The two columns monitor the state of individual bits which are required for the permit. If all the inputs are satisfied (or masked off), then all the bits will be shown as periods, and the Beam permit will say "Yes". Otherwise, individual bits will show up as asterisks, and the Beam permit will say "No".
You can look at details by clicking on the "individual module" above and toggling between 10 and 12.
As you see, under ordinary circumstances, the beam permit will drop if the horn supply is shut off. Because the horn supply is not part of the safety system, we have permission to mask off this input if the horn is being worked on and we still want to do beam studies. In this case, an "M" will appear next to input 4 on the MI-12 page. This should never happen during normal operation.