Method and apparatus for authorizing a calling card telephone call are described. In one example, a telephone calling card includes a planar body having a memory system, an input circuit, a controller, and a display. The memory system is configured to store key code information. The input circuit is configured to receive a personal identification number (PIN). The controller is configured to derive a key code from the key code information using the PIN. The display is configured to present the key code. The user may then use the key code for purposes of authorizing a call made using a calling card. The key code may change from time-to-time as the user uses the calling card. Since the user's PIN is not entered into a telephone by the user, the calling card is less susceptible to unauthorized and/or fraudulent use by third parties.