Pre-paid telephone calling card service implemented via switch-based intelligent network

An improved implementation of pre-paid telephone calling cards uses a switch-based intelligent network (IN) for automated processing of pre-paid calling card account transactions. Calling card account number, corresponding PINs, account status information and others are stored in tables maintained by one or several switches for routing calls, each switch nominally including a Service Switching and Control Point (SSCP), an Originating Call Processor (OCP), and a Terminating Call Processor (TCP). In the preferred embodiment, each switch also contains an Operator Service System (OSS) for allowing a telephone operator to direct call processing either by choice of the customer or as backup to the automatic processing capability of the SSCP.