Hello

I wanted to ask which DB9 serial port to USB converter cable I could buy on ebay/ali to connect to the external DB9 serial port (male!) connector of a Routerboard.

Most of the serial converters I find on ebay use a female connector too. But I assume a basic male-male adapter won't work because of the polarity of the different pins.

Which one do you have and work on your Routerboard?

Thank you

Routeboard connector is same as on PC (ie. routerboard appears as another "PC", not a device, so you can't connect them directly). So connector on RB is same (male) as on your typical usb to serial adapter (USB to db9 male). What you need is "null modem cable" with two female db9 connectors on both sides. This cable crosses the rx/tx pins so two PCs can talk to each other. You can buy one or make one yourself if you have any serial cables laying around.

Thank you for the information !