Thank you for your inquiry.
Each infrared remote control uses infrared signals in a predetermined her window. The remote control extension IR-83 is normally forward suitable incoming signals in this window accordingly, but some manufacturers seem, especially in the newer series of digital receivers, to lay their signals outside this window. Thus, then, of course, the use of the remote control extension, as evident in your case, no longer exists.
We regret you not being able to help here. If you have further questions we are at your disposal, of course. "
For me it was the HUMAX IHD PVR-C, which was not working.