Abstract:
A method and arrangement for providing prepaid calling card services to a calling party is disclosed. Near the end of value of a prepaid calling card account, the calling and called parties to a connection are split and the calling party is given the opportunity to increase the value of his or her prepaid calling card account. If the account is increased the call continues using the increased value. Alternatively, if the account is not increased the connection is dropped.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to Intelligent Network Telecommunications and particularly to calling card services via such a network. 
     Calling card services are used in telecommunication systems primarily as a means to affect the billing for services. For example, a standard calling card may be used to change the party or account charged for the cost of a telephone call. Usually the change involves actually charging and billing an account represented by the calling card rather than an account represented by the calling telephone. Debit or prepaid calling cards may also be used to pay for telecommunication services. With a prepaid calling card the user prepays an amount of money to establish a card balance and as services are used the balance is decreased. When the balance becomes zero or less than the cost of a requested service the service is not provided or, if ongoing, it is terminated. When the service being provided is a telephone connection between parties the expiration of the prepaid calling card balance results in the termination of the connection. A need exists in the art for an improved manner of providing services from a prepaid calling card and particularly in the manner of terminating prepaid calling card services. 
     SUMMARY OF THE INVENTION 
     A system and method in accordance with the present invention announces the expected termination of a prepaid calling card before call termination. As such, the call originator and call terminator have the opportunity to close a conversation before the call connection is dropped. Additionally, and advantageously, the call originator may be given the opportunity to change the billing account for the call so that the conversation can continue based on a new prepaid amount. In accordance with the embodiments, the change of billing may result in changing billing from one prepaid calling card account to another or it may result in adding value to an existing prepaid account by means such as a credit card. 
     As described herein the parties to a prepaid calling card account are not just cut off when the prepaid amount is used up but the connection between the parties is split and a call originator is given the opportunity to change the prepaid amount available to continue the connection. 
     A method as described later herein comprises establishing in an Intelligent Telecommunication Network, a value identifying a prepaid amount for telephone services, establishing a connection between a call originator and a call terminator and timing a connection established. When the timing represents that the value has, or nearly has, been used up to pay for the connection, the connection is split and a warning tone or announcement is delivered to the call originator. Such a warning tone or announcement may also be delivered to the call terminator. Advantageously, the call originator may be given the opportunity to add value to the prepaid account by means of a credit card or by changing the billing account to another prepaid calling card. 
     Such conveniences are provided in a system comprising a service switching point of the call originator and a service control point of the telecommunication Intelligent Network. The service switching point collects digits necessary to identify the call terminator and to associate the call with a prepaid account against which the call is to be charged. The service control point receives the digits from the service switching point, associates the proper account with the requested connection and begins to time the connection against the associated prepaid account. When the account is used up (its value becomes 0) or nearly so, the service control point directs the service switching point to split the existing connection, connect a digit receiver and play an announcement to the call originator. The call originator may then dial digits defining another prepaid account against which to charge the existing connection. The service switching point then receives the digits and forwards them to the service control point which, in response thereto, associates the another prepaid account with the connection and reestablishes the connection between call originator and call terminator. Alternatively, the call originator, upon receiving the announcement of expiring prepaid calling card may dial digits defining a credit card which should be charged to provide additional value to the existing prepaid calling card account. After adding value, the service control point directs the service switching point to reconnect the call originator and call terminator and times the connection against the augmented value of the prepaid card account. 
     When operating as herein described, call originators can avoid being abruptly cut off from ongoing communications and are given opportunities to extend the communication by providing an account of additional value against which the communication can be charged. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A more complete understanding of the invention may be obtained from consideration of the following description in conjunction with the drawing, in which: 
     FIG. 1 is a block diagram representing a telecommunication Intelligent Network; 
     FIG. 2 is a flow diagram of a prepaid calling card service with warning announcement; and 
     FIG. 3 shows a message sequence for an embodiment. 
