paultielen: The av9000 in Room 1 and the mx7000 in room2..
When i'm in room 2 i will listen music what's playing from the masterpannel..
Yes, but ...
In any case you will need a BeoLink Video, a ML-cable, a ML-junction box and a
7-pin DataLink-cable.
The Master-Panel indicates, you have the very first AV 9000 version.
These versions use a 16-pin ML-cable and have to be modified to be
compatible to the recent 9-pin MasterLink-cable.
Consult a B&O service technician.