I have a homeline with Flip and was previously with Slingshot which is where I got my phone number. Whenever my parent rings me on a toll call I hear a single beep, like the sound you get when someone is pressing one of the numbers on the phone when dialing. I hear it on my end but the caller can't hear it on theirs and it happens quite a few times during the conversation but I'm not doing anything to cause it.
I don't have call waiting or any other services set up with my phone as I mainly just use it for broadband. It doesn't do it with local calls. I've bought a new handset, the batteries are charged, just can't figure out why it happens. Does anyone have any idea what could be causing it? It did it when I was Slingshot as well.