I've just started rewatching the new who and something occured to me about the timephone jiggery pokery the doctor does on Rose's phone to let her call her mum from 5 billion years in the future. What I'm wondering is does it recalibrate to her personal timeline or is it set? That is when she uses it she seems to call the next few hours that have passed for her and then due to the Doctor mucking up his steering she winds up missing a year. So what I'm wondering is if she then used her mobile would it call at that time because she was "missing" for 12 months or would she be calling last year as only a day or less has passed for her? For that matter is it transmit only as presumably at some point in the missing year her mother or Micky tried calling her and got an "out of service range" message.
I assume, as far as it isn't merely a plot device, it links through the TARDIS and resets based on the user's travels. So it links to the point in time she departed, offset based on her experienced time; if she left home at 00:01 on 01JAN2010 and phones home after she's experienced the passage of three days, it calls the number at 00:01 on 04JAN2010. Presumably the phone's time and date show this too. If she returns home to 12:00 on 01FEB2010, the phone resets to this, and if she leaves and travels for two weeks the phone will call 12:00 on 15FEB2010.
That's my take, based on the Whoniverse's general abhorrence of paradoxes.
Time, time,time, see what’s become of me. While I looked around for my possibilities... My AITAS files.
Consider the order of events. In Rose, the last contact Rose has with Jackie is a phone call just after the Autons stop attacking. Jackie is panicked, and Rose hangs up on her.
Then, in The End of the World, for her only a short while after the Auton incident, Rose calls her mother from five billion years in the future. Jackie answers perfectly calmly and acts as if it's no big deal that Rose has called her.
Later, in Aliens of London, Rose returns home and learns that a whole year has passed. People have been searching for her.
Jackie couldn't have gotten the superphone call from Rose after the Auton incident, because Jackie has been worried about Rose ever since. After Aliens of London, Rose calling or appearing is always an exciting thing for Jackie. Rose must have called Jackie sometime before the Auton attack in order to get the nonchalant response from Jackie.
Why would the phone call Jackie before the Auton attack? The Doctor probably got it wrong.
And, of course, the main reason: the superphone is just a plot device that they didn't care about making realistic. It's just there to keep Rose grounded.