An apparatus for and a method of transmitting a graphic signal generated by a graphic signal generation unit to a display unit. Compressed transmission data is generated according to a result of a comparison of a current graphic signal with a previous graphic signal and the transmission data is modulated together with predetermined header information. A reception interface unit restores the optical signal into the transmission data and header information and regenerates a graphic signal by decompressing the restored transmission data based on the header information. The transmission rate of data is reduced by the compression/decompression of the a graphic signal. Error correction encoding is provided to find and correct the error of data generated during transmission. A signal interference between channels, a delay of inter-channel transmission and electromagnetic radiation, which are generated by an electrical transmission method, are prevented. Long-distance transmission and external connections are simplified