No, you do not need an internet connection but we do suggest an internet connection for dependable Series Recording. Without the internet, your program guide will provide limited guide data. From ~10hrs to ~4 days.
With the internet connected, most people will get 12-14 days of guide data for most channels.
CM-7500TB1 CM-7500GB16 CM7500GB16 CM7500TB1 CM-7500 CM7500