PRE-PAID CELLULAR TELEPHONE SYSTEM

A pre-pay service unit uses pseudo-numbers to identify subscribers and substitutes actual numbers to complete a call after verification of authenticity and verification of a positive balance in a subscriber's account. The service unit and the cellular telephone exchange data in the process of authentication. For outgoing calls, a cellular telephone first transmits an "800" number and an ANI. The "800" number is the telephone number of the pre-pay service unit, which then requests number actually dialed. The cellular telephone responds with dialed digits, a security code, and status data. If the information is correct, the dialed digits are then passed to a local exchange carrier to complete the call. For incoming calls, a pseudo-number directs the call to the pre-pay service unit, which converts the pseudo-number to the actual telephone number of a subscriber's cellular telephone.