An imaging device receives from a host device image data and commands including a normal command and a real-time command to be processed prior to the normal command. A receiver receives a real-time processing disable command from the host device, and a processor processes the image data without processing the real-time command, even if the real-time command is included in the image data, after processing the real-time processing disable command. A method for so controlling an imaging device is also provided. The host controls transmission of image data and commands including normal and real-time commands as noted above to an imaging device. The host device comprises a detector that determines if data to be transmitted includes image data, and a processor that transmits the image data after transmitting a real-time processing disable command, if the detector determines that the data includes the image data.