(
National
Science
Foundation
NETwork) The network funded by the U.S. National Science Foundation, which linked five supercomputer sites across the country in the mid-1980s. Universities were also allowed to connect. In 1988, NSFnet was upgraded from its original 56 Kbps lines to T1 circuits. By the early 1990s, it was using a T3 line that served as the primary Internet backbone until 1995, when the Net became commercialized. See
ARPAnet and
Internet.