GB1565445A - Prepayment telephone apparatus - Google Patents

Description

(54) PREPAYMENT TELEPHONE APPARATUS (71) We CSELT - CENTRO STUDI E LABORATORI TELEGOMUNICAZIONI S.p.A., of Via Guglielmo Reiss Romoli, 274, 10148 Torino, Italy, a joint stock company organized under the laws of Italy, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to prepayment telephone apparatus.

It is well-known that with the considerable growth in telephone traffic, it is considered desirable to provide ever greater numbers of public prepayment telephone apparati and, at the same time, to modify the characteristics of such apparatus so that it can fit in with new switching and transmission techniques and to other new operating requirement.

Of particular importance is the setting up of international or intercontinental subscriber-dialled trunk calls by means of prepayment telephone apparatus. Present telephone apparatus is inadequate for this type of service, as it compels the user to provide himself with an enormous number of tokens or coins the frequent collection of the individual ones of which would disturb the conversation; moreover, the token or coin storage capacity of present prepayment telephone apparatus is generally inadequate for dealing with such large payment collection.

To overcome such disadvantages telephone apparatus should be able to accept high value coins or tokens and, at the same time or alternatively, other payment means such as banknotes, bankcards and subscription cards. The acceptance of high value coins and other payment means requires that the telephone apparatus be able to ensure an optimum refund of unused amounts of money, consistent with the payment means deposited in the apparatus.

Among new technical advances it is worthwhile to mention the possibility of providing apparatus which enables number selection by more rapid and reliable keying (or dialling) than hitherto even when the apparatus is to be connected to an exchange not yet equipped for the type of number selection employed in the aparatus.

It is also necessary to consider various other operating requirements such as discriminating local calls from trunk calls either for statistical or for charging purposes: the availability of charging local calls by time, on the basis of various types of signal criteria, i.e., independently of the type of exchange to which the apparatus is to be connected.

The solution of the technical problems arising from such new characteristics required for prepayment telephone apparatus involves the utilization of means able to perform complicated logic operations.

Recent devolpment of logic circuit technology renders it convenient to decentralize as far as possible the execution of such logic operations to the site of the apparatus instead of making use of large centralized units which would produce serious problems of cost and operating flexibility and which could not be used to their optimum capacity due to the territorial dispersion of the apparati at the public's disposal.

To try to solve the above mentioned problems, various types of telephone apparatus have been proposed using electromechanical logic means, or hard-wired discrete component logic means or small-scale integration logic means or logic means using large-scale integration components planned and constructed individually for each kind of use.

The first of such proposed solutions, which is commonly adopted for present day prepayment telephone apparatus, does not allow the provision of logic means of sufficiently large processing capacity, due to the relatively low speed and large dimensions of electromechanical devices.

Although the use of discrete component logic means or small-scale integration logic means is more satisfactory from the viewpoints of dimensions and speed, there are problems of energy consumption, as it is not feasible to provide a remote supply of energy for logic means of these types when they are to have large processing capacities.

Logic means using large-scale integration components do not have the above mentioned disadvantages, but their realization is difficult and expensive, and above all, being hard-wired they are custom-built, and they do not allow that their mode of operation, which is fixed at the design stage, may be changed.

According to a first aspect of this invention there is provided prepayment telephone apparatus including a telephone and means for accepting payment both being connected to an on-site microcomputer having a stored program which is arranged to coordinate and control the making of, and payment for, a call via exchange-connecting means through which the apparatus can be connected to a remote exchange.

According to a second aspect of this invention there is provided prepayment telephone apparatus comprising a handset, interface means for receiving signals from a user of the apparatus, means for performing and monitoring the operations relevant to payment, and means arranged for transmitting signals to the user, each said means being co-ordinated and controlled by a built-in stored-program microcomputer operatively associated with exchange-con- necting means enabling the communication of the microcomputer with a telephone exchange to which the apparatus is to be connected, said microcomputer being arranged to perform the collection and the refund of payment means of different types and values, independently or simultaneously used, and having ratios of any value, and to establish the type of communication requested by the user via said interface means and to transmit relevant information via the exchangeconnecting means in accordance with both data previously stored in the microcomputer and data received during use of the apparatus.

An embodiment of this invention will now be described, by way of example, with reference to the accompanying drawing in which the sole figure is a block circuit diagram of prepayment telephone apparatus embodying this invention.

