how to know the bands of my gsm cell phone

There are many gsm cell phone manufacturers in China, however, most of them are producing gsm cell phones based on MTK chipset.
If the cell phone is based on MTK chipset, then, you can know find the bands supported from a code.
It is *#3646633# .
press the keys list above , then, you can find the bands that the cell phone can work.
You can select the correct bands in your country.
You may also select auto , if so , the mobile phone can search the bands by itself.