Channel 3 or 4. This will be determined by what is selected in the hardware settings of the set-top box (STB). (Many newer TVs have dedicated inputs that are not dependent on the TV channel.)
You might have the guide on the Subscribed, HD or Favorites list instead of the All List. Press Guide until you see ALL appear in the left corner of the guide. Or, you may need to check your parental controls. It is possible that certain channels are blocked and will not show up in the guide.