RS 422/ RS 485

I need 1x RS 232 and 1x RS 422/485 port – what is best way to get RS 422?
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armStoneA8 offers 3 serial interfaces (1x RS232 with RX,TX,RTS,CTS, 1xRS232 RX,TX and 1x TTL level RX,TX).
To get RS485, RS232 has to be converted to RS485 (because it needs a RTS control signal), or use the line driver for RX/TX TTL to get RS422.