A method of operating a storage device includes receiving a first bit sequence including a request for changing a data rate from a host according to a first data rate through an input signal pin; sending a second bit sequence including a response to the request for changing a data rate to the host at the first data rate through an output signal pin; and changing the data rate to a second data rate according to whether a tail-of-burst (TOB) indicating an end of the second bit sequence is output.