KT-4077 is the US export model of KT-GS5, KT-V770 the EU model. It came in black only, while KT-GS5 came in white, black and red.
KT-AS2 succeeds KT-AS1: KT-AS2 has only one headphone jack and the tuner cards are different. ≡
Unlike KT-VS1 and KT-VS2, the AM/FM tuner is now built-in. This is last model in the RT-VS series, non auto-reverse. The RS-V300 is the portrait mode version.