\label{Data_Unpacking}
The data stream contains SubEvent-IDs and SubSubEvent-IDs to identify the sender of each block of data. While SubSubEvent-IDs are equal to the network address of the corresponding board by design, the SubEvent-IDs can be choosen freely, but are defined to be equal to the network address of the board sending the SubEvent via Gigabit Ethernet. The first digit of each SubSubEvent-ID is sufficient to determine how the following data has to be handled:
\begin{description*}
-\item[0] Unpack as TDC data
+\item[0..1] Unpack as TDC data
+\item[5555] The only SubSubEvent-ID starting with 5 is 5555 at the end of each SubEvent, marking the beginning of the status information word for this SubEvent.
+\item[7] Special TDCs (like beam detectors, not part of the system under test)
\item[8] Skip this SubSubEvent-Header. Note: Only the header, the next word should be another valid SubSubEvent-Header.
-\item[C] Unpack as CTS data
-\item[5] The only SubSubEvent-ID starting with 5 is 5555 at the end of each SubEvent, marking the beginning of the status information word for this SubEvent.
+\item[C000] Unpack as CTS data
+\item[D..E] Other read-out formats, no TDC data included
\end{description*}
The data format is shown in later sections.