[BC66] How to deal with Time zone and Daylight Saving Time (DST)?

IoT Modules LPWA Module
1

Hello all,

What I’d like to do is for a BC66 to know what the local time is, without having to tell the BC66 which country it is in or whether the local area is currently experiencing DST or not.

Currently I’m in the UK, and the time zone is British Summer Time. Which equals GMT + 1 hour.
The local time now is 10:28. GMT time at the moment of writing would be 09:28.

What I’d like is for the BC66 to discover the local time for itself, based on the network time. When I use the QCCLK / CCLK commands, I get the wrong results however.

+QCCLK: 22/03/31,09:28:42+08 
 OK
AT+CCLK?
 +CCLK: 2022/03/31,09:28:42GMT+2 
 OK

What i would be expecting is to get 09:28 GMT +1, not GMT +2. Because 09:28 GMT + 2 would equal 11:28 and that is plain wrong.

Does anyone know how I could get the actual and correct local time?

Any help is much appreciated!

2

I presume you do have NITZ enabled on the modem, with AT+CTZU=1

I’m in Australia, and the instances I’ve seen of the offset from GMT being wrong have always been the fault of the network broadcasting the NITZ information.

You should consider that as a possibility until proven otherwise.

A hard reset or power-cycle on the modem will force it to reacquire the GMT offset from the network.

3

hi,brixton:
I suggest you use NTP to synchronize your time to try again!

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4

I have a follow-up question regarding the use of AT+QNTP.

Where does the modem get its timezone information from if not from NITZ?

NTP does not provide this, all NTP times are in GMT/UTC.