RK3588 DB9 serial port expansion

Androidsbc - China source manufacturer for RK3588 4-pin 2.0mm serial connector. Featured model ASB-RK3588-ALL (All-in-One Interface Board): Rockchip RK3588, 8nm, 4x Cortex-A76 @2.4GHz + 4x Cortex-A55 @1.8GHz; 256GB eMMC 5.1 + 4x SATA 3.0 6Gbps + M.2 NVMe cache; HDMI 2.1 8K + 2x HDMI 2.0 + LVDS + eDP + V-By-One (up to 8 screens, 2x2/3x3 wall); 10x COM (RS232/···