Time Changes on the Atlantic Ocean

Discussion in 'iPhone' started by warburg, Jul 29, 2009.

  1. warburg macrumors 6502a

    Jul 27, 2008
    I am sailing for Hamburg on the Queen Mary II tomorrow. The voyage takes eight days, and on six of these days the ship's clocks are set an hour ahead at 2:00 AM. If I have data roaming on, will there be automatic time changes on the iphone during the voyage? Can time changes be made manually?
  2. FXT 1 macrumors 6502

    Jul 14, 2009
    I doubt it, plus you'll pick up expensive roaming charges. Just turn roaming and push etc. off and set international times in your Clock App->World Clock, as messing about with your local time prompts a change to world times on the iPhone.
  3. goosnarrggh macrumors 68000

    May 16, 2006
    Timezone updates over GSM is implemented using an optional feature of GSM called NITZ. Carriers who choose to support it may send these messages automatically at their convenience, but they typically send them every time a phone logs in to the network, and every time a daylight savings time change takes effect, or every time a phone crosses out of one timezone and into another. That is to say, if your phone is establishing a connection with a cell tower owned by a carrier who supports NITZ, then every time you turn off-and-on any GSM phone (regardless of whether it supports NITZ or not), you will end up receiving a NITZ update. Your phone may not know what do do with it, or it may be configured to ignore it, but the message is delivered whether you want it to or not.

    These messages, if supported by the carrier, are delivered to the phone using much the same channel of communication as an incoming SMS message. I don't think turning off international data roaming has any effect on blocking incoming SMS messages, because SMS messages don't use the same channel of communication as other forms of data. So I don't suppose disabling international data roaming would have any effect on incoming NITZ messages either.

    That being said, many GSM carriers have chosen not to implement NITZ.
  4. warburg thread starter macrumors 6502a

    Jul 27, 2008
    I'll bet this is fascinating, but I'm a 78-yar-old retired English teacher, and I don't understand Computerize. Are you saying I should just leave the damn thing alone, and it will adjust itself :confused::D

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