% LICENSE: see LICENCE \section{Data Features} \subsection{FIG 1 Labels and FIG 2 Extended Labels} The specification offers two ways to carry ensemble, service and component labels: through FIG 1 and through FIG 2, specified in clauses 5.2.2.2 and 5.2.2.3 of ETSI EN 300 401~\cite{etsidab}. Most receivers are only able to show FIG 1 Labels encoded in the Complete EBU Latin character set (defined in ETSI TS 101 756 clause 5.2~\cite{etsidabtables}). Some are able to display Unicode FIG 1 Labels, encoded either in UTF-8 or UCS-2, and, as of early 2019, receiver support for FIG 2 Extended Labels is practically absent. The main downside of carrying Unicode FIG 1 Labels is the length limitation: 16 bytes will only encode eight characters in alphabets that require two bytes per character. FIG 2 supports up to 32 bytes labels to alleviate this. The intention is that new ensembles in countries requiring labels in non-latin alphabets transmit only FIG 2 Extended Labels, whereas currently operating ensembles keep transmitting FIG 1 Labels. This entices receiver manufacturers to support FIG 2 without impacting functionality of receivers currently in use. Transmitting both FIG 1 and FIG 2 is discouraged by the specification. The way FIG 2 is encoded has been redefined, which is why ODR-DabMux supports two variants: FIG 2 with character flag being the old variant, and FIG 2 with text control that will become the default variant. \subsection{Announcements} The ODR-DabMux multiplexer supports the insertion of FIG 0/18 and FIG 0/19 that are used to define and trigger announcements according to ETSI TR 101 496-2 Clause 3.6.8~\cite{etsitr1014962}. An example configuration is available in the ODR-DabMux repository, in \texttt{doc/advanced.mux}. The best known application for announcements is traffic information, but other kinds of announcements can also be signalled. ODR-DabMux allows triggering the announcements through the telnet and ZMQ remote control interfaces. \subsection{Service Linking} ODR-DabMux also supports the ability to inform receivers about other ways to receive a given service, through the FIGs 0/6, 0/21 and 0/24. FIG 0/6 communicates the identifiers of services linked together, 0/21 informs the receiver about other frequencies, and 0/24 includes information about other DAB ensembles carrying the linked service. Their interaction is outlined in ETSI TS 103 176~\cite{etsits103176}. You will find an example configuration in the ODR-DabMux repository, in \texttt{doc/servicelinking.mux}. % vim: spl=en spell tw=80 et