Hi Javi, I bought the cable for my Onkyo TX-RZ830. Unfortunately it didn't say anything about the size of the plug? So I would have to buy a jack adapter 3.5 to 2.5. Whether it works afterwards, I would have to test first. The specifications for the IR receiver jack plug 2.5 are missing. Without this information, I don't know if the plug will fit. You must check whether the Swisscom box has an IR input 2.5 or 3.5. TechniSat only lists their own compatible devices.
Sorry that I can't give you any better information.