RS232 intergration with the TX2 development board kit

What are my options for connecting a RS232 device to the Jetson TX2 development board kit? So far I looked at J21 GPIO and J17 UART. Both are 3.3 or 5V and RS232 requires 12V. Would I need to use a RS232 to TTL Serial Converter? OR, can I use a USB RS232 adapter like I did when I prototyped my solution on a PC?

please see-also How do The UART port in TX2 convert to RS232??? - #8 by linuxdev, thanks