A memory card of one published standard, such as the Multi-Media Card (MMC) or Secure Digital Card (SD), is modified to include the function of a Subscriber Identity Module (SIM) according to another published standard. The controller of the memory card communicates between electrical contacts on the outside of the card and both the memory and the SIM. In one specific form, the memory card has the physical configuration of the current Plug-in SIM card with a few external contacts added to accommodate the memory controller and data memory. In another specific form, the memory card has the physical configuration of the current SD card, including external contacts.