Microcom Systems was a major moem vendor during the 1980s, although they were never as popular as the "big three", Hayes, U.S. Robotics (USR) and Telebit. Nevertheless they hold an important place in modem history due to their introduction of the MNP error-correction and compression protocols, which were widely used under license by most modem manufacturers in the 1990s. Compaq purchased the company in 1997.