Referring to drawing, AT denotes prepayment telephone apparatus embodying the invention. The drawing provides only a schematic block diagram of the various units for generating or receiving signals to and from an exchange (not shown) or to and from the apparatus user, as the inven- tion only concerns such units. Neither the conventional mechanical structure of the telephone apparatus, nor its conventional wiring are shown.

MC denotes an "on-site" microcomputer forming part of the telephone apparatus according to the present invention and con sistine of a central processing unit, CPU, a pair of read-only memories ROM1, ROM2 in which the program of the microcomputer is stored, input and output units IN1, IiN2 U1, U2 and a timing device CK; the units CPU, ROMP, ROM2, IN1, IN2 U1, U2, whose functions will be described later, are connected to a common BUS 17.

The internal strutures of the units will not be described in detail since they can be derived straight-forwardly by one skilled in the art from consideration of their functions.

Reference numerals 1, 2 denote outgoing and incoming loops of a four-wire telephone line for the connection of the apparatus to an exchange. The provision of separate loops for the two directions enables the possible connection of the apparatus to four wire networks. The loops are arranged for conveying both signalling and speech, and also the direct current of the remote supply for the apparatus AT.

Signalling is effected using only alternating current, except for the out-of-service signal which is produced by interruption of the loops themselves. Signalling arriving at the apparatus is entirely out of band, while of the signalling leaving the apparatus the keyboard signals are in band, and all other signals are out of band; in particular the release and selection criteria, when the exchange does not allow the number selection by keying, are represented by suitable frequencies that are translated by a conventional repeating coil into conventional forme of exchange signalling.

AL denotes a normal feeder, able to convert the direct current from loops 1, 2 into the voltage necessary for the operation o' the logic circuits of microcomputer MC.

F1 denotes a conventional low-pass filter arranged to allow the transit of signals in the voice band from the loop 2; F1 is connected through a loop 3 to the receiver of handset MT.

F2 denotes a conventional high-pass ffl- ter, arranged to allow the transit of charging signals through loop 2 from the repeating coil (not shown) in the form of high frequency pulses (teletax signals).

Reference IN1 denotes a conventional gate provided with a plurality of connec tions providing access to the microcomputer MC and arranged to convert, to logic levels suitable for the operation of microcomputer MC, the alternating current signalling from the exchange through loop 2, filter F2 and connection 4. IN1 has direct access to BUS 17 through connection 5.

IN2 denotes a second gate provided with & plurality of connections providing access to the microcomputer and arranged to con volt, to logic levels suitable for the operation of MC, the signals intended for the exchange, through connection 6, from units TA, GA, S1, 52, LS of the apparatus AT and which will be described later. IN2 also has direct access to BUS 17, through a connection 7.

U1 denotes a conventional output gate provided with a plurality of connections and having direct access to BUS 17 through connection 8, and arranged to send through connection 9, suitable control signals to a signal generator GS whose function will be described later.

U2 denotes a second output gate arranged to send, through connection 11, appropriate signals to units M1, M2, FS, D2, FC, LS of the telephone apparatus as will be described later.

ROMI denotes a conventional read-only memory, connected to BUS 17 through a connection 12, and storing the programs of the microcomputer MC.

ROM 2 denotes a second read-only memory, connected to BUS 17 through a connection 13, and arranged to store data which is likely to undergo variation at a relatively high frequency as for instance data concerning the types and values of payment means to be used, the values of the charging pulses for local and subscriber trunk dialled calls, possible additional charges due for local and trunk dialled calls, taxes etc.

ROM 3 denotes a further read-only memory which can be plugged into BUS 17 through a connection 14 in order to enable supervision of, and diagnostics operations on, microcomputer MC.

D1 denotes a display unit which can be connected to BUS 17 through a connection 15 and is arranged to store data relevant to the operation of CPU and to deliver such data to maintenance staff external to the apparatus. a device for generating alter GIS denotes a device for generating alternating current signals and arranged to produce, in coded form, the user's signalling to be transmitted to the exchange, i.e., the sig nalling relevant to holding, disconnection and dialling;GS also generates the signals for enabling the repeating coil of the apparatus to accomplish statistical or com nzercial functions, such as, for instance, concerning statistics relevant to the number of local and trunk calls made, to the number of collection pulses, separately for local and trunk calls, to the number of coins or of other collected payment means, considered separately for each value, etc.

