Abstract: Each potential user of a telecommunications network is assigned a single credit card containing at least first and second authorization codes, the first code being indicative of status as an authorized user of the telecommunications network and the second code being indicative of status as an authorized purchaser of goods and/or services, as in a conventional credit card. The authorization codes are preferably contained on the card in both human readable form, such as embossed lettering, and in machine readable form, such as magnetic encoding. The validity of the first authorization code is verified to permit access to the telecommunications network. After the telecommunications network has been used to complete a call, billing information including the first billing code that has been recorded locally is transmitted via the telecommunications network to a remote data base in which the second billing code associated with the first billing code is automatically determined in data processing equipment.