VMS Help SET, TERMINAL, Qualifiers, /DISCONNECT  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /DISCONNECT
       /NODISCONNECT (default)

    Controls whether the process connected to this terminal is
    disconnected if the line detects a hangup. The /DISCONNECT
    qualifier is valid only when the /PERMANENT qualifier is
    specified.