VMS Help TCPIP Services, TELNET, TN3270 Keyboard Functions, SHO_MSG  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    VT100: EXT + G              VT200: EXT + F14
    DEFINE_KEY Function: SHOW_MESSAGE

    Displays the broadcast messages that have been posted on a
    separate screen. If the status line is enabled, Msg appears on
    the status line. If you do not read the messages before they fill
    up the screen, the messages begin to scroll up out of view and
    you will no longer be able to read them. These broadcast messages
    are not saved after you read them or exit TN3270.