This is the Virus and Securities forum, which I doubt either of which are causing your problem, perhaps you would get a better response from one of the Computer Help forums. This link here is for the "Communication and Messaging Forum".
I recently started using at&t fotr voip. I have comcast as my cable and internet provider. When I make or receive calls i get a lot of interference, and have to ask the person I am talking to to repeeat themselves many times. I am using a nise filter. Any sugestions as to how I can corect this.