I don't use voice anyway - everything I do is through an app.
Check out jmp.chat - they route everything, your voice calls and SMS, through XMPP. So voice calls are VOIP. I don't even have conventional voice service with them.
Heaven forbid you have a fire or flood from a water line break. Insurance companies aren't your friend and will shaft you if they can - I've seen it happen with friends.
So now I have an inventory (and pictures). I have about 4x the stuff in my place than the average person in a house this size, so the defaults from insurance would make me lose lots of money. Once they see an exported spreadsheet with counts and dates (plus the pictures), they'll cut a check and not argue.
Plus the inventory helps me keep track of what I have so I don't buy it again.
AutoIt.
Just have it play a Windows ding sound every 4min, but also set the volume to zero first.
Have the script launch at login/startup.
AutoIt doesn't require an install, you can simply copy the script engine to a folder with your script. Been a while, but you may be able to compile your script with the engine too, so you have a stand-alone script.
Or make a silent, 1/4 second long wav/mp3, and use that to ensure you don't hear anything.
No kidding? I don't recall that.
First I read was in Windows NT mag about 1999,they had a working prototype, but without a touch screen.
Of course it wasn't called Android, yet.