You will therefore receive that site from which someone is speaking. Except for the orgininating site, participating sites are muted unless there is a question or comment. Placement of the microphones is critical so that the entire room is coveraged without reverberation or other audio problems. Many sites, such as CBL, employ omnidirectional ceiling microphones. Besides the wide area of coverage, another advantage of using is that the wiring and microphones are out of the way and keeps the floor and tables clear of possible obstructions.
Some sites use directional table microphones.
You must speak towards one in order to be heard clearly. Similar to ceiling microphones, placement must be done in such a way as to provide total room coverage without audio problems. An unfortunate side effect is that you must be careful not to trip over the wires on the floor or move the microphones. Most sites have two monitors, one to display what is transmitted and the other to display what is received from a remote site. Some, like CBL, have additonal monitors so that the lecturer can view the remote sites while facing the local audience.