Doors, Knocking on
Always knock on the door before entering a room.
If there is no door, or if knocking on the door will cause it to open knock on the door frame.
Do not cross the threshold of the room without being invited in. Knocking alone does not give you permission to enter a room.
If the occupant of the room says the need a minute, give them five.
Always, Always knock on the door before entering a room.