The Serial Copy Management System (SCMS)[1] is a DRM standard built into digital audio tech like DAT, MiniDisc, DCC, and consumer audio CD recorders. It works by adding just 2 bits — but no encryption or obfuscation whatsoever — to the digital audio signal that tell the recorder if further digital copying is allowed. Importantly, SCMS only ever blocked making a digital copy of a copy — you could always make a first-generation copy from an original, but not chain further digital copies. The requirement was pushed by copyright holders: in the US, consumer devices had to implement SCMS to ensure you couldn’t endlessly duplicate perfect digital recordings, but pro studio gear was exempt. SCMS doesn’t restrict analog copying, just digital serial copying. Most people found it annoying rather than effective.
The Serial Copy Management System (SCMS)[1] is a DRM standard built into digital audio tech like DAT, MiniDisc, DCC, and consumer audio CD recorders. It works by adding just 2 bits — but no encryption or obfuscation whatsoever — to the digital audio signal that tell the recorder if further digital copying is allowed. Importantly, SCMS only ever blocked making a digital copy of a copy — you could always make a first-generation copy from an original, but not chain further digital copies. The requirement was pushed by copyright holders: in the US, consumer devices had to implement SCMS to ensure you couldn’t endlessly duplicate perfect digital recordings, but pro studio gear was exempt. SCMS doesn’t restrict analog copying, just digital serial copying. Most people found it annoying rather than effective.
[1] https://en.wikipedia.org/wiki/Serial_Copy_Management_System