Unfortunately if you have multiple rooms where you want to control the lights with a Beo4, you'll need a Lintronic in each room. For example you want to control a curtain, lights, and a fan in your main viewing room with a Beo4, and you have a link system in your bedroom or a BV8 and want to control the lights there as well with the Beo4, then you'll need a second Lintronic.

On the other hand, if you just want to control X-10 modules in other rooms from a Central location, then you only need one Lintronic and one Beo4.

While you can send some Lintronic commands via ML, I believe that these are limited to AV commands. I may be wrong about this.

I have two Lintronics, and will probably get a third in the future.