TA denotes a keyboard having, besides the usual keys for keying operations, some additional keys for direct emergency calls, for the repetition of a previously set up number selection and for enabling the user to demand settlement relating to payment, as will be described later. Such additional keys could be provided separately from the keyboard.

Reference GA denotes schematically the apparatus switchhook whose contact ga, enables the power supply distribution in the apparatus.

GE denotes schematically a plurality of units able to collect and store separately with regard to type and value all or some of the payment means to be accepted by the telephone apparatus. Such payment means can for instance be tokens, coins or banknotes, which, in the following description, will be referred to collectively as "coins".

The provision of the microcomputer MC enables the telephone apparatus to be free of restriction as to the different payment means and their relative unit values and can include fractions of a unit.

Unit GE will be referred to hereinafter as a "coin-box" since it corresponds generally to the paymentwollection device of a normal token-operated prepayment telephone apparatus.

S1 denotes a first conventional sensor unit arranged to detect the presence of coins in the coin-box GE and to inform the microcomputer MC about the respective numbers Of coins of each value. The unit S1 can also include a paper-money reader, if the telephone apparatus AT is to accept this type of payment.

S2 denotes a conventional second sensor unit, arranged to signal to the microcomputer the collection of coins and to indicate their respective values.

Double line arrows 18, 19 indicate connections between sensor units S1, S2 and the coin-box.

The signals transmitted by TA, GA, S1, S2 are sent to microcomputer MC through connections 6a, 6b, 6c, 6d respectively, which are included in a connection 6 to gate IN2. Connection 6 also includes a further connection 6e, through which are transmitted to the microcomputer, signals from a subscription card reader LS which may be provided. Such readers are known and may, for instance, be of a type able to read cards having a magnetised coded portion.

M1 denotes a device arranged to control the acceptance or collection of coins inserted into the coin-box GE, separately for each type and value. In the following description the device M1 will be referred to as a "collection magnet" similarly to devices accomplishing the same functions in conventional prepayment telephone apparati.

M2 denotes a device enabling a total refund of coins not collected and will be referred to in the following description as a "refunding magnet".

The connections between M1, M2 and the coin-box are indicated by double-line arrows 20, 21.

FS denotes a display unit arranged to signal to the user the out-of-order condition of the apparatus in the event of faults or irregular conditions of the electromechanical components of the apparatus or of the logic circuits of the apparatus (for example it may indicate coins not collected, or the full or other condition of the coin collecting receptacle, lack of power supply or of clock signal etc.).

D2 denotes a second display unit arranged to give visual indications relevant to the totalized debt or credit available in the apparatus and considering in total the allowed payment means. Obviously such indications will change with the reception of each charging pulse and the insertion of new coins.

Display unit D2 is also arranged to display the maximum value of coins inserted for a call, for purposes which will be described hereinafter.

FC denotes an acoustic monitor which may be provided to signal to the user that the end of the conversation time, corresponding to the deposited coins, is drawing near; the presence of FC is optional, as its functions can be accomplished by any device able to attract the attention of the user, for instance devices linked to the display unit D2 and able to cause a flashing visual indication delivered by said display unit.

Units M1, M2, FS, D2, FC receive control signals necessary for their operation, through connections lla, lib, lic, lid, and lle respectively, the latter together forming connection 11 to U2; also belonging to connection 11 is further connection lif which enables the sending of collection control signals to the card reader LS. This reader will be associated with units accomplishing functions corresponding to those of sensor units S1, S2 and of magnets M1, M2 associated with the coin-box GE. For the sake of simplicity such units have been incorporated in the unit LS for simplicity of illustration.

The operation of the apparatus will now be described with regard to a call originating from the apparatus. The case of incoming calls is not considered here since the apparatus is not primarily intended for this type of service.

When a user wishes to make a call, he first unhooks the handset so that the contact ga is closed and the different units of AT can be supplied with power.

On detecting the transition from the power-OFF position to the power-ON position, unit CPU of MC adjusts to zero all its registers and memories; it then checks for the presence of coins in the channels of the coin-box GE or for credit available by means of any subscription card inserted into LS.

