AT&T announced UNIX System III based on Version 7, and PWB in 1981. Licensees could sell binary sublicenses for as little as , which observers believed indicated that AT&T now viewed Unix as a commercial product. This also included support for the VAX. AT&T continued to issue licenses for older Unix versions. To end the confusion between all its differing internal versions, AT&T combined them into UNIX System V Release 1. This introduced a few features such as the vi editor and curses from the Berkeley Software Distribution of Unix developed at the University of California, Berkeley Computer Systems Research Group. This also included support for the Western Electric 3B series computers. AT&T provided support for System III and System V through the Unix Support Group (USG), and these systems were sometimes referred to as USG Unix.