Not sure I understand what you mean by line might be blocked.

While the lines are idle, you can still selecting the blinking light/button and get dial tone from the station in question.

If the lines were blocked would you still get dial tone?

I will be on site tomorrow, so I can try your suggestion.

Any other ideas?
Is there a way to do a reset on at the individual port level?

I picked Saturday in case I need to take the system down. So I am open to anything.

thanks