This example is for Trendnet USB to serial adapter v2
After install del driver for your Mac and restart the Mac.
Open a terminal session and type.
#ls /dev/tty.*
note the list of the usb-serial com port per example
/dev/tty.usbserial (in my case)
Then use screen commandon the terminal in order to access your serial appliance, per example
#screen /dev/tty.usbserial {baudrate}
After install del driver for your Mac and restart the Mac.
Open a terminal session and type.
#ls /dev/tty.*
note the list of the usb-serial com port per example
/dev/tty.usbserial (in my case)
Then use screen commandon the terminal in order to access your serial appliance, per example
#screen /dev/tty.usbserial {baudrate}