1 TOTALIZER CIRCUIT FOR (()IN 3.307.671 3/1967 Shirley 1 14/1 N OPERATED TELEPHQNES 3.668.291) 6/1972 Robertson. Jr... 179/03 R 3.703.229 ll/l972 llowring l 1 l94/l N 1 Inventors: Robert H- Bcemun. Berkeley: 3.760.101 1 1 /73 Burns 179/63 R Robert V. Burns. &#39;linley Park. both 3.806.651 4/1974 Battriek 1 .1 179/115 ol lll. 3.814.907 6/1974 Edington et al 179/03 R 173] Assignee: GTE Automatic Electric Lahommries lm-&#34;rpwamd lrimury !:.\&#39;umim&#39;rKathleen H. (lally Nor/make Ass&#39;ixlunl lixmninur-(ierald l.. Brigance P I I 0 t 26 I97 Allurm&#39;y. Agent, or firm-Robert J. Black 1 CL c 1 [-1] Appl. No.. 409,998 ABSTRACT U Q 179/6 3 R An electronic totalizer circuit which permits a coin 6; k4 r7102 telephone to he programmed for any desired initial delisxl Fie&#39;ld 1 h 4 6 posit rate, and with minor modification to he used on i I telephones that provide prepay. semipostpay and i emergency calling modes of operation. The circuit is H6] References (nod intended as a conversion unit for coin operated tele- UNITFD STATPQ PATFNTS phones lacking totalizing capabilities.  
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 TOTALIZER CIRCUIT FOR COIN OPERATED TELEPHONES BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a coin telephone circuit and more particularly to a variable initial deposit rate totalizing circuit useful in prepay, semi-postpay and emergency calling modes of operation in coin operated telephones.  
 2. Description of the Prior Art Most of the coin telephones now in operation throughout the country are descendants of a design first introduced in 1912 by the originator of public telephones, The Gray Telephone Paystation Company. During its evolution the coin telephone has seen incorporation of such features as dial operation, anti-side tone transmission circuits, one piece hand set, conversion from 5 to service, self compensating transmission networks, printed wiring transmission networks, single coil prepay coin relays and touch calling operation.  
  Among the more recent modifications of coin telephone design have been the inclusion of totalizer mechanisms which operate in response to the deposit of coins to store coin deposit information during operation. Most embodiments of this device to date have been electromechanical in nature and are typified by that disclosed in US. Pat. No. 3,435,146 issued to E. R. Andregg and K. F. Voyles. Due to the size of the electro-mechanical totalizer mechanism it is not readily adaptable for inclusion in coin telephones not particularly equipped for totalizers.  
  Accordingly is the object of the present invention to provide a coin telephone adapter circuit that incorporates electronic circuitry with the attendant advantages of reduced size and economy for a programmable totalizer, that is readily adapted for inclusion in existing coin telephones.  
 SUMMARY OF THE INVENTION The present invention is an electronic totalizer designed for addition to existing non-totalizer equipped coin telephones. The totalizer provides the following functions: The totalizer prevents the completion of all calls until the required amount of money up to a predetermined base rate has been deposited, except when the unit is modified to provide calls for the emergency calling feature. By means of strapping options any base rate may be selected as desired in 5 increments. The present totalizer controls the existing coin operated telephone circuitry and may be used with coin telephones equipped with conventional rotary dials or touch calling units. Power for operating the totalizer is so low that it can be derived from the telephone line with no penalty of loop length and no adjustments are required. As indicated previously various modifications of the circuitry of the present invention permit operation of the associated coin telephone in prepay, semipostpay and emergency calling modes.  
 BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic circuit diagram of an electronic totalizer, adapted for inclusion in a coin operated telephone intended for operation in the prepay mode.  
  FIG. 2 is a schematic circuit diagram of an electronic totalizer adapter for inclusion in a coin telephone intended for operation in the semi-postpay mode.  
 DESCRIPTION OF THE PREFERRED EMBODIMENTS Prepay Operation Referring first to FIG. I a totalizer in accordance with the present invention is shown in a coin telephone equipped for Prepay Operation. In addition to the totalizer, those portions of the coin telephone that are required for operation of the totalizer circuitry are shown. Other portions not required have been eliminated from the drawing of FIG. I to simplify the understanding of the present invention.  
