The front panel counter you describe as "AP" is actually (due to the limited LCD display) "RP" - it's checking the return path, trying to verify it has two-way

The front panel counter you describe as "AP" is actually (due to the limited LCD display) "RP" - it's checking the return path, trying to verify it has two-way communication - I.e. that it can send a signal back to the cable company. The counter will get to 53 if it sees suitable conditions, or give up at 52 if not.