A digital appliance, such as a digital camera, an MP3 player or a digital voice recorder, uses a memory card to store data. The appliance and the card use USB interfaces for appliance-card communication. When the appliance is connected to a host computer directly or via a passive USB cable, a switch within the appliance automatically establishes host-card communication for reading and/or writing data. In another embodiment, the switch can also connect the host to the appliance for configuration or operation. In another embodiment, the memory card temporarily stores data to be exchanged between the host and the appliance.