A television signal is uplinked, amplified by a satellite in geostationary orbit, and then downlinked back to Earth. The signal can only be viewed if the receiving satellite dish is programmed with the specific transmission coordinates for that particular signal. This type of transmission is a one-way delivery system in which the site of origin transmits to a remote site.
Video is delivered through a regular phone line.
Picture quality in videoconferencing is compromised due to the compression of the signal. The instructional video market is huge. Educational programs are copied onto VHS format and marketed to schools, business, or the private sector. Local cable companies often provide community access television channels to the city. Using the Internet for delivery of educational instruction is a fairly recent phenomenon.