Thank you alzhao.

Yes I am doing two USB to RS-232 (UART) devices with no issues.

I am also looking to expand play space (RAM). What would you recommend? A microSD would be ideal but I am already using the GPIO pins.

Would a USB to MicroSD card then be recommended?

Just noticed you are selling the GL M7620N board. I didn’t know you were selling it.

Today purchased a dual port microrouter using the 7620 CPU and getting ready to test a similiar device though with 128Mb of DDR RAM.