Evolution of PrePaid Service towards a real-time payment system

One of the main aims of Bell Core's intelligent network approach in the 1980s was to offer a generic solution for the deployment of value-added voice services within circuit switched networks. Although the INAP protocol always allowed the provisioning of number translation services by controlling the call set-up and influencing the routing of voice-calls it is another class of IN services which gained more and more importance. Today, the number of services which include additional control of the voice-call charging is by far the largest in number: Freephone, Premium Rate, Friends and Family, Home Zone Billing are just a few examples, and the most popular service has become a synonym for the whole IN architecture - the PrePaid Service (PPS).