Network Identity and Time Zone (NITZ)
is a mechanism for provisioning local
time
Time is the continued sequence of existence and events that occurs in an apparently irreversible succession from the past, through the present, into the future. It is a component quantity of various measurements used to sequence events, ...
and date,
time zone
A time zone is an area which observes a uniform standard time for legal, commercial and social purposes. Time zones tend to follow the boundaries between countries and their subdivisions instead of strictly following longitude, because it ...
and
daylight saving time
Daylight saving time (DST), also referred to as daylight savings time or simply daylight time (United States, Canada, and Australia), and summer time (United Kingdom, European Union, and others), is the practice of advancing clocks (typicall ...
(DST) offset, as well as
network provider identity information, to
mobile devices
A mobile device (or handheld computer) is a computer small enough to hold and operate in the hand. Mobile devices typically have a flat LCD or OLED screen, a touchscreen interface, and digital or physical buttons. They may also have a physical ...
via a wireless network.
History
NITZ has been an optional part of the official
GSM
The Global System for Mobile Communications (GSM) is a standard developed by the European Telecommunications Standards Institute (ETSI) to describe the protocols for second-generation ( 2G) digital cellular networks used by mobile devices such ...
standard since phase 2+ release 96.
NITZ is often used to automatically update the system clock of mobile phones.
In terms of standards and other timing or network access protocols such as
NTP or
CDMA2000, the quality and enforcement of NITZ is weak. This standard allows the network to "transfer its current identity, universal time, DST and LTZ"
but each is optional, and support across
RAN
Ran, RaN and ran may refer to:
Arts and entertainment
* ''Ran'' (film), a 1985 film directed by Akira Kurosawa
* "Ran" (song), a 2013 Japanese song by Luna Sea
* '' Ran Online'', a 2004 MMORPG (massively multiplayer online role playing game)
* ...
vendor and operator varies. This presents a problem for device manufacturers, who are required to maintain a complex time zone database, rather than rely on the network operator. Additionally, unlike
3GPP2
The 3rd Generation Partnership Project 2 (3GPP2) is a collaboration between telecommunications associations to make a globally applicable third generation ( 3G) mobile phone system specification within the scope of the ITU's IMT-2000 project. In ...
, which transmits
GPS
The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite sy ...
-sourced, millisecond resolution time via the sync channel, for NITZ, the "accuracy of the time information is in the order of minutes".
The optional nature of the delivery mechanism results in issues for users in regions that don't practice daylight saving but which share a time zone with a region that does.
Most modern handsets have their own internal time zone software and will automatically perform a daylight saving advance.
Because the NITZ delivery is not usually periodic but dependent on the handset crossing radio network boundaries, these handsets can be displaying incorrect time for many hours or even days before a NITZ update arrives and corrects them.
Carriers supporting NITZ
Initial list derived from ref:
{, class="wikitable sortable"
, -
! scope="col" , Country
! scope="col" , Carrier
! scope="col" , NITZ available since
! scope="col" class="unsortable" , Notes
, -
, , , Optus , , Y , ,
, -
, , , Telstra , , Y , ,
, -
, , , Three , , Y , ,
, -
, , , Nar , , 2014 , ,
, -
, , , Rogers , , Y , ,
, -
, , , SaskTel , , Y , ,
, -
, , , China Mobile , , Y , ,
, -
, Croatia
, A1
, Y
,
, -
, , , Telefónica O2 , , Y , ,
, -
, , , T-Mobile , , Y , ,
, -
, , , Vodafone , , Y , ,
, -
, , , Bouygues Telecom , , Y , ,
, -
, , , Free , , Y , ,
, -
, , , Orange , , Y , ,
, -
, , , SFR , , , ,
, -
, , , DNA , , Y , ,
, -
, , , Sonera , , Y (pre-2000) , ,
, -
, , , Telefónica O2 , , 2009 , , ref
, -
, , , PCCW , , Y , ,
, -
, , , SmarTone , , Y , ,
, -
, , , T-Mobile , , Y , ,
, -
, , , Wind , , Y , ,
, -
, , , U Mobile , , Y , ,
, -
, , , Telcel , , Y , ,
, -
, , , KPN , , Y , ,
, -
, , , Vodafone , , Y , ,
, -
, , , 2degrees , , Y , ,
, -
, , , Spark New Zealand , , Y , ,
, -
, , , Vodafone , , Y , ,
, -
, , , MTN , , Y , ,
, -
, , , T-Mobile , , Y , , 2G and 3G
, -
, , , P4 Play , , Y , , 3G only
, -
, , , Plus (telecommunications Poland) , , Y , , 2G and 3G
, -
, , , Aero2 , , Y , , 2G and 3G
, -
, , , Zapp , , Y , ,
, -
, , , Salt , , Y , , 3G only
, -
, , , MTS , , Y , ,
, -
, , , Telia , , Y , ,
, -
, , , Telenor , , Y , ,
, -
, , , Sunrise , , Y , ,
, -
, , , Swisscom , , Y , ,
, -
, , , Salt , , Y , ,
, -
, , , Turkcell , , Y , ,
, -
, , , Vodafone , , Y , ,
, -
, , , Chunghwa Telecom , , Y , ,
, -
, , , Telefónica O2 , , Y , ,
, -
, , , Vodafone , , Y , , ref
, -
, , , AT&T , , Y , ,
, -
, , , T-Mobile , , Y , ,
, -
, , ,
, , - , ,
, -
, , , Türk Telekom , , - , , ref
References
GSM standard