Home Digital Phone makes it's own calls!

I have been looking at my Home Phone information on the AT&T (myAT&T) website. Specifically I am baffled by what I am seeing in the "Dialed Calls" section. Every few days, my phone is calling the same number own it's own. The calls last from a few seconds to a few minutes. The times are random but it is always the same number. I did a lookup of the number but no information can be found. Has anyone else seen this problem? My wife suggested that it might be the phone verifying a connection when our U-Verse drops out (which it does randomly for a few minutes at a time). Any help would be greatly appreciated as I am baffled.