April 24, 2014 - 12:18am, 5451 views
I can imagine 3 ways to read current time using BGS2-T:
1. It is possible to read current time with at^sind command reading NITZ information, but remember that this feature is network dependent, so some networks won't support it. According to AT Spec the network usually sends a NITZ indicator when the mobile attaches to the network, when it enters a location area with different time zone or when a daylight change occurs.
There are two ways to read NITZ data:
A) Setup an +CIEV URC on NITZ update using commands AT^SIND="nitz",1 and enable URCs displaying with AT+CMER=3,,,2
B) Look up NITZ data with AT^SIND="nitz",2. Please be aware, that this data may be out of date as it is only updated in cases described above.
To get additional information on NITZ please refer to "nitz" description of AT^SIND command in AT Spec.
2. As above solution is network dependent you can check local time and timezone by reading an sms sent to the module (the module can send an SMS to itself). See following example:
+CMGR: "REC UNREAD","+xxxxxxxxxxx",,"14/04/07,13:00:12+04"
3. You could use Socket Internet Service to query NTP server over GPRS to obtain current time.
Hope you find my guidelines helpful.
I saw a notice in internet that in some operator cases you get the NITZ data when you attach to the GPRS.
Here is what I tried:
at+cgdcont=1,"IP","m2m.dna.fi" - I had a Finnish DNA m2m SIM card
All these times were righ compared with a reference clock.
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Nice tip! However, remember that this functionality is operator specific and can't be treated as 100% clock synchronization method.
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