Provided is a method and apparatus for enhancing a data transfer rate by adding a new data transfer channel using a differential signal to a conventional MMC. The method includes steps of determining whether a host controller is a host controller for a high-speed multimedia card; determining whether a multimedia card is a high-speed multimedia card; transferring data using a VDAT channel if the host controller is a host controller for a high-speed multimedia card and the multimedia card is a high-speed multimedia card; and transferring the data using a DAT channel in the other cases. A host controller for controlling a multimedia card configures a VDAT channel capable of transferring a differential signal using a reserved terminal of a conventional multimedia card and a newly added terminal, and includes a data channel selection unit for using the configured channel.