    
    
     DESCRIPTION 
     FIG. 1 is a block diagram representing a toll call between a call originator  101  and a call terminator  103 . Call originator  101  is connected to a local telephone switch  105  which operates in the manner well known in the art to receive signaling from call originator  101 , to provide announcements to call originator  101  and to provide basic telephone connection services to the call originator. Telephone switch  105  is sometimes referred to as a service switch point or SSP. Telephone switch  105 , which may for example be a No. 5ESS, is also connected to a toll network  107  and to one or more service control points (SCP) represented by SCP  109  which is also connected to the toll network  107  and other service switching points such as  111  which provide telephone service to the other subscribers such as call terminator  103 . 
     In FIG. 1, SCP  109  represents the intelligence and stored data of the Intelligent Network. The service control point  109  includes program and data which assist the SSPs  105  and  111  in providing extended services to the subscribers connected to them. For example, when call originator  101  wants to connect to call terminator  103 , the originator sends calling digits identifying the call terminator  103  to the SSP  105  which collects the digits and interprets them as defining a toll call. SSP  105  then forwards the collected digits to the Intelligent Network SCP  109  and requests a connection to the party identified by the collected digits. The SCP  109  identifies a path through the toll network  107  between SSP  105  and SSP  111  and notifies SSPs of the expected connection to call between call originator  101  and terminator  103 . SSP  111  responds to the possible connection by checking the status of call terminator  103 . If call terminator  103  is in use, SSP  111  notifies the SCP  109  which, in turn, notifies SSP  105  that call terminator  103  is in use. SSP  105  then sends the well known busy signal to call originator  101 . When the call terminator  103  is not in use SSP  111  sends a ringing signal to it and notifies SSP  103  of the ringing via SCP  109 . When call terminator  103  is not answered the ringing signals continue until call originator  101  hangs up. At hang-up the SCP  109  and SSP  111  are notified, all signaling stops and the identified toll network path is released for use by other connections. Alternatively, when call terminator answers the SCP  109  is notified and control signals are sent to the toll network  107  and SSP  105  to complete the talking connection between the call originator  101  and the call terminator  103 . Both SSP  105  and SSP  111  monitor the status of the connection and when either call originator  101  or the call terminator  103  go on hook notice is sent to the SCP  109  which directs SSP  105 , SSP  111  and toll network to drop the connection. 
     The network intelligence of the SCP  109  is also used to accumulate information from which subscriber billing can be created. The SCP  109  includes data representing the cost of calling for a plurality of subscribers such as call originator  101 . When an originator paid toll call is placed, the SCP  109  computes the cost per time of the call for the originator and then times the duration of the call. At call completion, a value is stored in a file associated with the call originator and representing the total cost of the recently completed call as well as other prior calls billed to the call originator. 
     Other types of call payment are also administered by the SCP  109 . For example, prepaid debit cards or calling cards are available which can be purchased for predetermined dollar amounts. Such prepaid calling cards may be purchased for $10, $20, $50 or other value and may have a preset calling rate such as 10 cents or 15 cents per minute. The prepaid calling card does not in fact represent an amount of money available to the purchaser at the moment of use but instead represents the identity of an account stored in the telephone network. When a prepaid calling card is purchased, the selling party must first “validate” the card. The act of validation establishes a money value file (account) on an SCP of the intelligent network represented by SCP  109  in FIG.  1 . That is, the value of services due to a purchaser of a prepaid card is represented by a data file in an SCP and not by the card itself. The card and codes printed thereon are used to associate the user of the card with the money valued data file. 
     When a call is placed using a prepaid calling card, the initial dialing of calling card digits associates the call with a particular money valued data file of the Intelligent Network as represented by SCP  109 . The call is completed normally, however, instead of accumulating costs to be charged later to the user, the ongoing costs of the connection are “subtracted” from the value of the associated data file until the data file represents no more value. At this point, the connection associated with the call is dropped and no readily available arrangement of continuing the connection exists. 
