I have a LG plasma with serial RS232. I checked the service menu and only pin 2,3 and 5 are active. It seems that it is compatible with the MONITOR on the Beosystem 3.  Now, I bought a serial cable ( 2-3, 3-2, 5-5) and the the TV does not switch ON/OFF when I power my Beosystem 3.

Anyone has an ideea what kind of additional settings I have to make on my Beosystem 3??

thanks in advance for your precious help!