However, in nearly all cases, these solutions have relied on very expensive equipment and high cost data links. In order to better understand the options available for classroom use of teleconfernceing, it worthwhile to review the range of technical options available. Below, five levels or types of video technologies are discussed. Feedback to the uplink studio is often provided by a telephone voice-only link from each remote site to the studio. The remote sites can both see and hear the instructor, but the instructor cannot see the students.
Satellite systems provide one of the best quality video images of all of the technologies.
An example of this type of system is the Air Force TV network used to teach civil service contracting classes from Wright-Patterson Air Force Base in Ohio to Air Force bases around the world. High-end digital phone line video teleconference systems use digital phone lines to connect two or more sites together. They range from systems that use as few as three ISDN phone lines to as much as a full T1 line. These are true two-way video systems sharing both video and audio in both directions. Procurement costs for a high-end digital system for each side can vary widely depending on the sophistication of the system.