Main Door Locking Mechanism
A TARDIS's Main Doors are protected by a double-curtain trimonic barrier, which is controlled by the Primary Threshold Systems. The lock is electronic and uses a meson projection and light refraction system to read the Trimonic Cypher-Indent Key to ensure that it has the correct crystalline molecular structure/code when compared to the lock's mathematical equation. If the code is correct, the Threshold Systems unlock the outer doors.
Another security measure is the "21 position lock." When it is enabled, the locking mechanism extends out of the shell and presents the user with 21 different key holes. If the wrong key hole is used, the whole mechanism fuses. Using the control console or properly programmed sonic screwdriver, the Main Doors can be Double-Locked (aka Deadlocked) from the inside. This prevents the Key from working in the lock. Double-Locking works even when the main and ancillary power is unavailable.
The TARDIS Lock can be jammed using a Laser Pencil tool (probably some type of Laser Cutter or a Laser Screwdriver). Goggles need to be used when operating the device at this power level. A jammed lock will have all of the combinations disabled so that no key will open it. If the lock has been jammed, then the operator can use his "stone with great power" (usually set into a piece of jewellery such as a ring or necklace) to refract light of a specific spectrum into the lock. This will open the door, but it is only a temporary fix and a Distrab from the TARDIS Tool Kit will be needed to field-strip and fully repair the locking mechanism. The entire locking mechanism can also be removed using the TARDIS Key. To remove or repair the TARDIS Locking Mechanism while in flight, the Time Rotor must be disconnected. This is necessary to override the fail-safes designed to prevent tampering with the lock while in the Vortex.
Normally a TARDIS's safety functions will not allow dematerialization while the Key is in the locking mechanism. But if the TARDIS is in Pause-Control, then inserting the key for more then 20 seconds will cancel Pause-Control and initiate dematerialization.
Type 53 and later TARDISES have Exterior Sensor Plates that the operator can be unlocked by holding the Key against the plate. Others used palm or retina scans. Some of the newer TARDISes built around the time of "Genesis of the Daleks" (Probably the Type 7-0-6) and those which have been upgraded have pure mind locks rather than key or touch activated ones. With this system the operator needs only to hold the key in his hand to lock or unlock the doors. This is usually accompanied by a chirping sound and a flash of the materialization beacon.[/tv[ Type 89 TARDISes (aka Type 102s) have locks with voice prints.
Attempts to pick the lock with primitive tools will result in an electric shock being delivered to the would-be intruder. Normally if someone tries to cut out the Lock, then a defence mechanism will destroy the saw blades in a flash of blue light. But operators should be aware, that if they divert all of a TARDIS's power to its drive systems it will be unable to activate is defence mechanisms. It would then be possible for intruders to breach the main doors. Under these circumstances and during other types of malfunction, the locking mechanism can be removed if someone has some simple electronic lock picking tools. With the entire exterior locking mechanism removed entry is impossible for the operator, even if they have the Cypher-Indent Key. For this reason, it is recommended that[/unoff[ the operator Double-Lock the doors when power is unavailable.
TARDIS keys are largely the same and it is fairly easy to use a key from one TARDIS to pick the lock of another TARDIS. This is because the total number of key/locks combinations available to TARDIS builders amounts to several dozen. With great difficulty, a TARDIS lock can be picked with a Sonic Screwdriver using the Devlin principle of randomized mathematical probability to generate the possible key combinations. A Tissue Compression Eliminator can also aid in neutralizing the locking mechanism. It is not unheard of for a TARDIS that has an exceptionally strong bond with its operator to be willing to open the door with a simple telepathic command. A being with incredibly strong psionic powers can force a TARDIS's Main Doors open from the outside. Such an attack would probably cause the Relative Continuum Stabilizer to fail. Powerful Rho Waves (of the sort used for hypnotic induction) have occasionally caused glitches making the ADM to double lock the doors.
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.