  Shown as a portion of the coin telephone circuit are terminals T and R connected to a telephone line extending to a telephone central office, dial 101 containing dial inpulsing springs, transmission network 103, receiver 104 and a transmitter 105. In addition the coin telephone circuitry includes a switch hook 102 shown in its non-operated or on-hook&#34; position, coin relay and its associated coin trigger springs III and 112. Coin trigger springs 111 and 112 are shown in their normal position. prior to the deposit of any coins in the telephone. In addition the coin telephone circuit includes coin operated switches 113 and 114 which operate in response to the deposit of nickels and dimes respectively. It should also be noted that these two springs are also shown in their normal or pre-coin deposit position.  
  The totalizer 100 consists of a power supply portion including diodes 121 through 126 inclusive. resistors I31, 132 capacitor 133 and a zener diode 134. Also included in the totalizer 100 are a decimal decoder counter 160, which may be a standard integrated circuit counter used to count and store information relative to the quantity and value of deposited coins. The counter circuitry may take several forms that are well known and as such, the details thereof do not form a portion of the present invention.  
  Included in the totalizer and connected between the coin operated switches 113 and 114 is logic circuitry consisting of gate 150, inverter 151 and capacitors 152 and 153 which provide an input from the coin operated switches 113 and 114 to the decoder 160. The output of the decoder is connected by strap 16] to gate 172, whose output is coupled through capacitor 173 to a bistable rate relay having associated contacts 171&#39;, Also included in the totalizer 100 is an optical isolator device 140 which provides a reset function for the counter.  
  For a further understanding of the present invention a description of the placement of a telephone call in a coin telephone of the prepay type in accordance with the present invention will be described.  
  Initially the subscriber will remove his hand set not shown, containing transmitter 105 and receiver 104 from hook switch 102 causing it to complete a circuit for terminal T through dial 101, the transmission network 103, transmitter 105 and receiver 104, through the hook switch contacts 102, to terminal R. The loop is now closed to the central office preparing it for response to signals from the coin telephone.  
  At this time the subscriber wishing to place a call must deposit the proper amount of money in the coin slot of the coin operated telephone. It should be noted that in the present embodiment as shown, that the counter output 20 lead is strapped by means of strap 161 to the input of NOR gate 172. This strapping indicates that the initial or base rate for operation of the present coin operated telephone is 20 Other base rates may be established by connection strap 161 to one of the other terminals such as the 5 etc. outputs of counter 160.  
  Assuming now that the customer deposits first a nickel, coin operated switch 113 will operate momentarily, connecting ground to one of the inputs of NOR gate 150. This causes an output pulse from NOR gate 150 which is extended to counter 160 which normally has an output on the lead extending from the zero terminal lead. An output signal will now be present on the 5 output lead. Because it has no output connection, no signal will be extended to NOR gate 172. With the output signal being removed from the zero output lead, this will cause gate 172 to produce in a direction to cause operation of rate relay 170, which will be coupled to the relay by means of capacitor 173. Capacitor 173 will charge and current flow to the relay 170 will cease. Relay 170 being bistable will remain operated. At this time the operation of rate relay 170 will cause operation of its associated contacts 171 placing a short directly across the dial inpulse springs of dial 101 and opening the operating path for coin relay 110.  
  When the initial coin deposit was made coin trigger springs 111 and 112 also operated. Coin trigger spring 111 prepared an operating path to ground for coin relay 110, while coin trigger springs ll2 opened to remove a previously existing short circuit across the dial 101. This latter short circuit path includes strap 115. If the coin operated telephone of the present invention is normally of the prepay type, but equipped for emergency calling, strap 115 would not be present and the short circuit provided by that strap and the path through the coin trigger springs 112 would not be present. Permitting direct dialing of emergency numbers without depositing of coins.  
