What is the purpose of 'set time zone' for DST?

viewfly

macrumors 65816
Original poster
May 1, 2009
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I asked this last fall. I have 'set time zone' off because of battery issues I had last fall with 5.0.1 and I still have it off with 5.1 just to be safe.

Why? Because what does it do?

My Fall Forward DST correction worked fine this AM. The time setting comes from the towers like it always does.

So what is the purpose of this
Switch???
 

viewfly

macrumors 65816
Original poster
May 1, 2009
1,264
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Not all time zones changed time this morning. I'm in the UK and we don't change for another two weeks.
So? It still is set by the carriers tower as it was done by non smartphones.

The GPS in LBS is not needed.
 

Gav2k

macrumors G3
Jul 24, 2009
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What it does is continually check your location and update the time as you travel so if you where driving across America it would change at every time zone.

The dst is set by network
 

viewfly

macrumors 65816
Original poster
May 1, 2009
1,264
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Wirelessly posted (iPhone 4s: Mozilla/5.0 (iPhone; CPU iPhone OS 5_1 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Version/5.1 Mobile/9B179 Safari/7534.48.3)

What it does is continually check your location and update the time as you travel so if you where driving across America it would change at every time zone.

The dst is set by network
No I don't thing so. The towers have GPS clocks in them and the local time. This sets your phone clock the way it always has...for the last 15 yrs of my phone use.

This is why the time is set correctly in old non smartphones without gps.

Always worked fine in my old nokias from NYC to calif. to Paris.
 

viewfly

macrumors 65816
Original poster
May 1, 2009
1,264
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For iPhones yes, but for those who has their data disabled or an iPod Touch, iOS has those settings in place.
For iPod touch I can understand. But the timing is important for Cellular use and comes from the tower network. Just like how your landline has the correct time and sets the clock on your land phone or answering machine.
 

viewfly

macrumors 65816
Original poster
May 1, 2009
1,264
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I have been on SINET/Cingular/AT&T since 1995. My cell phone clock has always been set by the network as I travelled from east to west coast and north and south. That was TDMA networks and now GSM.

And with GSM internationally the time is set when I landed... Before gps in phones.

Found this in the iPhone manual. Perhaps there are some carriers that don't do this...but for AT&T I don't see the need to use the LBS time switch.

Same with most international networks. Maybe some smaller networks don't. But I think the majors all do.
 

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Gav2k

macrumors G3
Jul 24, 2009
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viewfly said:
Wirelessly posted (iPhone 4s: Mozilla/5.0 (iPhone; CPU iPhone OS 5_1 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Version/5.1 Mobile/9B179 Safari/7534.48.3)

What it does is continually check your location and update the time as you travel so if you where driving across America it would change at every time zone.

The dst is set by network
No I don't thing so. The towers have GPS clocks in them and the local time. This sets your phone clock the way it always has...for the last 15 yrs of my phone use.

This is why the time is set correctly in old non smartphones without gps.

Always worked fine in my old nokias from NYC to calif. to Paris.
There are times were a cell signal isn't available!
 

viewfly

macrumors 65816
Original poster
May 1, 2009
1,264
22
Wirelessly posted (iPhone 4s: Mozilla/5.0 (iPhone; CPU iPhone OS 5_1 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Version/5.1 Mobile/9B179 Safari/7534.48.3)



There are times were a cell signal isn't available!
Ha! Then I would absolutely turn this time switch off! Finding the time zone via GPS without a cell signal to speed things up would be a double battery drain.

Use a watch.