Question : Computer rings like phone

When I am connected to my high speed wireless, about every 45 minutes  to 1.5 hrs, my computer rings a single phone ring like someone is trying to dial in to my computer. It only rings once but nothing happens. It will do this as long as my wireless is connected. Disconnect the wireless and it doesn't ring. At first I thought it was coming in on my fax line but the actual phone would not ring when the computer did. Disconnected the fax line - did not stop the single ring.

Answer : Computer rings like phone

Maybe it's just one of your sound scheme like everytime the pc is connected to the internet, it would play the ringing.wav.
So maybe about every 45 minutes to 1.5 hrs, your pc loses and reestablished connection?  Hence, the ringing.  Just a thought.

zd