Patent ID: 7353993

Claim:
A host device configured to read and write information from and into a card and to supply a supply voltage that belong to a first voltage range or a second voltage range which is lower than the first voltage range, the host device configured to issue to the card a voltage identification command including a voltage range identification section, an error detection section, and a check pattern section, wherein the voltage range identification section includes information indicating which one of the first voltage range and the second voltage range the supply voltage belongs, the error detection section has a pattern configured to enable the card which has received the voltage identification command to detect errors in the voltage identification command, the check pattern section has a preset pattern, the device issues an initialization command including information instructing the card to initialize a memory that the card has, and the device changes the initialization command into a new memory initialization command including a section other than a voltage identification section depending on whether the device receives a response to the voltage identification command.