USB modem connecting to GSM network with SIM

[jgy2001]

I like to know if any of you have use USB modem adapter to connect GSM networking using adapter build in SIM socket?

We are using Asian 7" Android Tablets with WiFi only.

Is there Android software driver for these USB modem adapters?

 

[jgy2001]

Can any one with experiences with AT&T and T-Mobile GSM network using USB 3G dongle. tell me more about this USB adapters and Android app drivers and software?