A time remaining determination module is implemented in a prepaid service to maintain and/or report subscriber account information based on accurately determined time remaining, even in light of replenishments using differing rate plans and/or dollar values. In particular, the inventive approach utilizes...http://www.google.de/patents/US20030008635?utm_source=gb-gplus-sharePatent US20030008635 - Time balance based prepaid subscriber database and reporting
