The AORTA-R-V1 generated interrupts only depending on the amount of data received (using the status of the data FIFO flags as interrupt source), with the AORTA-R-V2 it is possible to mix 'normal' data with control characters (the ones marked 'free for user' in table 1) and get an interrupt for every control character received, making it possible e.g. to mark 'end-of-event' which in combination with the data item counter value retrieved from the counter FIFO enables the user to process the datastream 'event-driven' instead of 'quantity-driven'.
Of course this requires that the event size must be smaller than the size of the data FIFO (=8 K data items).
In addition separate interrupts have been added (in VME as well as XdBeX) for 'no data present on fiber' (NODATA) (generated after a timeout period of about 3 seconds after the last data item has been received) and for 'optical fiber disconnect' (NOSIGNAL) (when the optical fiber cable becomes disconnected or breaks).
The control character interrupts and the NODATA and NOSIGNAL interrupts can each be enabled/disabled by setting/resetting a bit in a register (see table 6).