M.2 M+B Key to 4x RS232 Serial Adapter Card — 4-Port M.2 Expansion with WCH384 Controller

Compact M.2 M+B Key adapter that adds four RS232 serial ports from a single M.2 slot. This 4-port serial expansion card functions as an M.2 to RS232 controller card and is driven by the WCH384 chip for reliable multiport serial communication. Use it to expand legacy RS232 connectivity via an M.2 M+B key interface — a practical multiport serial card and port expansion solution.