Copycode

 We have become accustomed to a digital age when all data is forever, and can produce an infinite number of identical copies without loss and without the need for physical media (except the hard drive). In actuality this is very new. For the first century of recorded sound, every copy experienced generational loss. Actually for the first part of that century copies weren't even possible, each individual recording was an original, and it was decades before consumers could make dub audio at all.

As you know the record industry went through a phase trying to prevent the digital age, and has since compromised on futile attempts to just obstruct. I've written before on their attempts to do so with magnetic tape in the 1970s and early 1980s. Some of those efforts revolved around taxation. They made a related  attempt in 1987 by the RIAA to murder DAT tapes. You probably don't even remember DATs.

So the RIAA and related organizations but their weight behind a system created by CBS Labs. They would add an IC chip to the DAT recorder which scans the input signal. It's purpose is to  detect an "anticopy code" and respond by shutting off the record function for 30 seconds. The code consisted of a narrow frequency notch centered at 3840Hz. CBS called this "totally inaudible." The human range of hearing bottoms out around 20 Hz so this was a complete and total lie. 

On February 5, 1987 Senators Al Gore [D] and Pete Wilson [R] went for the gusto. They introduced the DAT bill which would have but that IC chip in every DAT recorder sold in the USA. The bill failed. Even President Regan opposed it. A second bill was proposed and it too failed. As the Clinton campaign ramped up in the Fall of 1991, Gore suddenly lost interest in the unpopular legislation. Over the following decade the DAT was simply replaced with wholly digital recording media. In 2005, Sony announced that its remaining DAT machine models would be discontinued. An era was over.