You can query the communication settings using the stty program like this: stty. Notice that once you run a program like minicom, the port is left with the settings that minicom used. If it weren't set up appropriately, the cat and echo commands would not do for you what you might have expected. Background The main reason why you need any program like minicom to communicate over a serial port is that the port needs to be set up prior to initiating a connection.
