Wait, the lines indicate the channels!?

TIL

Nah the sleeves between the lines. The lines are just plastic rings meant to isolate sleeves.
Its the metal connectors between the bands/lines. 2 connectors = 1 signal (mono) + 1 ground 3 connectors = 2 signals (stereo) + 1 ground

3 connectors = 2 signals (stereo) + 1 ground

OR, positive + negative + ground

Could be balanced mono.