Gallifreyan Timeships such as the Doctor's TARDIS sometimes displayed a voice interface. It enabled an occupant to interact with a responsive hologram - offering medical analysis and limited psychological counselling.
The interface spoke in a neutral, automated voice and would describe itself with "I am a voice interface," showing itself to be a distinct subroutine rather than the TARDIS's own consciousness speaking directly, (TV: Let's Kill Hitler) which was only possible in very rare circumstances. (TV: The Doctor's Wife)
By several accounts, the interface was programmed to take on the personality of the person it took on, rather than remaining impassive. When it seemed the Eighth Doctor was dying, the exploded TARDIS gifted him with the company of Liv Chenka and Helen Sinclair, so that he need not die alone. They responded exactly as the real Liv and Helen would. (AUDIO: Get Andy)
Features
The voice interface could be activated at a simple spoken request. But the main feature of the interface was the holographic avatar. It could take the form of anyone of the Doctor's choosing, (TV: Let's Kill Hitler) drawn from records kept in the TARDIS' memory banks. (HOMEVID: Meanwhile in the TARDIS)
It should not be confused with the actual TARDIS matrix, or soul, which only interacted directly with the Doctor once, after being placed in the body of a humanoid woman. According to the Doctor's TARDIS, she was not constructed to allow her actual matrix to interact through the TARDIS technology, (TV: The Doctor's Wife) an oversight which later models of timeship than the Type 40 would eventually correct. (PROSE: Alien Bodies)
Known interactions
The Doctor's TARDIS
Whilst infected with anti-time, the Zagreus infected persona of the TARDIS used the interface in the form of the Brigadier. After being restored to normal, the TARDIS used the interface to help Charley, Romana and Leela stabilise the Eighth Doctor. (AUDIO: Zagreus)
After the ship was critically damaged and the Eigiht Doctor left adrift in space in a failed attempt to rescue Andy Davidson from a crashing spaceship, the TARDIS used the voice interface in forms of Liv Chenka and Helen Sinclair to give the Doctor someone to talk to until the ship's air bubble ran out and he died. (AUDIO: Get Andy)
An interface in the form of the Tenth Doctor instructed Sally Sparrow and Larry Nightingale to use their DVD to pilot the TARDIS. (TV: Blink) In this form the TARDIS later warned the Doctor himself of the ship's inability to leave the time zone whilst being captured by Intersol, only for the hologram to be hijacked by Finn Dargo. (COMIC: The Crimson Hand)
When the Eleventh Doctor was poisoned by Melody Pond, he accessed the voice interface as he was too weak to reach the console. It first took the form of himself, but he swiftly asked it to 'show him someone he liked'. Holographic projections of Rose Tyler and then Martha Jones and lastly that of Donna Noble appeared, but he dismissed all these avatars, as they made him feel guilt. The interface proceeded to take the form of a young Amelia Pond. This version of the interface informed him that it was the poison of the Judas tree and then spurred him into action, with the phrase 'fish fingers and custard'. (TV: Let's Kill Hitler)
In 1974, when the Eleventh Doctor disappeared in a pocket universe, Clara Oswald tried to save him by travelling to him in the TARDIS. It was locked, and the TARDIS activated her voice interface in the form of Clara because the interface was programmed to "select the image of a person you esteem", which Clara took as an insult. After talking to Clara via the interface, the TARDIS unlocked herself and let Clara save the Doctor. (TV: Hide)
Other TARDISes
While he was in his "Roger", the voice interface of the Monk's TARDIS warned him that his misjudged attempt to correct the sound of the TARDIS hi-fi system by reducing the interior dimensions of the ship was ill-advised and that he should instead use a woofer. He refused to listen to it, but the interface would not budge; the Monk eventually gave up entirely and decided to listen to some LPs instead. (PROSE: How The Monk Got His Habit)
Whilst seeking pilots after achieving full sentience, the Master's wartime TARDIS communicated via an interface, which adopted the name "Mark". (AUDIO: The Broken Clock) It disappeared after Missy destroyed the ship by feeding it to the Master TARDIS's Eye of Harmony. (AUDIO: The Belly of the Beast)
Behind the scenes
- In Scream of the Shalka, a 2003 webcast not considered a valid source by this Wiki, the consciousness of the Master, inside an android body, has become integrated with the TARDIS, serving as an interface between the Ninth Doctor and his Ship's systems. In earlier drafts, the part of this Master was played by an entity even closer to the voice interface as eventually featured in Let's Kill Hitler, as it was supposed to be a projection of the Fifth Doctor.