The relevant information, delivered by unit S1 through connection 6c and by LS through connection 6e, is transmitted, through connection 6, to the input gate IN2, which then delivers it to processor CPU through connection 7 and BUS 17.

For the sake of simplicity, it will now be assumed that the payment is carried out only through "coins" as previously defined.

The case when a subscription card is used alternatively or additionally, will be con sidered later.

If sensor unit S1 signals to processor CPU that there is a lack of coins in the coin-box, CPU orders an indication of such condition on the display unit D2, through BUS 17, connection 10, gate U2 and connections 11, wild.

The lack of coins in the coin-box GE may indicate that the user wishes to make a call free of charge (for instance an emergency call) for which appropriate keys are provided on the keyboard TA.

It the user actually depresses a key corresponding to one of these calls the apparatus changes to the number selection stage, i.e., it sends to the repeating coil the accomplished keying, as will be described later.

However, if the user tries to key or dial a number corresponding to a call to be charged, the operation fails since processor CPU does not send to the exchange the information relevant to the number selection.

If the user wishes to make a charged call, he must insert a predetermined minimum payment into coin-box GE. When CPU receives from S1 the information relating to the number of coins of each value inserted into the coin-box, CPU calculates, on the basis of the data concerning the values of said coins as stored in ROM2, the total payment value deposited, and displays it on D2; moreover the highest value of those coins contained in the coin-box is displayed on D2.

If the total value of the deposited coins is at least equal to the amount of the shortest local call, processor CPU sends to GS, through BUS 17, connection 8, output gate U1 and connection 9, the order to send, on loop 1, to the repeating coil, a suitable 'holding" signal. Consequently the user receives from the exchange through loop 2, filter F1 and loop 3 the signal to start keying or dialling.

Thereafter, the user keys the first digit.

If this digit is 0. indicating that the call is to be a trunk call, CPU checks whether the credit due to payment deposited is greater than the cost of the trunk call of shortest possible duration and distance.

If the credit is less, the user is invited to insert further coins, for instance, by actuating a flashing visual indicator on the display unit 92 or by any other suitable means.

If, on the other hand, the credit is sufficient, unit CPU transmits to OS the order to send to the repeating coil, through connection 16 and loop 1, the keyboard frequencies or dialling pulses, always in the form of decades of cycles of alternating current at the frequency recognised by the repeating coil and in accordance with the code recognised by the exchange. The call is then set up in the normal way.

The procedure for the case in which the deposited payment is enough for a trunk call, is also valid in relation to a local call when the first dialled digit is not 0. It is assumed that the payment deposited is at least equal to the cost of a local call as otherwise the keying gives no result. Special services (first keyed digit 1) are considered to be charged on the basis of the rate for local calls.

When the called subscriber answers, different situations can occur depending on the type of charging provided for by the exchange. In particular, the exchange can either send a first charging pulse whose length varies according to whether a local or a trunk call is involved, or send a first pulse which is the same for any type of call. In this latter case the distinction between the two types of call takes place on the basis of the incoming frequency of the charging pulses, a frequency which in the case of a local call charged by time, will always be lower than the frequency of the charging pulses for a trunk call even within the shortest range of trunk call.

A clear distinction between the two types of rates is necessary because the rates to be put into operation for calls from public call offices may each include two portions, the first being a fixed charge that has to be paid for each call, and the second being proportional to the number of charging pulses and both the value of the first portion and the rate to be paid for each charging pulse may differ for the two tyDes of call.

Thus, assuming that the first pulse is different for the two types of call and that the apparatus can decide immediately what rate is to be effective, unit CPU calculates at each pulse the total debit (taxes included) which is deducted from the total credit and the remaining credit is displayed by unit D2.

The data necessary for performing such calculations are stored in the memory ROM2 so as to enable unit CPU to calculate the debits in terms of a preferred base unit of payment.

On receiving each charging pulse, unit CPU orders GS to send on loop 1, to the repeating coil, a signal acknowledging the reception of said pulse, indicating also whether a local or trunk call is taking place. This acknowledgement is, used both for statistical purposes and for checking the operation of the apparatus and its non-reception is interpreted by the repeating coil as a fault, with the consequent putting outof-service of the telephone apparatus AT.

