In a simple laboratory on this site, 202 Green Street, Philo Taylor Farnsworth, U.S. pioneer in electronics, invented and patented the first operational all-electronic "television system" on September 7, 1927. The 21-year-old inventor and several dedicated assistants successfully transmitted the first all-electronic television image, the major breakthrough that brought the practical form of this invention to mankind. Further patents formulated here covered the basic concepts essential to modern television. The Genius of Green Street, as he was known, died in 1971.

California Registered Historical Landmark No. 941

Plaque placed by the State Department of Parks and Recreation in cooperation with the Philo T. Farnsworth Foundation, Inc., September 15, 1981.