By coupling a rating engine with call processing, rating rules are generated that enable a flexible interface between call process and call rating without necessitating that fixed data be passed between them. The real time charging system (RCS) provides a process that creates a generic entity, called a bucket, and uses it to keep track of account information and/or to count types of usage. The bucket allows an operator to define accounts and usage counters and how they are used as part of the rating rules. Use of these buckets is defined in rating rules, thus turning control over subscriber account and usage counters to the network operator. Further, the RCS provides a calendar option for limiting times during which calls to general telephone numbers can be made or received.