The out-of-service condition is signalled to the user by device FS, activated by suitable signals sent from unit CPU through BUS 17, connection 10, gate U2 and connections 11, lic, As soon as the debt accumulated for the call reaches the value of the highest value coin deposited in the coin-box GE, CPU sends a collection pulse to magnet M1 through BUS 17, connection 10, gate U2 and the connection 11, 1 la.

The coin collection, detected by sensor unit S2, is signalled to CPU through connections 6d and 6, gate IN2, connection 7 and BUS 17; CPU in turn orders GS to send the repeating coil a signal informing the coil that a coin having a certain value has been collected.

The non-reception by CPU of the signal generated by S2 or the non-reception by the repeating coil of the signal from GS, informing it about the collection of a coin during a call giving rise to at least one charging pulse, it is interpreted as a fault in the apparatus which is consequently put out-of-service.

The coin collection does not involve any variation in the indication of the available credit provided on the display unit D2 since this indication is updated at the reception of each charging pulse.

The same operations are repeated for the collection of subsequent coins, the collection proceeding with the highest value coin first and successively lower value coins thereafter.

During these operations, unit CPU measures the time between successive charging pulses, starting from the second of such pulses in order to inform the user when the amount of the available credit is sufficient only for a further certain period, for in stance 10 sec., and to disconnect the call in advance (for example lsec.) of the ar rival of the first charging pulse at a time when the amount of coins deposited in the coin box would be insufficient for payment.

The user can be informed not only by the flashing of a visual indication on the display unit D2, but also may be informed by an acoustic monitor FC actuated by a signal coming from CPU through BUS 17, connection 10, gate U2 and connections 12, 1 le.

If the amount of the remaining credit is not sufficient to cover the amount that would be due for an entire interval between two successive charging pulses, the conversation time then allowed to the user is reduced proportionally, without waiting for the reception of the charging pulse due to occur after the deposited payment has been used up.

During the call, the user may add some coins to the coin box and consequently the indication of the credit available shown by D2 will be updated.

If the user ends his conversation when some credit is still available, two cases can occur, according to whether or not he wishes to make another call.

In the first case the user hangs up and almost immediately unhooks the handset again: consequently, the apparatus reverts to the initial conditions created by the handset being unhooked, without performing a payment collection operation nor varying the available credit indication.

For this call the operations of keying, charging and collection are caried out in the same way as for the previously described call, the only difference being that the initial debt will, ingeneral, not be zero.

On the occurence of the first changing pulse, any surcharge wil again be levied if the system provides for it.

On the other hand, if the user does not intend to make a new call, he has to replace the handset and depress the key for request of payment settlement, when the handset is replaced, unit CPU causes the transmission to the repeating coil, by OS, of a clear back signal, thus breaking the connection and preventing the sending of new charging pulses. Moreover, as a consequence of the operation of the payment settlement request key, unit CPU calculates, by a trial-and-error procedure, what combination of coins from those deposited in the coin-box GE, enables payment collection closest to the nearest base unit above the outstanding debit. This calculation is rounded up to comprise a whole number of the smallest coin in circulation, even if the calculation of the debt by means of the charging pulses is carried out to a greater degree of accuracy.

At the end of the calculation, in the "most unfavourable case" for the user, i.e., if only the highest value coin is greater than the total debit, unit CPU causes collection magnet M1 to collect one of the coins of highest value deposited in the coin-box.

The unused coins are refunded automatically (when payment collection is complete) by the refunding magnet M2 which is actuated by a suitable control signal from CPU through BUS 17, connection 10, gate U2 and connections 11, llb.

These payment-settlement operations are also performed automatically if a certain time interval elapses ("guard time") from the handset being replaced without any settlement-request being received from the user.

Moreover, during the guard time, in order to enable the user to try to avoid the "most unfavourable case" where the highest value coin is to be collected, the user can still add coins of lower denomination so as to enable the apparatus to optimise the rounding off.

On completion of the payment-settlement operations the supply is disconnected and the apparatus returns to its inactive state.

The preceding description above concerns the case in which unit CPU, upon receiving the first charging pulse, is able to establish whether the call must be charged as a local call or as a trunk call.

However, in the event that the first charging pulse does not distinguish between the two types of call, unit CPU presents to temporarily apply the local rate; moreover, it temporarily inhibits the sending to the exchange of the signal acknowledging the arrival of the first charging pulse since CPU is not able to add to said signal the indication of whether the call is local or trunk.

