Roll Call is an emergency command that orders all Prisoners to stand in the doorways of their cells. This command can only be given during the night or during sleep regimes.
This command is useful at, potentially, pointing out any prisoners who are tunneling to freedom. Any prisoner who is digging an escape tunnel at the time, will turn up late to roll call, thus implying that they are digging an escape tunnel.
Guards in the nearby vicinity will notice a Prisoner's tardiness and will thereby automatically order a search of that cell. If no guards are nearby, the player must watch diligently for Prisoners are late to Roll Call and then order a search manually.
Prisoners will undoubtedly be irritated at the fact that they have been woken up in the middle of the night and will remain disgruntled until they are allowed to return back to sleep. Therefore, ensure that your Prisoners are not at Roll Call for any longer than that is necessary.
Note: This is a PC only feature, this is not on mobile or console