RealTerm software is an open-source terminal program that can be used to communicate with serial ports and perform various tasks such as sending/receiving data, debugging, and logging. Its most important features include a simple and intuitive user interface, support for various data formats and protocols, and the ability to automate tasks using macros and scripts. Additionally, RealTerm allows users to view and analyze data in real-time, making it a useful tool for developers and engineers.