Instead, CPU checks whether the first keyed digit is an O. If so, CPU presents to apply the trunk rate, but otherwise, CPU postpones any decision and measures the time between the first and the second charging pulses.

If the time is less than or equal to the interval corresponding to the longest trunk pulse period, then, on arrival of the second charging pulse, unit CPU puts the trunk rate into operation. If on the other hand a time longer than said longest trunk pulse period elapses without a charging pulse being received, CPU calculates the debt on the basis of the local rate.

This latter condition also occurs when the first keyed digit is 1, i.e., in the case of a call for special services whose charging is to be on the ground of the local rate, or when the user breaks the connection before the arrival of the second charging pulse and before the expiry of the minimum time necessary for establishing whether it is a local or trunk call.

As soon as unit CPU is able to establish the rate to be applied, the acknowledgement of the charging pulses, checked temporarily awaiting the decision on the charging rate, is sent to the repeating coil.

The operation of the apparatus then proceeds as described above for the case where the first charging pulse distinguishes between the two types of call.

So, far it has always been assumed that local calls are charged by time. If however, the local network provides for the charging by means of a single pulse, it is still necessary to establish that the pulse is transmitted either when the called subscriber answers or at the end of the call. The first case is equivalent to the situation when charging by time in which the user breaks the connection before the arrival of the second charging pulse.

In the case where the charging pulse is transmitted at the end of the call, after the connection has been broken, CPU waits for the time necessary to allow the arrival of the charging pulse; if the latter arrives, payment-settlement and collection operations are performed on the basis of the local rate and otherwise the apparatus remains in a state awaiting the payment-settlement request.

In the event that the call fails (for instance because the called subscriber is engaged) the calling user can ask for the automatic repetition of the call by depressing an appropriately provided key on the keyboard TA after replacing and removing the handset and after receiving the start dialling signal.

Unit CPU, upon receiving the repition request from the keyboard TA automatically sends to the exchange the keyed digits which have been stored.

If the call the succeeds and the connection is made, the subsequent operations are as described above.

In the description above it has been assumed that payment is made only by mean of coins.

When the apparatus is arranged to ac cept payment by subscription card, after natively or in addition to payment by coins the operation of the apparatus is substantially the same as described above except that the card reader LS delivers to CPU through connections 6e, 6, gate IN2, connection 7 and BUS 17 information concerning the number of payment units made available by the card (this value is stored in ROM2), so that CPU can take it into account in carrying out the necessary checks before sending the holding criteria signals to the exchange.

During payment colection, if the card is the only payment means, LS annuls one or more of the credit units whenever a collection control signal comes from CPU through BUS 17, connection 10, gate U2 and connections 11, llf. LS also sends a signal to CPU concerning the annulment and the number of annulled units.

In the case of the simultaneous presence of subsciption card and coins, the payment collection is carried out on the basis that if the payment collection is to take place during the call, the single highest value payment means (coin or card credit) is collected. In the case of payment settlement, the most suitable combination of payment means will be collected.

The reader LS is equipped with means for enabling the continuation of the call, when the credit from one card becomes exhausted, by the insertion of a new card.

In the case of subscription card paymentcollection, the failure of the card reader LS or CPU to send a signal confirming the payment-collection, gives rise to the putting out-of-service of the apparatus.

The out-of-service condition is not only caused by the failure of payment-collection, but may also be, a consequence of lack of power supply, or the absence or over-filling of the receptacle for collected coins. These are common to most types of prepayment telephone apparatus as reasons for putting the latter out-of-service. Other reasons which arise in the case of the apparatus described above, for instance, the absence of timing signals from the clock CK are due to the presence of the microcomputer MC. The procedure by which the out-of-service condition is signalled to the user by CPU has already been described.

To facilitate workshop testing and inspection and testing during operation of the apparatus, there is provided the possibility of plugging into BUS 17, through connection 14, the read-only memory ROM3. The contents of the latter can consist of a program for reading all the registers of CPU.

ROM3 is arranged to be addressed periodically by CPU during the use of the main program: if ROM3 is present (plugged into BUS 17,) the program of ROM3 is carried out and the contents of the registers of CPU are sent, through BUS 17 and connection 15, to the display unit D1, where they are stored till the next reading. Thus maintenance staff can follow, from unit D1, the operation of all the registers of CPU and intervene in the case of anomalous operation. If ROM 3 is not present, CPU merely resumes execution of the main pro gram.

