soo i have gotten a commodore 64 from a relative.... and it came with a weird little molex plug.... with a resistor connected to pin 1 and 6... the resistor pattern from pin 1 to pin 6 red red gold gold
It simulates a pressed button on a datasette. Some games (I remember the Leaderboard series) used such a plug as "copy-protection dongle" for their disk versions.