  Recalling that a 20 i total deposit is required before dialing can commence, the subscriber will now deposit a second nickle reoperating coin operated switch 113, and cause the advance of counter of 160 to produce an output on the 10 1 output lead. It should also be noted that coin springs 111 and 112 will stay operated after the initial coin deposit and therefore no further action takes place involving their circuitry at this time. At this time the subscriber deposits a dime operating coin operated switch 114. The resulting ground pulse through the circuitry of inverter 151 and associated capacitors 152 and 153 will cause NOR gate 150 to produce two output pulses to counter 160 causing it to advance its output from the l0 i to output terminal and from the 15 output terminal to the output terminal. Because strap 161 is connected between the 20 output terminal and the input of gate 172, NOR gate 172 will produce a zero output, causing rate relay 170 to restore clue to current produced by the charge stored in capacitor 175 flowing through relay 170 in a direction to cause it to restore. Afer the change of capacitor 175 has dissipated relay 170 will remain restored since it is a bistable relay. At the same time an output from counter 160 was extended to gate 172 the same output was also extended over a count inhibit lead back into the decimal counter 160 preventing it from operating further in response to deposit of any additional coins.  
  With the restoration of relay 170 a path will be completed from terminal T through break contacts 171 and through the light emitting diode that forms a portion of optical isolator 140 to coin relay 110. Because coin trigger springs 11] were previously operated a path is now complete from coin relay 110 to ground. Completion of this path prepares coin relay 110 for operation and extends ground over terminal T to the central office to advise the central office equipment that a proper amount of coinage has been deposited in the coin operated telephone. When rate relay 170 restored the short was also removed from across the inpulse springs of dial 101 by the opening of the make contact 171.  
  When the connection is established through contacts 171 from terminal T, to the light emitting diode of optical isolator 140, current from the telephone central office will cause the light emitting diode to operate, turning on the associated photo transistor also included in optical isolator 140. This operation will complete a path from battery to the reset lead of counter 160, causing it to reset to zero.  
  At this time the subscriber may now operate his dial to effect control of the central office switching equipment to complete a connection to a selected subscriber.  
  After the subscriber has reached his party and completed his call, he replaces the hand set including transmitter 105 and receiver 104 on hook switch 102 opening the connections to the telephone central office. Coin battery will now be returned from the central offree over the lead connected to terminal T through break contact 171, and the optical isolator 140 to coin relay causing it to operate at this time to collect the previously deposited coins. It should be noted that prior to the application of coin battery to the telephone line from the telephone central office, insufficient current was available for operation of coin relay 110, although sufficient current was available for operation of the light emitting diode that was included in optical isolator 140. Operation of the coin relay 110 restores coin trigger springs 111 and 112 to their normal position. At this time the coin operated telephone is fully restored to normal and is ready for placement of additional calls over its facility.  
  If after the subscriber has deposited one or more coins in the coin telephone, he decides not to complete the call, and the total of the coins deposited is not equal to the established base rate, the following sequence of events take place. To abandon the call the subscriber will place his hand set including transmitter 105 and receiver 104 in its normal position on hook switch 102 causing it to restore. The restoration of hook switch 102 opens the loop connection to the telephone central office, causing the central office telephone equipment to return coin battery over the lead connected to terminal T. This coin battery is conducted from terminal T through neon diode 175 and resistor 174 to the optical isolator and particularly to the light emitting diode that forms a portion thereof, and from there to coin relay 110 and through coin trigger springs 111 to ground. Application of coin battery over this path causes operation of the photo transistor that is included in the optical isolator 140 which will cause application of potential to counter 160, causing it to reset back to zero. The operation of counter to its reset position causes an output on the zero terminal lead which through gate 172 and capacitor 173 will cause rate relay 170 to restore. The restoration of relay 170 completes a direct connection at break contacts 171 from the conductor connected to the T lead to the optical isolator 140. With the restoration of rate relay 170 and the restoration of it associated contacts 171, resistor 174 and neon diode 175 are no longer in the circuit, and sufficient current is available to cause coin relay 110 to operate. With the operation of coin relay 110 the previously deposited coins will be refunded and the present coin telephone returns to its normal arrival condition.  
  It should be noted that the totalizer circuit 100 derives its power directly from the telephone line connected to the telephone central office. A self contained power supply consisting of diodes 121 through 126, resistors 131 and 132 capacitor 133 and zener diode 134 provide a source of power for the circuitry of the totalizer.  
  To provide this power a connection from terminal T connected to the telephone central office through dial 101 is made to the junction between diodes 121 and 122 the return path is made from the terminal R connected to the telephone central office through resistor 131 to the junction of diodes 123 and 124. The four diodes 121 through 124 inclusive function as a full-wave rectifier whose output is utilized as required. The above outlined circuitry is employed power the totalizer circuit when the&#39;present coin operated telephone is in its normal or on-hook&#34; position.  
