In an effort to explain current usage patterns and to predict future usage, we look at three technologies -- audio (or telephone) conferencing, closed-circuit transmissions, and videotape -- in terms of four key performance measures: time expenditure, volume of matters, administrative and procedural adjustments, and the nature of the equipment. These four criteria emerged during a four-year study on civil and criminal courts' applications of telephone conferencing, but also seemed relevant for understanding the use and adoption of the other technologies. (Publisher abstract)