Alinco: Diferences between Alinco DR-638HE and DR-638T

[KP4RO]

I plan to buy a new dual band radio for my car and because I wanted a radio that I can set a search scan range between two frequencies in VFO or two memory channels on the Alinco DR-735T, DR-638 and DR-638T by setting "L" for stand lower scan set and "U" for upper scan set. Because these three Alinco radios do that I want to know the differences between them.