English: Parts of the Technics RS-M270X cassette deck. This 1981 model, built on the already outgoing M85 platform, was the company's first deck with dbx noise reduction. This is the rotary mechanical encoder for selecting the noise reduction mode. It does not switch signals directly; instead, it pushes or pulls a piece of flexible steel tape, using cams on the white rotating cylinder. The other end of the tape is connected to the actual remote switch. The blue plastic "filmstrip" holds and protects the steel tape inside. A striking example of fine mechanical engineering in the early 80s electronics. They already had affordable microprocessors, CMOS switches, and certainly relays existed for many decades... yet they would use a fairly complex mechanical link instead. Very soon, things would change and these mech things would gradually disappear