[time-nuts] Smart Phone time display accuracy...?

Attila Kinali attila at kinali.ch
Mon Mar 27 15:45:46 UTC 2017


On Sun, 26 Mar 2017 16:29:10 +0100
shouldbe q931 <shouldbeq931 at gmail.com> wrote:

> Not all phone networks provide time, I was quite surprised in the 90s
> when I crossed the English channel going to France and the time on my
> (GSM) phone automatically updated, and just as disappointed when I
> returned and the clock did not update, this was of course long before
> "smartphones" with GPS or NTP clients...

Ok.. to get this back on a bit more time-nutty things:

Modern cell phone protocols either require or contain provisions
to diseminate local (and UTC) time to the cellphones. This is also
being used as a timing standard for situations where LF stations (WWVB/DCF/..)
are not good enough, but no GPS antenna can be used for whatever reason.
I most civilized countries this timing code will be quite accurate,
down to the µs level. But there are a lot countries where you cannot
expect the time code to be anywhere close to reality. E.g. Networks
in India are known for transmitting time codes that are multiple minutes
off and nobody cares about correcting that.


			Attila Kinali


-- 
It is upon moral qualities that a society is ultimately founded. All 
the prosperity and technological sophistication in the world is of no 
use without that foundation.
                 -- Miss Matheson, The Diamond Age, Neil Stephenson



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