A calling card system includes a public switched telephone network (PSTN) and a service selection gateway. The PSTN may receive calls from communication devices that may be either voice communication or data communication. The calls may be forwarded to the service selection gateway based on a calling card access number that is included in the call. Calls that are voice communication may be transferred to the PSTN or to a public network by the service selection gateway. The service selection gateway may provide voice communication transferred to the public network in a voice based network protocol such as VoIP that is transmittable over the public network. Calls that are data communication may be selectively transmitted over the public network in a data network protocol with the service selection gateway.