Voice and Data Modem

I'm renting XFI gateway from comcast TG4482A, its one of the new tall white towers. When I look at my device description on Xfinity website it labels it as Voice and Data Modem. I always thought that XFI gateway combines modem and router together so is my gateway both a router and modem? Cause it says voice and data modem but doesn't say anything about being a router.