Since I had to Google it, 3Com was the company behind Ethernet, a wired networking standard that revolutionized offices in the days before remote work. Like with GUIs, the work started at Xerox PARC.
Since I had to google it, Metcalfe was one of the inventors of Ethernet.
Fun fact, he predicted in 1995 that the internet would collapse entirely within the following year, and said he would eat his words if it didn't. In 1997, at a web conference, he put a printed copy of the words into a blender and drank a smoothie made with that paper.