Hi!
So, I've recently gotten really curious about linkpearls and how they work (In a lore sense, not gameplay-wise). I've looked at the distributor and the cutscenes I remember.
So what I would conclude from that is:
1. They ring with that woap/boop-like sound, and it would appear that they have to be "answered" before any transmission of voices begin.
1.2 The answering seems to take place via the character raising their hand to their ear and doing.. Something.
2. The linkpearl appears to be in/on/by your ear.
3. When the character lowers their hand again, the transmission seems to end, so to me that hints that it's not a constant signal.

But the reason why I'm writing this topic is to hear what you guys have found/what your takes on it are, Comments are appreciated. Cheers