WHAT WE CLAIM IS:- 1. Prepayment telephone apparatus including a telephone and means for accepting payment both being connected to an on-site microcomputer having a stored program, which is arranged to co-ordinate and con trol the making of, and payment for, a call via exchangeconnecting means through which the apparatus can be connected to a

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (13)

**WARNING** start of CLMS field may overlap end of DESC **. awaiting the decision on the charging rate, is sent to the repeating coil. The operation of the apparatus then proceeds as described above for the case where the first charging pulse distinguishes between the two types of call. So, far it has always been assumed that local calls are charged by time. If however, the local network provides for the charging by means of a single pulse, it is still necessary to establish that the pulse is transmitted either when the called subscriber answers or at the end of the call. The first case is equivalent to the situation when charging by time in which the user breaks the connection before the arrival of the second charging pulse. In the case where the charging pulse is transmitted at the end of the call, after the connection has been broken, CPU waits for the time necessary to allow the arrival of the charging pulse; if the latter arrives, payment-settlement and collection operations are performed on the basis of the local rate and otherwise the apparatus remains in a state awaiting the payment-settlement request. In the event that the call fails (for instance because the called subscriber is engaged) the calling user can ask for the automatic repetition of the call by depressing an appropriately provided key on the keyboard TA after replacing and removing the handset and after receiving the start dialling signal. Unit CPU, upon receiving the repition request from the keyboard TA automatically sends to the exchange the keyed digits which have been stored. If the call the succeeds and the connection is made, the subsequent operations are as described above. In the description above it has been assumed that payment is made only by mean of coins. When the apparatus is arranged to ac cept payment by subscription card, after natively or in addition to payment by coins the operation of the apparatus is substantially the same as described above except that the card reader LS delivers to CPU through connections 6e, 6, gate IN2, connection 7 and BUS 17 information concerning the number of payment units made available by the card (this value is stored in ROM2), so that CPU can take it into account in carrying out the necessary checks before sending the holding criteria signals to the exchange. During payment colection, if the card is the only payment means, LS annuls one or more of the credit units whenever a collection control signal comes from CPU through BUS 17, connection 10, gate U2 and connections 11, llf. LS also sends a signal to CPU concerning the annulment and the number of annulled units. In the case of the simultaneous presence of subsciption card and coins, the payment collection is carried out on the basis that if the payment collection is to take place during the call, the single highest value payment means (coin or card credit) is collected. In the case of payment settlement, the most suitable combination of payment means will be collected. The reader LS is equipped with means for enabling the continuation of the call, when the credit from one card becomes exhausted, by the insertion of a new card. In the case of subscription card paymentcollection, the failure of the card reader LS or CPU to send a signal confirming the payment-collection, gives rise to the putting out-of-service of the apparatus. The out-of-service condition is not only caused by the failure of payment-collection, but may also be, a consequence of lack of power supply, or the absence or over-filling of the receptacle for collected coins. These are common to most types of prepayment telephone apparatus as reasons for putting the latter out-of-service. Other reasons which arise in the case of the apparatus described above, for instance, the absence of timing signals from the clock CK are due to the presence of the microcomputer MC. The procedure by which the out-of-service condition is signalled to the user by CPU has already been described. To facilitate workshop testing and inspection and testing during operation of the apparatus, there is provided the possibility of plugging into BUS 17, through connection 14, the read-only memory ROM3. The contents of the latter can consist of a program for reading all the registers of CPU. ROM3 is arranged to be addressed periodically by CPU during the use of the main program: if ROM3 is present (plugged into BUS 17,) the program of ROM3 is carried out and the contents of the registers of CPU are sent, through BUS 17 and connection 15, to the display unit D1, where they are stored till the next reading. Thus maintenance staff can follow, from unit D1, the operation of all the registers of CPU and intervene in the case of anomalous operation. If ROM 3 is not present, CPU merely resumes execution of the main pro gram. WHAT WE CLAIM IS:-

1. Prepayment telephone apparatus including a telephone and means for accepting payment both being connected to an on-site microcomputer having a stored program, which is arranged to co-ordinate and con trol the making of, and payment for, a call via exchangeconnecting means through which the apparatus can be connected to a

remote exchange.

