1893 - Thomas Edison received two U.S. patents. The first was for a "Cut Out for Incandescent Electric Lamps" and another for a "Stop Device" (No. 491,992-3). Also No. 492,150 for "Process of Coating Conductors for Incandescent Lamps."
... prove more difficult to circumvent, including copy-prevention codes embedded in broadcast HDTV signals and the Palladium operating system. A wide variety of DRM systems ...