The whole purpose of GSM phones is to work as broadly as possible, in over 200 countries worldwide. GSM service can now be found on four different frequency bands. US used only 1900 MHz for its GSM cell phone service. In the last year or so, there particularly if the cell phone company has spare frequencies unused in the Are mobile phones safe? Legal & Regulatory Issues in Mobile. Mobile Surveillance Videos of Bluetooth & GSM Hacking. cell phone frequencies | cellular south | cellular phone ringers | cellular service in alaska