DiSEqC (TM) Analyser

This page will provide information about the DiSEqC(TM) Analyser USB stick.


A tool to analyse, learn or teach what DiSEqC is. The use of the USB device by it self is quiet self-explanatory; one F-connector must go to the Dish and the other to the STB, it doesn’t matter which one is connected to what.Watch the Video to see what result it can provide. You can also download the zip file that contains the application (.exe without virus since I am unable to produce one); and the FTDI driver to provide a Virtual COM Port CDM v2.12.14 WHQL Certified.

The goal of this here is not (yet) to describe in details what DiSEqC is; for more information about this protocol please read the specification released by Eutelsat here.

  • The functional description is simple as you can see in the block diagram. The two F connectors are just pass-through and the low frequency is filtered out and analysed by the MCU, then the result of the measurement is sent over the USB connection to the application.


  • User interface.


On the right side, a control panel allows to choose the Serial port where the USB stick is plugged, start and stop the analysis and clear the screen (when the log is too long, it doesn’t refresh smoothly).

The grey rectangle shows what is the polarisation voltage (13V here for Vertical), the 22kHz frequency, the Band and Port (in DiSEqC 1.0 it can A, B, C or D; in uncommitted DiSEqC it can be from 0 to 15). Polarisation and 22kHz is measured by the Hardware when the bus is idle (not sending commands). The Port number comes from the DiSEqC frame (DiSEqC 1.0); the DiSEqC 1.1 port is not reported there, only in the black window.

You can also add comments to the log. On the bottom, the different buttons, allow to record the raw data and reload them later on. The main screen is obviously the decoding of the DiSEqC frame. Not all DiSEqC version are implemented in terms of decoding but at least you would see which bytes were sent or received in case of bi-directional communication.

  • The Oscillo button will pop up a window that shows the DiSEqC frame as it would be displayed on an oscilloscope. By rolling, and moving the cursor on the bottom, one can focus on the interesting part of the trace.


The red line is actually the polarisation voltage and the yellow “blocks” are when the 22kHz is present. In this case there is 22kHz around 25 ms after Mini DiSEqC A which means Hi Band and the polarisation voltage is for Horizontal (>14V).

In the middle of the picture is where the DiSEqC message is sent. The bytes are highlighted by the kind of arrow.