GSM Sim card question.

Hi.

I am from the U.S, and wanted to pre-setup/activate my phone with a GSM Sim card

for use in New York.

Bought a inexpensive I-Style 2.6 mobile phone from Central Department in Pattaya.

The dealer stated my Phone is unlocked.

I activated a GSM H2O nano sim card that works on T-Mobile & AT&T.

Aircard & Sim card number were setup/activated successfully online.

When I put the H2O sim card in the mobile sim slot, no screen response from my mobile.

It appears the sim card is not being detected.

Questions:

I am still in Thailand when I inserted the H2O sim card into my phone. Does that matter?

Do I have to be in the U.S to apply sim card?

Below are the GSM frequencies for this phone(see below).

Are they incompatible for North America?

Network 2G: GSM 900/1800 MHz.
3G: GSM 850/2100 MHz or 900/2100 MHz for the i-STYLE 2.6A.

• Technology for - send HSDPA 21 Mbps / HSUPA 5.76 Mbps.

• IPS display resolution of 480 x 800 pixels wide by 4 inches.

• Operating system, Android 4.3 Jelly Bean

• Processor Qualcomm Snapdragon MSM8610 1.2GHz Quad Core.

Thanks.

TC.