Final answer:
The correct term for software used for modems that connected through phone lines is terminal-emulation software. It enabled PCs to act like terminals to access remote systems. Bulletin Board Systems (BBS) were common uses for such software in the 1980s.
Step-by-step explanation:
The software used for modems that connected through phone lines was known as terminal-emulation software. This type of software allowed a personal computer to emulate a terminal, enabling users to log into remote systems such as a mainframe or minicomputer. An illustrative example from the 1980s is a Bulletin Board System (BBS), which users could dial into using their modems. BBSs featured colorful text and simple graphics to engage users, and though they were basic compared to modern websites, they were quite revolutionary at the time for communication and sharing information.