My company recently mandated a switch from Skype to Office Communicator for IM / voice chat.

While Skype was never the be all and end all of VOIP, it was at least usable.

With Communicator, if one person is talking, everyone else is basically silent (or as good as) so a normal conversation is impossible.

No one can interrupt anyone else, if two people start talking at once it's a crap shoot who gets to be heard and often the person who is inaudible doesn't know it.

There do not seem to be any client side settings to fix this. Is there anything that can be done server side or is it just rubbish?