You should check it out. But let me copy the opening paragraph here for all to see:
"Comcast Digital Voice Comcast Digital Voice is a Voice over IP service that provides unlimited calling and cool new features over our advanced broadband network - all without sacrificing any of your current phone features or the reliability and call clarity you expect. "
For reference, Voice over IP is VoIP. And for further reference the broadband network is the internet. Do you really work for them?