In general most wireless phone carriers use one of GSM 900, GSM 1800 or 3G Technologies. These refer to the different frequencies the carriers use to broadcast their network signal. Some carriers use to broadcast their network signals. Some carriers are licensed to use both GSM 900 and GSM 1800, which means that you will need a dual band mobile signal booster GSM 900/2100 Mobile signal booster and GSM 900/ 1800 mobile signal booster in order to ensure compatibility.