The interface between DAB-MUX and DAB-Transmitter?
Ensemble Transport Interface see ETSI ETS 300 799 Output stream of the DAB-multiplexer to the DAB-transmitter.
We noticed that a lot of misunderstandings exists between these two mnemonics used in DAB/DAB+ literature. Both ETI and EDI are used to interface the MUX output to the transmitter input.
ETI (Ensemble Transport Interface) is to be seen as a general name for the interface between the DAB-MUX and the DAB-transmitter. More specific we could talk about the ETI-LI (LI = Logical Frame). This frame is the basic ETI-frame which we need to be transported between the two devices DAB-MUX and DAB-Transmitter.
In addition we will see different standard and non-standard ways to transport this logical frame. These more specific interfaces will be defined by the extension following te mnemonic such as ETI-NI, ETI-NA and ETI-EDI.
EDI is only one of the available transport methods under which ETI can be transported. Most of the time the mnemonic is used on his own without the prefix ETI.
In fact we can say that both are ETI-signals although EDI is the envelope in which ETI is transported. Any transport of ETI over IP-networks will be called an EDI- interface because ETI will always be transported in an EDI-envelope when transported over IP-networks.
When we put data into a specific envelope we speak about encapsulation. This leads us finally to the name EDI which means Encapsulation of DAB Interfaces. Later we will see that the EDI-envelope will also be used for the STI-interface.
Further ETI can also be transported over other types of networks. Momentary two versions ETI-NI (Network Independent) and ETI-NA (Network Adapted) interfaces exist. We will look into this in the future.
Be aware that ETI is a mnemonic usually used in a broad range of meanings.
It does not say which underlying protocol will be used to transport it nor will it say something about the specifications of the physical interface (such as electrical and physical (connector) characteristics)!
In whatever format the ETI-information is transported it is important to know that the information need to be received every 24 milliseconds by the transmitter!
Conversion from from ETI-signals to (ETI-)EDI and vice versa is possible with commercial available equipment and ODR-software.