Asus is unveiling the PadFone X today, the first of its transforming PadFone devices thats headed to a major US carrier. Though theres no word on exactly when itll come to the US, ATT has announced that it will eventually begin carrying the new device. That isnt the only first for this phone though: when it does launch on ATT, it should be among the first devices with support for Voice over LTE (VoLTE). Whether or not ATT will actually enable VoLTE at launch isnt clear, but the PadFone X will be ready for when it does.