In the field of computer science, a smart terminal can mean a variety of things. In the early days of personal computers, the term "smart terminal" was used to designate auxiliary components that were compatible with a mainframe system. Since then, smart terminals have been able to do a variety of tasks, including enabling thin client capability compatible with an external server configuration. For instance, if a corporation designed a terminal to fit over a programmable logic controller or other control plane hardware component, and that component aided in communications, configuration, calibration, or any other function, the terminal could be deemed a smart terminal. Other intelligent terminals aid retail payment processing hardware configurations.