Complex sentence: In 1970, the FCC made its first attempt at dividing the computer world into two categories: computers that ran communication networks and computers at the end of telephone lines that people interacted.
Split into simpler sentences: In 1970, the FCC made its first attempt at dividing the world. It decided that the appropriate division would be between those computers that ran the communications network and those computers at the ends of the telephone lines with which people interacted.