I am running a small home business and have been looking into a voip service. After researching service providers I started researching phones. I am aware that most of these service providers offer phones that are compatible with their own service but I decided to search for something a little "cooler and sleek" looking. If I have to throw away some extra cash on it I am ok with the one time investment. Came across the Panasonic kx nt400! I've checked with a few service providers, 8x8 and nextiva, but neither of them support this phone. One, because they either don't support phones other than what they carry or two, it's not SIP compatible. The phone is an IP phone but now I am a little confused on the difference between IP compatible and SIP compatible?? Also, would anyone know of a small business voip service compatible with the phone? Thanks!