I don't believe it goes through the voicemail. As far as I know, no one is making the call. Earlier today, I had it happen. My phone rang, it said it was ext 110 (not the voicemail), and when I picked up, I got dial tone. The other users don't pay any attention to what happens, or they don't have any clue what is going on with it (not that I have a whole lot). I am fairly sure that it isn't going through the voicemail system, but is there any way to tell?