Hi R6,
If I understand your request you have a USB bluetooth device which when connected to a PC initiates as a serial interface using a FTDI driver.
You are now trying to do the same thing on Linux mint. If that is correct then you need the FDTI driver which should be included in linux mint (If not then correct driver can be downloaded from ftdichip dot com site).
When you plug the USB in it should create a device in /dev eg: /dev/ttyUSB0 (note the device will appear and disappear when you connect and disconnect the USB port).
If you want a two way connection then you need a terminal programme (as opposed to a terminal session) such as minicom or cutecom
If you just want to read the output then the following command will output the device data to the command line:
cat /dev/ttyUSB0
Note you may get garbage if the serial parameters do not match.
HTH
EG