X1 box channels on tv with SD service?

Upgraded to X1 box recently on a tv with only SD service at present (tv is HD capable but not signed up for HD service); using coaxial input to tv. Channels are showing up on tv as HD ones not SD ones? Ex. enter 2 for CBS and screen shows 802 for CBS. Go to Guide and it starts at 802 not 2. Why is this happening?