ATU MAC Address Database Number (DBNum) ======================================= If multiple address databases are not being used theses bits must remain zero. If multiple address databases are being used theses are used to set the desired address database number that is being used on the Database supported commands (atuOperation 0x03, 0x04, 0x05 and 0x06). On Get/Clear Violation Data atuOperation these bits return the atuDBNum value associated with the ATU violation that was just serviced.