The smart card or Subscriber Identification Module (SIM) card contains a microprocessor and a small amount of memory. With a SIM card, the subscriber can use any PCS (Personal Communication System) phone that has a card reader to make a call. The SIM card, the size of a credit card, is inserted into the PCS phone to activate the phone. In effect while the card is in the phone the PCS phone becomes personalised and becomes the user's personal phone. All the customer's personal data, personal identification number (PIN), services subscribed to, authentication key speed, dialing lists, and so forth are stored in the SIM card.