We got FIOS installed a few weeks ago, triple play. My wife has had numerous issues where the call will drop and the person she is speaking with will hear what appears to be a fax-like computer tone just before it disconnects on their end. Called Tech Support. He suggested it could be the wireless phone system that we have. We have a 5.8 GHz Radio Shack / Uniden main base phone with extra extensions and the Verizon Wireless FIOS Router.
When they installed your system they placed a unit called the Ont. If you look at it there is a place called customer access. There you will find a telephone jack for your dialtone. If you plug a phone in that jack it disconnects your inside wiring in the house. This is a test point so you can determine if the trouble is with your phones or with our control unit.
As for the fax sound, do you have your lines wired to any electronic devices? Answering machines, computers, fax machines, cordless phones. I would eliminate those first.
If your problem still persist directly from the Ont, it's possible it may need to be replaced. Your next step after eliminating your wiring and phones is to call the FSC. The telephone number should be on the invoice the installer left with you.
Did you ever find a solution to the call drops? I too am having drops with the same sound occuring. Called Verizon and rec'd strange advice - to unplug all cordless phone chargers (not the base with the phone line - but the independent cordless phone chargers plugged into the wall electrical outlets). Then plug them back in one at a time. As crazy as this sounds I did it but it didn't work - I'm still getting dropped phone calls.
I've had no drop outs in the internet or fios tv - only the phone line.
What is the solution?