Operating voltage of a Flak installation

[Dufleuve]

Hello,

I have some components of a flak communication installation.

I know standard telephony uses 1,5v DC ; bunker telephones use 4,5v DC (correct me if wrong); vehicles are on 12v DC; planes on 24v DC.

I read that flak uses 36v DC, but I assume the actual operating voltage of the comms components (headphones, microphones, etc..) is lower.
Can anyone shed some light on this topic ?

Thanks