Diodes D3-D5 are added for total USB interface protection. D3 is a common Schottky diode, and the rest (D4-D5) are 36V zener diodes. Finally IC1 (ATtiny85) is the master-brain of the mini development ...

I still have the power connector (DIN-6) for my first cassette recorder a Norelco Carrycorder or some such name. The original cassette. About the late 70’s I got a “high end” Pioneer car ...

In both cases, GND moved from pin 4 (on standard Type-A and Type-B) to pin 5, with pin 4 now used to support optional On-The-Go support. The Type-A variants of both of these smaller USB connector ...

The 5-pin DIN keyboard connector used with the first IBM PC (1981) and second-generation IBM AT (1984). It was subsequently replaced with the smaller 6-pin Mini-DIN connector on the IBM PS/2 in 1987.