     FIG. 2 is a flow diagram representing the interaction between an SSP  105  of a call originator  101  and an intelligent network SCP  109  in the completion of a prepaid calling card call. The flow begins with a block  201  which represents the steps necessary to establish a prepaid calling card call based on an account value stored in SCP  109 . The processes of block  201  are well known in the art and are not described further herein. When the call connection is completed the cost per unit time is known and the SCP  109  computes in block  203  a total time available based on the value of the prepaid account. A timer is then started in block  205  for a period of time equal to or somewhat shorter than the maximum calculated time. In the present example, the timer is set to a time  20  seconds short of the maximum time. A step  207  is then repetitively performed to determine whether the time has timed out. Additionally, a block  209  is performed while the timer is running to identify if one or more of the parties have gone on hook or the connection has been otherwise disconnected. When a disconnect is deleted in block  209  the process continues by calculating in block  211  the cost of the call up the disconnect and subtracting that cost from the prepaid account associated for the current call with the call originator  101 . After step  211  the billing is ended and the adjusted account value is available for a subsequent connection. In the preceding description the timer and disconnect detection were shown performed as process loops. Other methods may also be used such as hardware or software timers and disconnect identifiers which interrupt or otherwise notify a call process upon the occurrence of an event. 
     When a time out is detected in block  207  indicating that the calling card amount is near zero, a block  215  is performed to split the call originator  101  and call terminator  103  connection in SSP  105  and a tone or other announcement is played in block  217  by SSP  105  to call originator  101 . Advantageously, the call terminator  103  is kept on hold. The tone or announcement in block  217  calls for a response from the call originator  101  to provide new prepayment value against which future parts of the connection (or subsequent connections) may be charged. In the present example, a simple distinct tone is played to which a knowledgeable user responds by pressing the pound (#) key, or any other predetermined key, if alternative payment is to be made. The pound key press is detected in block  219  and flow proceeds to block  221  to identify a source of new prepayment value. An announcement may be played in block  221  in response to the pound key to guide the user through the options for providing new payment value. In one option  223   a , the call originator provides the identify of another prepaid calling card account which is to be substituted for the about-to-expire account. Alternatively ( 223   b ), the call originator may provide a credit card number and an amount of money by which to increase the existing prepaid calling card account. After either block  223   a  or  223   b  has been accepted flow proceeds to block  225  where the connection in progress is coupled to the new prepaid value account for continued payment. The flow then returns to block  203  where a timer is set based on the new value and the call continues as before. When the call originator does not respond to the tone (announcement) of block  217 , flow proceeds from block  219  to block  229  where the parties are reconnected for the approximately 20 seconds remaining on the original prepaid calling card account. At the end of the short reconnect period the timer times out and the call is terminated with an announcement in block  231 . 
     FIG. 3 illustrates an embodiment of warning tone service using Intelligent Network Application Party Capability Set  2 . FIG. 3 is arranged as a message sequence “ladder” to show the messages flowing between SSP  105  and SCP  109  to implement the intelligent network service. The first three messages represented at lines  301 ,  303  and  305  consist of Initial DP service key (Initial Detection Point), Req Rep BCSME oDisconnect-R (Request Report Basic Call State Machine), and connection (Destination Routing Address) use the expected messages for setting up the stable two-party talking path represented at  307 . It is assumed that EDP (Event Detection Point)-9B is armed for the stable call. 
     When the prepaid billing timer in SCP  109  times out (block  207 , FIG. 2) SplitLeg operation is sent ( 309 ) to the SSP  105  directing that the stable call be split and that the passive party, i.e., call terminator  103 , be placed on hold. The splitting of the parties puts the connection from the SSP  105  to the call originator  101  in call segment  1  (CS 1 ) and the connection from SSP  105  to the call terminator  103  in call segment  2  (CS 2 ). While the split state continues, a CTR (Connect to Resource), PACUI (Prompt and Collect User Info) and PA (Play Announcement) are sent  311  to call segment  1  to notify and to collect new billing information from the call originator. If it is desired to advise the call terminator  103  of the call status, a CTR and PA may also be sent to call segment  2  to provide the announcement. Once the call originator digits have been collected and a proper prepaid billing account established for the call, a Merge Call Segments operation ( 313 ) identifying both the originating caller and the terminating caller is sent to SSP  109 . In response to the Merge Call Segments operation, the parties are rejoined to continue with a stable talking path. 
     It is understood that the above described embodiments are merely descriptive of the principles of the invention and that many variations may be devised by those skilled in the art without departing form the scope of the invention. It is intended that such variations be included within the scope of the claims.