Below are the possible main reasons of device offline, we also provide checking way accordingly.
Some drivers like to turn off the battery of vehicle during parking, or the power wire connection between tracker and vehicle's power is disconnected (including be cut off by someone)
Checking the latest online data like external power and internal battery value before offline will get clear answer to this question.
2. SIM card without available credit
It is very common and is the main reason of device offline.
However, the common mistake is that the users think the SIM card has enough credit but actually the credit has run out.
- The device can reply SMS command doesn't mean the credit is enough: Device online needs the GPRS data plan. Part operators provide different packages to their customers. For example, calling and SMS are one package, the GPRS data is another package. It is logical that the device can reply SMS or the calling is normal but the GPRS data has run out.
- If the users use the M2M SIM card management platform, the situation is more complicated. The user can limit the data consumption of the SIM card. There are active/inactive SIM card, prepaid or postpaid options. Even everything looks normal, the M2M SIM card itself may have issues, especially under roaming network.
The challenge is that the GPS tracker supplier doesn't have a reliable way to judge the SIM card credit. So the users need to keep a good record of SIM card recharging. Two further steps are suggested below:
- Try to recharge SIM card if can't find other reasons of device offline
- Replacing with another proved SIM card for comparison testing
- Some types SIM card need registration. However, the challenge is that these SIM cards still can work for a period time (Eg: for around a month) even without registration. From the user's view, this device works well then suddenly offline, and can't work after the credit is recharged. They forget this SIM card need be registered.
Do the comparison testing with another proved SIM card always is the No. 1 suggestion for removing the dobut of SIM card.
- SIM card can't fit the SIM card slot well.In some countries, the SIM card's quality is not very good, or the vehicle's temperature is too high which affects the shape or touch pin of the SIM card. Finally the SIM card can't fit the SIM card slot well. The user can find that the SIM card from A operator is not working, from B operator is working. Or two SIM cards both are from the same operator but one works, the other one is failed.
3. Parameters are wrong
IP, port, APN, and the time interval are core parameters affecting the online.
We developed SMS command below to retrieve current parameters.
000000,C06 (000000 is default SMS command password)