Dear Wai Aung
The Bsmart b'AT (A500 and M500) cannot work with any network types. Bsmart b'AT can work only in the 2G technology (cannot work in 3G).
When you see the "G" in your phone, it means that the network is very slow.
You can see the speed for each type of network in the attached file.
According to attached file, G stands for GPRS and is the slowest standard, used is the GSM network (2G). E is an extension of GPRS, it is called EDGE and it is correspondingly a little faster, but still uses the old GSM network (2G).
You might try the following commands to reduce the data loss.
1) Set Log Position Interval = 60 (Reporting back to server every 60
seconds)
2) Set Log Position Distance = 200 (Reporting back to server every 200
meters)
3) Set POSITION REPORT NUM = 1 (Sending every single data back to the server. Now the default value is 3 that 3 datas will be packed together and send to the server)
4) Set SPECIAL EVENT ACK ENABLE = 4 (To ensure no missing report) (Please see attached file).
You will need to do the actual experiment on the highway with the commands above. These 4 commands will not help if there is no 2G signal in the highway.
Best Regards,
Vasin