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I would like to set the RTC time on sim868 manually. Trying to use the at-commands however I think my syntax is incorrect. The network I am using does not support providing the time hence the reason i want to manually enter the time.

AT+CCLK?
+CCLK: "04/01/01,00:00:37+00"
 OK
 AT+CCLK=19/09/17,09:56:00
  +CME ERROR: invalid characters in text string
  AT+CCLK=190917,095600
  +CME ERROR: invalid characters in text string
  AT+CLK="01/05/06,22:10:00"
 +CME ERROR: unknown
 AT+CLK=01/05/06,22:10:00
+CME ERROR: unknown
JOHNDOE
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2 Answers2

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You almost had it @JOHNDOE ... the timezone is needed at the end of the string. And I found it has to be two digits, not one.

This is actual serial terminal output from my SIM868:

AT+CCLK="19/09/17,09:56:00+00"
OK

See page 101 of SIM800 Series_AT Command Manual_V1.10

Vince K
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You need to get a better understanding of AT command parameter syntax (specifically strings) and you do that by reading chapter 5 in V.250 which is an extremely important document. (Reading tip: for your purpose ignore everything related to IA5 and just treat it as ASCII)

Then specifically for the command AT+CCLK (I do not think AT+CLK exists) you need to check its documentation. The very best thing is to get hold of the official AT command documentation from the manufacturer of the product you are using. You should spend a significant amount of effort in trying to get hold of this (including asking the manufacturer's customer support if necessary). Failing to do successfully do that, the second best thing is to use the 3GPP standard that specifies the command, which is 27.007. Searching for the string "CLK" I see that the AT+CSDF command affects the time format of AT+CCLK among other things.

hlovdal
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