[tz] Cellphone tz updates often not happening in Israel

Dennis Ferguson dennis.c.ferguson at gmail.com
Tue Sep 24 16:42:05 UTC 2013

On 23 Sep, 2013, at 16:32 , L. David Baron <dbaron at dbaron.org> wrote:

> On Monday 2013-09-23 13:07 -0700, Paul Eggert wrote:
>> end users in Israel.  Many cellphones running Android,
>> BlackBerry, iOS, and Symbian were still based on tz release

My previous phone was a Symbian phone.  I wouldn't update it
since that generally made it worse than it already was...

> It also seems odd that these phones didn't have their time adjusted
> as a result of receiving NITZ messages from cell towers with the
> correct UTC offset.  I thought that using time and timezone
> information from the cell network was the typical default
> configuration on smartphones (which makes having an up-to-date
> timezone database less critical).
> Are there carriers in Israel that don't broadcast date and offset
> information from their cell towers?  Or were the carriers
> broadcasting incorrect data?

GSM towers traditionally had no idea what time or timezone it is,
and many (maybe most) GSM and UMTS base stations still don't.  NITZ
isn't very common.  I think the "TZ" part of NITZ may have been
invented to solve a problem specific to American carriers, that
they were deploying GSM into a market where the competing digital
technologies (CDMA and IS-136 TDMA) could set the time and timezone
on the handset and didn't want their GSM service to not have that
feature too.  I've seen the "NI" part of NITZ, without the TZ part, in
use in China (despite what the Wikipedia page says) to identify the
"area" the tower you were connected to was in, since they used to
charge people different prices for calls in and out of their "home"
area.  In any case, outside of the Americas it is fairly rare to
find a carrier which provides this service, so smartphones seem to
often include plain old NTP and time zone files as a fall back while
dumb phones need their clocks set by hand.

Note that in the US mobile phone base stations always know what
time it is since they pretty much always have GPS receivers, for
E911 positioning if not for network time synchronization.  In
many other countries, however, it is considered a bad idea to
allow your telecommunications infrastructure to become dependent
on a service owned and operated by a foreign military so they
are less likely to do this.

Dennis Ferguson

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