a multiplex carries many data streams each identified by its own PID
What's a PID?
A satellite transponder transmits an RF carrier which can carry a number of different signals. In "the good old days", one transponder carried one analogue TV channel using around 33MHz of RF bandwidth (varies depending on which satellite & system is used).
The same RF bandwidth can also transmit a digital data stream: say 40 Megabits per second. In the DVB TV system, this is enough for around 10 digital TV channels (av 4 Mbit/s each). The total data stream is known as a "multiplex" or "mux" as it carries multiple channels within it.
It can carry data channels as well as digital TV. This is how we use satellite to carry IP traffic to you. A data channel can carry any type of IP data: video streams (SatTV), IP files (SatKiosk) or your internet connection (SatSurf).
Each data channel is given a specific ID so that the receiver can select it out of the overall multiplex. This ID is called the Packet Identifier or Program ID: the PID. |
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Your receiver needs to know what PIDs it is looking for so it can select the right data channels. Some data receivers need to be programmed manually. Opensky will automatically set PIDs and other reception parameters for OS-Control compatible receivers such as the Manhattan DVB-IP1000.
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