Several cameras at the originating site are available to capture the image of the instructor and/or the students there. Each receive site has, in general, only one camera, which captures the image of the students at that site.
Each remote site is connected separately to the originating site, where the video signals coming in are:
1) displayed along the back wall of the classroom, so that the instructor can see them at all times, and
2) made available to the engineers as potential material for display on the "program" signal, alone or in combination with other images. The "program" signal is sent out to all sites, where it appears on the television monitor at each site (including the originating site, where it is visible on at least one monitor). Since the "program" signal is the only signal received at the receive sites, students at those sites see themselves on television only when they are placed "on program."