How do I install US drivers on OSX?
This guide will show you how to install the FTDI drivers which work for US on OSX:
Download the drivers from the FTDI website: http://www.ftdichip.com/Drivers/VCP.htm
You will now need to delete the preinstalled Apple FTDI drivers:
On El Capitan you will need to use this command to see the device: screen /dev/tty.usbserial-xxxxxxxx [baud]