The AORTA-R has been extended with a data item counter and a FIFO (2Kx16 bit) storing counter values containing the number of data items received between the previous and the next control character; a FIFO is necessary to be able to buffer multiple counter values when more than one control character is present in the data not processed so far; every time a control character is received the counter value is entered into the FIFO and the counter is reset to 0.
The counter value does not include the control character itself, which is also written into the AORTA-R's data FIFOs.