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

       /SECURE_SERVER
       /NOSECURE_SERVER (default)

    Requires either LOG_IO (logical I/O) or PHY_IO (physical I/O)
    privilege.

    Controls whether the Break key on the terminal logs out the
    current process (except on a virtual terminal). With the /SECURE_
    SERVER qualifier in effect, pressing the Break key when there
    is no current process initiates the login sequence. With the
    /NOSECURE_SERVER qualifier in effect, the break is ignored.

    On terminals with the AUTOBAUD and SECURE_SERVER characteristics,
    pressing the Break key disconnects the current process, but
    is not required to start a new login sequence. However,
    when the NOAUTOBAUD characteristic is set, the SECURE_SERVER
    characteristic requires a break to initiate a new login sequence.