The Security department is ultimately responsible for ensuring the safety of both ship and crew. Their members care for people under arrest and the safety of guests.
Positions in the Department:
The Chief Security Officer is called Chief of Security. Her/his duty is to ensure the safety of ship and crew. Some take it as their personal duty to protect the Commanding Officer/Executive Officer on away teams. She/he is also responsible for people under arrest and the safety of guests, liked or not. S/he also is a department head and a member of the senior staff, responsible for all the crew members in her/his department and duty rosters.
The Assistant Chief Security Officer is sometimes called Deputy of Security. S/he assists the Chief of Security in the daily work; in issues regarding Security and any administrative matters. If required the Deputy must be able to take command of the Security department.
There are several Ship Security Officers aboard the USS North Carolina. They are assigned to their duties by the Chief of Security and his/her Deputy and mostly guard sensitive areas, protect people, patrol, and handle other threats to the Federation.
The Security Investigations Officer is an Enlisted Officer. S/He fulfills the role of a special investigator or detective when dealing with Starfleet matters aboard ship or on a planet. Coordinates with the Chief Security Officer on all investigations as needed. The Security Investigations Officer reports to the Chief of Security.
The Brig Officer is a Security Officer who has chosen to specialize in a specific role. S/he guards the brig and its cells. But there are other duties associated with this post as well. S/he is responsible for any prisoner transport, and the questioning of prisoners. Often Brig Officers have a good knowledge of forcefield technology, and are experts in escaping such confinements.
The Master-at-Arms trains and supervises Security crewmen in departmental operations, repairs, and protocols; maintains duty assignments for all Security personnel; supervises weapons locker access and firearm deployment; and is qualified to temporarily act as Chief of Security if so ordered. The Master-at-Arms reports to the Chief of Security.