Slide the collar to unlock the coupler.
Slide the latch on the plug away from the coupler, then twist anti-clockwise to release.
Those are DIN connectors. DIN line-level signals expect a different impedance than is usual for RCA or XLR connections. IIRC you can put a resistor in series to convert to RCA.
I'm not sure what signal level and impedance DIN microphones use. I'll see what I can dig up.
It looks like this is a dictation microphone. One of the connectors allows you to ...