A data interface is provided for point-to-point communications between two devices, such as a read channel and a disk controller in an HDD system. An interface for communications from a transmitting device to a receiving device comprises a data bus configured to communicate m bits of data and a corresponding n bit data tag, wherein a given n bit data tag identifies a data type of a corresponding m bits of data on the data bus. An acknowledge signal from the receiving device optionally indicates that data on the data bus has been received and that the data on the data bus can be changed to a new value. A valid flag optionally indicates when a new predefined m-bit data value and corresponding n-bit tag value are on the data bus.