Bangkok Sim Card for data roaming

[inquisitor]

Originally Posted by kktk

From what I saw...AIS is the only one that offers the Pocket Wifi(which believe is the HUAWEI_E583X). It seems that it works at 7.2MB/s.

You don't necessarily need to buy the device from the operator which you intend to use. Just make sure it's unlocked and supports the required 3G frequency.

Also, I just saw something confusing on AIS's website...that their 900 frequency band for 3G is for CDMA? I thought it was all GSM??

What they run on 900 MHz is a UMTS network, which sometimes is also designated as "WCDMA", "HSPA" or "3G" and in the US such networks are even considered "4G" once they support very high speeds using HSPA technology.
GSM in contrast is the predecessor standard that is also called "2G". UMTS evolved from the GSM standard, that's why UMTS devices are always backwards compatible to GSM.

Both are incompatible with the American CDMA/EV-DO standard which is also called "3G".

2G, 3G and 4G are rather non-technical terms that describe the 2nd, 3rd and 4th generation of radio standards which are not necessarily compatible with each other.