Send commands to the device via text message, why did not return information?

Possible factors caused by the following aspects:

1, the equipment without mobile phone signals or power is turned off, call on the device SIM card number, see if there is a normal through sound;

2, check card opened SMS function;

3, check whether text messages stored on the card, too much;

4, possible delay of SMS gateway;

Products: Asset GPS tracker; Car GPS Tracker; Scooter GPS tracker; Person/Pet GPS tracker

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