(aka Dimensional Gateway, Real World Interface)
In accordance with the Doctrine of Non-intervention, TARDISes are designed not to affect history. Because of this crew members normally can't alter history unless they leave the TARDIS. The Main Doors serve as the primary entrance/exit of a TARDIS's interior Micro-Universe. They are found only in the Primary or Secondary Control room. The physical space-time bridge between the interior and the Exo-Shell is achieved with differential layer-slippage to create the minimum of user involvement in the mathematical sub-structure.
When set properly the main doors can be voice activated and deactivated by saying "Doors." There is also a mechanical lever (officially known as Number 4 Switch.) on the console that can be used to open the doors. A properly coded remote energy impulse can also be used to open the doors if sent from inside the control room. They can be set to automatically close if no one is in the Control Room. If all power has failed, the Main Doors can be opened using the Emergency Door Control which is a large hand crank inserted into the wall to the left of the doors. The default settings for the force field can be programmed to allow the Main Doors to be safely opened even when the TARDIS is in Space. However it is impossible to exit through the doors without first shutting off the force-fields that protect the main doors. With access to a subject's biodata, it is possible to create an exclusion field that will automatically prevent that specific person from entering the TARDIS.
Normally it is possible to see the exterior environment through the open doors, however when in airlock mode there is a spatio-temporal void known as the atrium zone between the inner doors and the exterior doors on the outer shell. The inner and outer doors can act as an airlock that functions in vacuum or even under water. The atrium zone between the inner and outer doors is usually a black void, but it can be rendered in curved mirrors or the standard roundel pattern. When rendered as a black void the exterior doors can not be seen from the control room even though they are less then 2 meters away. Likewise those standing outside the TARDIS will be unable to see into it.
The Main Doors' interior (and exterior) size can be altered by up to 50% using the architectural software. This is done with a localized mass inversion wave, which returns the doors to a raw energy state. The Doors can be programmed to be a maximum of about 15 feet tall.
An Emergency Door located in the Power Stacks Room leads out of the opposite side of the Exo-Shell from the Main Doors. This Emergency Door also functions as a more traditional airlock. (For other emergency exits see Fail-safe.)
Dematerializing while the Main Doors are still open can result in a gravitational distortion that tries to dump everyone out into the Vortex to be disintegrated by the Time Winds. If the Door were opened while a TARDIS was travelling in the Vortex an emergency system would initiate an Automatic Emergency Landing, but this system can be overridden. If the Force Fields have been activated first, then the doors can be open while in the Vortex - though only a white void will be seen. If the doors open during a Re-materialization the dimensional space pressure would compress the dimensional stability of the interior, drastically shrinking the TARDIS and its crew. Possibly even to the point of being able to explore molecules. This dimensional compression would reverse itself when the TARDIS next dematerialized. For these reasons failsafes keep the TARDIS lock from being taken apart during flight (though this can be bypassed by disconnecting the Time Rotor).
The following color code is used:
- Black: For information from the TV Series, including Dimensions in Time, and 1996 TV Movie.
- Blue: For information from the Novels and Audios including Target, Virgin, BCC, and Big Finish.
- Green: For information from 'licensed' reference sources such as the Technical Manual, Doctor Who Magazine, and the Role Playing Games.
- Red: For information from unofficial sources -The Faction Paradox series, behind the scenes interviews, author's speculation, and popular fan belief.
The TARDIS Technical Index is copyright Will B Swift.