iSH

Hercules SETUP utility is a useful serial port terminal (RS-485 or RS-232), UDP/IP terminal and TCP/IP Client Server terminal. It was created for HW group internal use only, but today its includes many functions in one utility and its Freeware!

CuteCom is a graphical serial terminal aimed mainly at hardware developers or other people who need a terminal to talk to their devices.

kdialog allows you to display dialog boxes from shell scripts. The syntax is very much inspired from the "dialog" command (which shows text mode dialogs).