How to work with USB-Serial in OSx
WCH341 based hardware
Unfortunately, no tty device presented, only userspace hardware. You can download application from here
PL2303 based hardware
Firstly download a kext from link and put to the /System/Library/Extensions Then load kext and rebuild cache
cd /System/Library/Extensions
kextload ./osx-pl2303.kext
kextcache -system-cache
Then you can use your adapter from CLI
sudo cu -l /dev/tty.PL2303-000012FD