Vault sign

Description
The Vault 101 Sign is a type of sign found in Vault 101. These signs are either affixed to a location above a door, or to the ceiling with double sides. They identify a section of a floor or a particular room. Signs can be removed by the Maintenance Department by an order of the Overseer. Each sign has their own independent power source which powers the indicator lights and internal sensors which register movement.

These signs are labeled with black text highlighted by a green indicator light ('open door') or a red indicator light ('closed door'). Special use signs ('directional signs') are labeled with an arrow ('triangle') that indicates that the path to a section of a floor or a particular room lies beyond that door.

Signs are not always placed outside the room they are identifying. This is the case with the sign for the Systems Room where it is affixed to the ceiling inside this room.

History
These signs were used in Vault 101 from 2259 to 2277. It is not known if the signs were used prior to 2259. Sometime between 2268 and 2277, a directional sign to the Upper Level from Floor D, of the Lower Level, (see the survey) is removed.

Assumptions

 * "Signs can be removed by the Maintenance Department by an order of the Overseer." Who else would have the authority to remove a sign or would clear an alteration in the Vault?
 * "Each sign has their own independent power source which powers the indicator lights...". I base this assumption on the reasoning that since there no connector ports where the directional sign on Floor D had been, above the door, that the signs have a type of internal power that is independent of the Vault 101's power source.
 * "...internal sensors which register movement." I base this assumption on the observed action of the sign in the Atrium which is above the door blocked by a locker in 2277. The sign alternated between states of openness and closeness as the door attempted to close. As the sign is not connected to the door (see above), the sign must have a way to know if the door is open or closed. The easiest explanation is that the sign must have an internal sensor, maybe a sensor module.