I've used either MiniCOM and GTKTerm so read data from serial ports before. These work well if you just want to read the raw serial data.
Most programming languages have a way to read from serial ports too. For example the PySerial module allows python to read from serial ports. You'd use a programming lanugage and it's serial port 'library code' to do more complex interactions with the serial port. For example displaying a graph of the data from the serial port rather than just seeing the text scroll on the screen.
Electronic and Computer Engineer
Pi Interests: Home Automation, IOT, Python and Tkinter