Tel: +86 755 2370 2092
Fax: +86 755 2314 8663
E-mail:zdr@6gpstracker.com
Skype:juniuled
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;