Clock on box

Depends on the box. I think on some it acts as a activity light but on most it just blinks so it doesn't "burn in". Basically since that light would be on 24/7 they (box manufacturer) make it blink so it doesn't break.

If you have Trio (Contour) you can set it so the clock is only illuminated when the DVR power is on. When you turn the DVR off, the entire front panel goes dark.