FT232RL(From England) : 
Industrial grade USB to RS232 Adapter
Industrial grade USB to RS485/RS422 Adapter
Industrial grade with RJ-45 interface USB to 485/422 Adapter

PL2303HX(From Taiwan):
Commercial grade USB to RS232
Commercial grade USB to RS485
Commercial grade USB to RS485/RS422

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FT232RL(英国方案）：
工业级USB转232
工业级USB转485/422
工业级RJ45接口USB转485/422

PL2303HX（台湾方案）：
商业级USB转232
商业级USB转485 
商业级USB转485/422 