  When the telephone is in the operated or &#34;off-hook&#34; position the power is drawn from the telephone central office in similar matter except that a return path is also provided through resistor 132 which is connected between the junction of diodes 125 and 126, through operated switch hook 102 to the lead connected to terminal R. This additional path provides a higher source of available energy when the telephone hand set has been removed from the hook switch. It should be noted that in the present circuitry, a requirement exists that power be available from the telephone central office at all times in order to provide operating power for the totalizer 100. If totalizer 100 were not prepowered, it would be possible to operate the coin trigger springs and thus complete a call to the telephone central office with deposit of but a single coin of any denomination.  
  In the above description it should be noted that reference has been made to deposit of nickels and dimes to achieve the base rate required for operation of the present coin telephone. If a subscriber were to drop a quarter in the coin slot of the coin telephone, coin trigger springs 111 and 112 would operate, however counter 160 would not operate and accordingly the telephone would be in condition for placement of a call. This reflects the fact that a quarter is equal to or exceeds the established base rate requirement.  
 SEMl-POSTPAY OPERATION Referring now to FIG. 2 a totalizer in accordance with the present invention is shown in a coin operated telephone equipped for semi-postpay operation. The circuitry of the totalizer is similar to that of the previously described unit with three digit numbers beginning with 2 generally identifying circuit elements like those in FIG. 1 which begin with the digit 1. The telephone circuitry is also essentially similar except that a different form of coin relay is incorporated in the semipostpay form of coin operated telephone. The circuitry of the totalizer 200 for a semi-postpay coin operate telephone, distinguishes from that of the totalizer shown in FIG. 1 by its omission of two diodes 123 and 124 and associated resistor 131, optical isolator and the resistor-neon lamp combination 174 and 175 respectively. The remaining circuitry being identical to that shown in FIG. 1.  
  In the coin telephone circuitry it should be noted that the coin relay is a two coil unit consisting of coin relay coils 210A and 2108 each with separate associated spring contacts. Associated with coil 210A is double make spring contacts 216 while associated with coil 2108 are break contacts 217 and make contacts 218. A single coin trigger 211, is also employed in this embodiment. It should be further noted that coin relay 210 is polarized with coil A operating its associated contacts in response to reverse battery before coins are deposited and releasing after the first coin has been deposited. Coil 2l0B operates its associated contacts 217 and 218 after the first coin has been deposited and when reverse battery is present. The coin trigger 211 resets in response to normal battery conditions.  
  A subscriber wishing to make a call removes the hand set from the hook switch 202 which completes the loop to the telephone central office through terminal T, dial 201, transmission network 203 coin relay springs 217 and coin relay coil 210A, and then through the hook switch 202 to terminal R connected to the telephone central office. At this time dial tone is returned to the subscriber and the dial can be operated to establish the desired connection through the telephone central office.  
  When the connection is established to the dialed number, if the dial selection is to an operator or to an emergency number, reverse battery will not be returned and conversation may ensue in the usual manner. If however this is not a special service call of any sort on the connection being established, reverse battery will be returned from the telephone central office causing coin relay coil 210A to operate. This operation at contacts 216 places a direct short across transmitter 205 and a low impedance shunt through resistor 219 across the transmission network to prevent the subscriber utilizing the receiver 204 as a transmitter. If the called subscriber answers, the calling subscriber utilizing the present coin telephone will hear the answering subscriber via the receiver 204. On determining that he has reached the desired party, the coin telephone user will deposit coins having a predetermined total value equalling the established base rate in use for the present coin telephone.  
  Deposit of coins totalling or exceeding in monetary value the predetermined value established, will remove the low impedance shunt from transmission network 203 and the direct short across transmitter 205, so that conversation may ensue.  
  The details of operation of the totalizer circuit 200 can best be understood by the following description: initially assume that the calling subscriber has deposited a single nickel. In response to the deposit of the initial nickel, coin operated switch 213 will operate and through NOR gate 250 advance counter 260 from its zero output to the 5 9! terminal output position. Since no signal is available from that terminal and the output on the zero terminal is removed, the resulting output from NOR gate 272 through capacitor 273 will cause rate relay 270 to operate. Operations of rate relay 270 at contacts 271 prepares a shunt path directly across the transmission network.  
