I would think if the phone was in water, it wouldn’t ring at all.
Also, I’m wondering about the black boxes; Doesn’t the FDR have a transponder on it? Have they tried picking up the ping?
Teh FDR and CVR have an electronic sonic locator beacon that is activated when it contacts salt water. You would have to be quite close to hear the chirp. I would guess no more that a hundred yards or so.
It’s not a transponder. It’s a sonar pinger that is activated when entering the water. The recorders are also equipped with an emergency location beacon that transmits a signal on aviation emergency frequencies that is activated on ground impact. There are satellites that are designed to listen in on the emergency frequencies and determine their location. So the recorders have devices to transmit in the air and send out a sonar ping when in the water. Both are activated by an impact.