If a television, say an Avant or BV5, receives a signal to turn to CD when there is no masterlink audio source connected or set up, what signals are sent over powerlink ? Does the TV just ignore the signal or does it get sent and the system assumes that you don't know what you are doing ? Currently in an audio only system the remote turns to TV mode even if there isn't one available, does this mean that it has sent the 'change over to the TV and send TV commands' ? 

Alex,

 it seems like you're asking 2 or 3 different questions here, so I'll do my best to untie the knot, and we can proceed from there if I've missed a/the point.

 
The B&O remote will send whatever command is appropriate for the button(s) you've mashed.  The issue is that there are at least 3 languages or command sets which might be sent; Audio, Video, and Link.  The B&O Masters (audio and video), and certain Link devices, can be instructed as to which language(s) they are expected to respond to.  So if you have a B&O TV set for 'Video only' (Opt. 1) it will ignore any Audio commands; but even if it is set to respond to both Audio & Video (Opt. 2), if there is no Audio device available, the command will result in no action/response because the TV will not be able to pass the command along.  If as you suggest, you have pressed a Video button on the remote in a room in which there is only an Audio Master (in Opt. 1), then, yes, it will ignore the remote untill an Audio command is sent again.

So far, all of the communication we're talking about here will happen via MasterLink, Master Control Link, or DataLink.  Your question mentions PowerLink, which seems oddly out of place...PL is a connection between a source and BeoLab speakers; it carries the audio feed and in some cases, the data needed to drive a display on the speaker...PL has essentially nothing to do with command and control of Masters.
 

Russ is right, you're getting several things confused. PowerLink is used to connect speakers to a Stereo or TV/BeoSystem, not to link the CD player to a TV or visa-versa.

Hi Russ, 

 From what I understand the powerlink connection transfers the source information however ? I understand that now that the remote will send whatever it is told to do. It is almost a separate entity  in that whatever i press on it, it sends. That is a useful bit of information. My thoughts on the Powerlink information that is sent comes from the Beolab 5's ability to switch to a digital input when it receives a CD command. If the TV was to pass this informatiion even whilst an audio masterlink wasn't present then it would possibly help me in my quest to integrate a B&O television a pair of beolab 5's and an AppleTv. Is this soft of stuff explained in the service manuals a bit better ?