Question on SYNC function

Discussion in 'General TomTom Discussion' started by fanchee, Jan 24, 2007.

  1. fanchee

    fanchee

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    Ok guys, I flew today from Dallas to Tucson and went from CST to MST - a one hour time difference. Maybe I am misunderstanding the sync function. I THOUGHT that once I turn the unit on, I go to the time page and just press sync. From there it would use satellites to determine my location and set correct time. This just didn't happen. Do I have to manually set the time and THEN press sync? If so, what is the purpose?
     
    fanchee, Jan 24, 2007
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  2. fanchee

    Pedro2NR

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    The sync button is one to ponder about. When I first used the sync button it was off by 30 minutes. When I used it a month later, it gave me the correct time.
     
    Pedro2NR, Jan 24, 2007
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  3. fanchee

    fanchee

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    When I went to sync, I didn't change the time first. I think changing the time first then clicking sync sort of defeats the purpose. Looks like, though, in order to get the correct time, I'll have to change the time EACH TIME I enter a new time zone. Ugh.
     
    fanchee, Jan 24, 2007
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  4. fanchee

    battom

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    That's ridiculous... a PND/GPS should know where you are... including timezones.


    ...And 'sync' automatically! I'll have to convert back to my old menu to get the option back (wonder if the menu maker author could make a 'which menu do you want to use' option..like the which map to use).

    however I don't travel much out of my timezone so real worl testing would be a bit difficult for me. Fanchee, you and I talk alot, maybe we can work out some testing offline and then post our results?

    ....unless anyone else has already figured this out! :D
     
    battom, Jan 24, 2007
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  5. fanchee

    fanchee

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    Sounds good to me. I'm in a different time zone pretty much every week and would love to get this sorted. I just can't believe I have to manually change the time each time, and THEN sync. Doesn't make sense.
     
    fanchee, Jan 24, 2007
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  6. fanchee

    battom

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    Did you by any chance try to contact TomTom Support about this?
     
    battom, Jan 24, 2007
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  7. fanchee

    fanchee

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    No, thought I would toss it out here first, since the responses are much more timely.
     
    fanchee, Jan 24, 2007
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  8. fanchee

    The Spook

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    Guys,

    Pressing 'sync' sets the clock to UTC (Universal Coordinated Time), based upon the GPS Time signal that is received from the GPS sats. GPS time and UTC time are not the same as UTC is adjusted to account for deviations in our planets orbit and it's slowing rotation, GPS time is fixed.

    A GPS receiver doesn't care what your local time is, as it only works using GPS time. It does know where you are, it just doesn't adjust the clock for you.

    So, press the 'sync' button to get UTC time set correctly, then adjust for your local timezone. Usually, you will only need to adjust the number of hours. Some people (E.g.: Australians) also have 1/2 hour deviations (GMT -9.5 for Oz I think).
     
    The Spook, Jan 25, 2007
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  9. fanchee

    khuon

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    I'm inclined to believe that the TomTom (being an embedded linux system) uses the standard linux PPS processing to adjust its system clock. In this model, several samples must be taken and then compared before an accurate set of parameters (time reference clock, drift, frequency offset, etc) are achieved. This can take several minutes. Additionally, some kernel implementation don't like large time leaps thus they will slowly skew themselves to the correct time. I suspect that the Sync button actually forces an instant set of the system clock to whatever value is keyed into the TomTom at the time and does not necessarily perform the function of synchronising to the GPS satelites' clocks. But again, this is all pure conjecture.
     
    khuon, Jan 25, 2007
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  10. fanchee

    The Spook

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    No, it doesn't. It is easy to test this. Set the clock to whatever crazy time you want, press sync and it will jump back to UTC time. The UTC time is based on the GPS time signal received from the sats (That's why it will only work when you have a signal).
     
    The Spook, Jan 25, 2007
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  11. fanchee

    Pedro2NR

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    Thanks for the explanation Spook.
     
    Pedro2NR, Jan 25, 2007
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  12. fanchee

    fanchee

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    Thanks, Spook. I was hoping for a different answer, but alas, it is what it is. Not that big of a deal to change the time on the unit every week. Just would have been more convenient had the unit auto-updated the time based on where I was located. :)
     
    fanchee, Jan 25, 2007
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  13. fanchee

    battom

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    Yeah, Thanks Spook. great answer... not the one we were hoping for, but you DID clarify!
     
    battom, Jan 25, 2007
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  14. fanchee

    The Spook

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    Glad I could help guys, sorry it wasn't what you where hoping for though...

    Maybe a future improvement that TT could implement? Here's hoping!
     
    The Spook, Jan 29, 2007
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  15. fanchee

    Nextourer

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    Nextourer, Feb 3, 2007
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  16. fanchee

    battom

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    Nextourer... am i missing something? the only thng I see about GPSFix from your link is
     
    battom, Feb 3, 2007
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  17. fanchee

    battom

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    Nevermind... I found it under
     
    battom, Feb 3, 2007
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  18. fanchee

    sweet sx

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    Sync

    Well this sync feature leaves a lot to be desire. I have a Garmin GPSMAP 76C and it will keep current time in what ever timezone I am in and then to beat another feature it will automatically change from day mode screen to night mode with out any user input. It goes of the local sunset sunrise data.

    I have a TT 1XL I like it but it is a step back in some ways for me.
     
    sweet sx, Dec 20, 2007
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