TARDIS telephone

A telephone capable of calling and receiving calls from anywhere in time and space was present in both of the Eleventh Doctor's TARDIS console rooms, as well as within the police box plasmic shell. His phone number was 07700 900461. (TV: The Stolen Earth, The Day of the Doctor)

When Jamie used Om-Com to call the police box phone, the Ninth Doctor said it wasn't possible — that phone was just a dummy. (TV: The Empty Child) The external phone was impossibly called again in the Doctor's eleventh incarnation, by Clara Oswald, having been given the number by a "woman in the shop". (TV: The Bells of Saint John) Clara continued to call this phone into the Doctor's twelfth incarnation. (TV: The Time of the Doctor, Time Heist)

The Ninth Doctor's TARDIS console had a phone; Rose Tyler was surprised to find it had one when the Doctor called her with it. "You think I can travel through space and time and I haven't got a phone?" It showed up on her call display as "Tardis". (TV: World War Three)

Nevertheless, the Tenth Doctor never used it, and instead made use of the mobile Martha Jones gave him for all incoming and outgoing calls. (TV: The Sontaran Stratagem/The Poison Sky, The Stolen Earth)

Following that console room's destruction and the TARDIS' "regeneration" into a new one, (TV: The Eleventh Hour) though, the Eleventh Doctor's TARDIS had one on the control console. Amy Pond was surprised to find it when Winston Churchill called; the Doctor replied, "It's a phone box." (TV: The Beast Below) In a psychic pollen-induced shared dream, Rory Williams suggested calling for help using the TARDIS phone as they approached a cold star. (TV: Amy's Choice)

Just after Rory and Amy's wedding, the Doctor was informed by phone about an Egyptian goddess loose on the Orient Express, in space. (TV: The Big Bang) It was also through this telephone that the Doctor was informed of the Brigadier's death. (TV: The Wedding of River Song) This console phone had a cord long enough that its user could use it outside. (TV: Day of the Moon, WC: Pond Life) It also had an answering machine. (WC: Let's Kill Hitler Prequel, The Doctor, the Widow and the Wardrobe Prequel)

The Doctor's next TARDIS also had a phone, and Vastra called it to tell him Clara Oswald satisfied the "one-word test" with the "pond". (TV: The Snowmen) The interior phone was rarely used, though, as, after Clara impossibly called him on the exterior police box phone, (TV: The Bells of Saint John) calls were directed to that phone instead. (TV: The Time of the Doctor, Time Heist) To call Kate Stewart, he was forced to hang outside of the TARDIS to reach it, as the TARDIS was in the air being transported by helicopter. (TV: The Day of the Doctor) Similarly, when Clara called him while he was orbiting Trenzalore with enemy ships surrounding him, he had to quickly reach out to get the phone. He gave Handles the command to remind him to patch the telephone back through the console unit to finally fix the problem, and this reminder ended up being Handles' final words before malfunctioning and "dying". (TV: The Time of the Doctor)

After destroying the Daleks and ending the Siege of Trenzalore, the Doctor retreated to the TARDIS before completing his regeneration and used the TARDIS phone to contact Clara from his future already travelling with his next incarnation to reassure her that he was still the Doctor despite having changed his appearance. He neglected to hang the phone back up afterwards. The Clara from his present came across the TARDIS and hung it up for him. She remembered doing this when she received the Eleventh Doctor's call while in the company of the Twelfth Doctor, allowing her to piece together the puzzle and accept that what the Doctor was telling her was true. (TV: The Time of the Doctor, Deep Breath)

Despite Handles' reminder to fix it, the Twelfth Doctor continued to use the exterior phone. He gave Karabraxos his phone number, which she used to call him in the past and set him and Clara on their heist in the Bank of Karabraxos. (TV: Time Heist) Clara also called this phone when she contacted the Doctor after the death of Danny Pink (TV: Dark Water). Clara's call display by this point identified calls to and from the phone as being from "The Doctor", though this wasn't the case when the Eleventh Doctor phoned her prior to his regeneration as she was unable to tell who was calling until she answered. (TV: Deep Breath)

PS : This is very confusing.