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.

The NanoKey Fold has both USB-C and TRS-MIDI outputs, and comes supplied with a TRS-to-MIDI DIN adapter. There’s no Bluetooth connectivity - a cost-saving measure, perhaps? - but the keyboard ...