/sys$common/syshlp/helplib.hlb SET, TERMINAL, Qualifiers, /HANGUP  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /HANGUP
       /NOHANGUP (default)

    May require LOG_IO (logical I/O) or PHY_IO (physical I/O)
    privilege depending on system generation parameter settings.

    Controls whether the terminal modem is hung up when you log out.