Some phones support the 1700/2100 frequency band 4 on lte technology but say they don't have support for the 1700/2100 umts technology. They are the same band and frequency right so why don't they say they can work on umts and lte for the 1700/2100 band? Are the signals for those bands separate from the technology, gsm umts or lte? This is mainly for Verizon phones. Also for phones that have different variants of frequency support are they different in hardware or on a software/firmware level?