Superphone

The "Superphone" is an upgraded mobile phone that can make calls across time and space. It even calibrates to the user's home time period, as shown by Adam Mitchell's ability to call his home time on Rose Tyler's phone ("The Long Game"), despite their native time periods being about a decade apart. In addition, it can send signals in places ordinary phones cannot, such as the sealed Cabinet Rooms at 10 Downing Street ("World War Three"). It does not seem to work when the TARDIS is out of range ("The Impossible Planet"). The superphone first appears in "The End of the World", where the Ninth Doctor modifies Rose's Nokia 3200 mobile phone with a special device that goes in place of the battery. In "Rise of the Cybermen", the Nokia 3200 is replaced by a Samsung D500, but otherwise seems to function the same. It is also able to link up with the Cybus Industries Ear-Pod network. Rose gives the phone to Mickey Smith at the end of "The Age of Steel", but replaces it soon after. In the Runaway Bride,The Doctor borrows a person's phone at Donna Noble's wedding reception party.Using his sonic screwdriver he enables the phone to browse the internet at a super speed allowing him to find what he is looking for. After Martha Jones becomes an ongoing companion to the Tenth Doctor in "42", he gives her phone a similar upgrade. This phone, however, is upgraded by the Doctor's sonic screwdriver, and the feature itself is referred to as "Universal Roaming". Martha's phone has the Archangel network logo on its display, the significance of which is revealed in "The Sound of Drums". At the end of the episode "Last of the Time Lords", Martha gives her phone to the Doctor, so she can contact him if trouble occurs. He keeps the superphone and is later called by Martha during the Sontaaran invasion of Earth. He also upgrades Donna's phone and later Martha's superphone is used to track down the Earth when all of his companions call him on it, giving him a signal to follow.