2. Prepayment telephone apparatus comprising a handset, interface means for receiving signals from a user of the apparatus, means for performing and monitoring the operations relevant to payment, and means arranged for transmitting signals to the user each said means being co-ordinated and controlled by a built-in stored-program microcomputer operatively associated with exchangeconnecting means enabling the communication of the microcomputer with a telephone exchange to which the apparatus is to be connected, said microcomputer being arranged to perform the collection and the refund of payment means of different types and values, independently or simultaneously used, and having ratios of any value, and to establish the type of communication requested by the user via said interface means and to transmit relevant information via the exchange-connecting means in accordance with both data previously stored in the microcomputer and data received during use of the apparatus.

3. Apparatus according to claim 1 or claim 2 and including a telephone handset and an associated switch arranged for receiving and supporting the handset, said switch having a contact for enabling the distribution of power within the apparatus, the latter also including a keyboard enabling number-selection, said keyboard having keys for enabling the making of calls to be free of charge, for the automatic number-selection repetition of calls not yet charged, and for making a request for paymentsettlement at the end of a call.

4. Apparatus according to any one of the preceding claims and including a first collection unit arranged for collecting, separately according to type and value, payment means which are deposited in the first collection unit, said payment means including tokens and/or coins and/or banknotes.

5. Apparatus according to claim 4 and further including: a first sensor arranged to detect the presence of payment means deposited in said first collection unit and to send to the microcomputer up-to-date information concerning the numbers, type and value of said deposited payment means; a collection device arranged to effect the collection of said payment means separately for each type and value, upon receiving appropriate signals from the microcomputer; a second sensor arranged to send signals to the microcomputer indicating the collection of, and the value of, deposited payment means; a refund device aranged to effect, in response to a signal from the microcomputer, the automatic and simultaneous refund of all deposited payment means not collected after use of the apparatus.

6. Apparatus according to claim 4 or claim 5 wherein a second collection unit is provided and arranged for receiving payment by means of subscription card.

7. Apparatus according to claim 6 wherein said second collection unit is a card reader arranged to send to the microcomputer up-to-date information concerning the number of units of payment available from the card, to effect the annulment of one or more units for each collection order signal from the microcomputer and to send signals to the microcomputer indicating the annulment of payment units and the number of the annulled units.

8. Apparatus according to any one of claims 4 to 7 and further including: a display unit arranged to provide an onsite up-to-date indication of digital data concerning the total value of the payment means deposited and available as credit and the value of the highest value single pay ment means deposited in the apparatus.

a unit arranged to provide on-site indication of the out-of-serivce condition of the apparatus and means arranged to provide an on-site indication of the approach of the end of the conversation time corresponding to the value of the deposited payment means.

9. Apparatus according to claim 3 or to any one of claims 4 to 8 as appendant to claim 3 wherein the exchange-connecting means include an alternating-current signal generator arranged to generate coded signals for supply to the exchange and other signals concerning statisical data relating to the use of the apparatus, said exchangeconnecting means further including means arranged to discriminate from the signals from the exchange, those relevant to charging, and to transfer them to the microcomputer, said signal generator being arranged to send to the exchange, during numberselection by means of the keyboard, keyboard frequencies or signals corresponding to dialling pulses.

10. Apparatus according to claim 5 or to any one of claims 6 to 9 as appendant to claim 5 wherein said microcomputer is arranged to store charging pulses received via the exchange-connection means and to send to said collection device a collectioncommand signal whenever the debt for a call being made reaches the value of the highest value single payment means deposited, the microcomputer being further arranged to determine, in accordance with the value of the last single deposited payment means remaining, what conversation time remains available after the collection of the penultimate payment means, the microcomputer also being arranged to de termine, upon receiving a payment-settlement request signal, what combination of the deposited payment means remaining to be collected comes nearest to the outstanding debt after the call has ended.

11. Apparatus according to any one of the preceding claims and further including a memory which can be temporarily connected externally to said microcomputer and which contains test-programs enabling the reading of information concerning the execution of the logic operations being carried out by the microcomputer and indicating means which can be arranged to temporarily store and display said information being read from the microcomputer.

12. Prepayment telephone apparatus substantially as described herein with reference to the acompanying drawing.

13. A telephone system including an exchange and prepayment telephone apparatus according to any one of the preceding claims connected to the exchange via said exchange-connecting means.