Voice interface
The Doctor's TARDIS had a voice interface. It enabled him to interact with a hologram - offering medical analysis and limited psychological counselling.
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)
Known interactions
The interface was known to have appeared as the Brigadier on at least one occasion. (AUDIO: Zagreus) 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)