A Mark II TARDIS includes an Internal Monitor. This device detects the crystallization created by sapient biodata and thus allows someone in a control room to determine the number of sapient life forms inside a TARDIS. The exo-shell's Materialization Beacon can be set illuminate when there is one or more sapient being inside.
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.