Don't try that adaptor.

Correct me if I'm wrong, but that adaptor is ethernet (network) and you need SpeakerLink (serial) which is completely different electrically. Potentially, it could cause harm to your speakers if you plug it in.

You have paid enough money to get your dealer to do it. Failing that, they should give you an RJ45 to serial cable which you can then connect to a USB/Serial converter. Failing that, if I can find it, you can have mine.

Meridian owner since 1992
Prime & PSU, Focal Elear headphones, Roon (ROCK 8Gi5 NUC), Explorer 1 & 2, F80. 200/203, various Sonos (via Roon).