  Deposit of the initial nickel will also operate coin trigger springs 211 resulting in operation of coin relay coil 2108 and its associated contacts 217 and 218. When contacts 218 close the shunt path across the transmission network previously outlined affectively disables both receiver 204 and transmitter 205. At contacts 217 the operating path for coin relay coil 210A is opened causing contacts 216 to restore, preparing the transmission circuitry of the telephone for operation at such time as coins totaling in value the predetermined base rate have been deposited.  
  Deposit of additional coins whose monetary value is equal or greater than the 20 base figure. causes the counter 260 to advance and through gate 272 to cause rate relay 270 to restore. Restoration of rate relay 270 at contacts 271 removes the direct short across the transmission network. At this point conversation may ensue.  
  On completion of the call the subscriber will return the hand set to hook switch 202 opening the loop to the telephone central office.  
  When initial connection is made to the telephone central office, potential present at termainl T from telephone central office is conducted by way of the reset lead to the decimal counter 260. This potential is effective to automatically reset the counter 260 to its zero state. which will cause application at terminal zero of an output to gate 272 which through coupling capacitor 273 cause rate relay 270 to restore.  
  While preferred embodiments of the present invention only, have been shown, it will be obvious that numerous modifications may be made without deparing from the spirit and scope of the invention, which shall be limited only be the claims appended hereto.  
 What is claimed is:  
  l. A coin operated telephone instrument adapted for connection to a telephone central office by means of a telephone line, including a transmitter, a receiver, a calling device, a coin detecting mechanism normally inhibiting conversation between said instrument and a selected subscriber station of the type requiring deposit of at least one coin in said telephone instrument equivalent in total value to a predetermined value, said coin detecting mechanism operated in response to deposit of a first coin of any value to condition said instrument for conversation with said selected subscriber station, and a totalizer, said totalizer comprising: counting means electrically advanced once in response to deposit of each coin of a first value and electrically advanced twice in response to deposit of each coin of a second value, said counting means initially operated to generate a first output in response to a first advance and further operated to generate a second output in response to a predetermined number of additional advances; switching means connected to said counting means initially operated in response to said counting means first output to further inhibit conversation between said instrument and said selected telephone subscriber station, and further operated in response to said counting means second output to permit conversation between said instrument and said selected telephone subscriber station.  
  2. A coin operated telephone instrument as claimed in claim 1 wherein: said counting means further operation inhibits further advance of said counting means.  
  3. A coin operated telephone instrument as claimed in claim 1 wherein: said counting means comprise a decimal counter and logic circuitry, said logic circuitry operated in response to deposit of a coin of a first value to generate a single output pulse to advance said counter once, and in response to deposit of a coin of a second value to advance said counter twice.  
  4. A coin operated telephone instrument as claimed in claim 1 wherein: said switching means comprise a relay.  
  5. A coin operated telephone instrument as claimed in cairn 1 wherein: said coin detecting mechanism is operated in response to deposit ofa first coin of any value to prepare an operating circuit for said instrument, said switching means initial operation opening said operating circuit, and said switching means further operation completing said prepared operating circuit.  
  6. A coin operated telephone instrument as claimed in claim 5 wherein: there is further included reset means included in said operating circuit, operated in response to said operating circuit completion, to reset said counting means.  
  7. A coin operated telephone instrument as claimed in claim 1 wherein: said coin detecting mechanism initially completes a first shunt circuit around said calling device, and in response to deposit of a first coin of any value opens said first shunt circuit; said switching means initial operation completing a second shunt circuit around said calling device and said switching means further operation removing said second shunt from said calling device.  
  .8. A coin operated telephone instrument as claimed in claim 1 wherein: said coin detecting mechanism is initially operated in response to connection of said instrument to a selected subscriber station of the type requiring deposit of at least one coin in said telephone instrument equivalent in total value to a predetermined value, to complete a first shunt circuit around said transmitter; said switching means initial operation preparing a second shunt circuit around said transmitter and around said receiver; said coin detecting mechanism further operated in response to deposit of a first coin of any value, to complete said second shunt circuit; and said switching means further operation removing said second shunt circuit.  
  9. A coin operated telephone instrument as claimed in claim 8 wherein: there is further included reset means comprising a circuit connection between said counting means and said telephone line, said reset means operated in response to connection of said instrument to said central office, to reset said counting means.