Only ttymxc0 and ttymxc1 are checked in the list, is this normal?

[peterkwon 1]

My tinker edge t board has two UARTs, ttymxc0 and ttymcx1.
If you don't see ttymxc2 in the get start documentation, it says to do sudo apt-get dist-upgrade. However, ttymxc2 is not visible even after rebooting after sudo apt-get dist-upgrade.
When ttymxc0 and ttymxc1 are opened for UART communication, communication is not possible, so I want to know what to do to enable uart communication.

Regards

[ulorenz 0]

sudo nano /boot/config.txt

#intf:uart3=off --> inft:uart3=on