Anyway, I've identified the various connectors: DIN 45326 labelled as "Micro" DIN 45327 labelled with a headphone icon DIN 41524 labelled with a cassette icon. I'm assuming this is line-in.

The next generation of Brad mPm DIN valve connectors include Form C and Form Micro housings. Teaming IP67 sealing with an external-thread design, the components increase performance and ...