VMS Help SET, BROADCAST, Parameter  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 class-name[,...]

    Specifies the class of message that you want to enable or disable
    for broadcast to your terminal. If you specify only one class,
    you can omit the parentheses. The class names are as follows:

    ALL                  Enables all message classes.

    [NO]DCL              Specifies Ctrl/T and SPAWN/NOTIFY messages.

    [NO]GENERAL          Specifies all normal REPLY messages or
                         messages from $BRDCST.

    [NO]MAIL             Specifies notification of mail.

    NONE                 Disables all message classes.

    [NO]OPCOM            Specifies messages issued by the operator
                         communication process (OPCOM).

    [NO]PHONE            Specifies messages from the Phone utility.

    [NO]QUEUE            Specifies messages referring to print or
                         batch jobs issued by the queue manager.

    [NO]SHUTDOWN         Specifies messages issued from the
                         REPLY/SHUTDOWN command.

    [NO]URGENT           Specifies messages issued from the
                         REPLY/URGENT command.

    [NO]USER1 to         Specifies messages from specific user
    [NO]USER16           groups. (For information on setting up
                         user-written broadcast messages, see the
                         description of the $BRKTHRU system service
                         in the OpenVMS System Services Reference
                         Manual.)