Vietnam's viettel has the most stable mobile signal, but not speaking Vietnamese can be difficult. Tools/materials, viettelsim card
Send DK to +191,
Got the 2G business package code,
Select the appropriate package and reply the package code to +191, such as sending D25 to +191 (25K package 30M package),
After successful commissioning, receive the configuration SMS message.
Save to configuration. The optional network connection should have the following: Viettel GPRS, VIETTEL WAP, VIETTEL MMS, 3G (WCDMA network),
If 2G is on, send OFF to +161,
Not ON over the network - send 3G ON to +161,
Send model D to +191 (e.g. "DN5800" to +191),
Get the configuration file and save it to configuration.
Send DK 3G to +191 to get the package code (e.g. MIXX),
Reply the package code (such as MIXX) to +191 to open (because I can only receive 3G data every day, every week, every month),
The optional network connection should have the following: VIETTEL_STREAMING (this connection point is both 3G), VIETTEL MMS.
Carefully identify the Vietnamese language to send the request, otherwise open the unnecessary function;
Use google Translate to translate Vietnamese into Chinese.