ISDN - Integrated Services Digital Network - A system that provides simultaneous voice, video, and high-speed data transmission through a single channel to the user's premises. ISDN is an international standard for end-to-end digital transmission of voice, data, and signaling. User networks can dial network channels of bandwidth in incriments of 64 kbit/s, up to 1536 kbit/s. Like any long distance service, rates are incurred by the call placer and per minute rates increase with distance from source.

VoIP - Video over Internet Protocol - A system that provides simultaneous voice, video, and high-speed data transmission through a single channel to the user's premises. IP is primarily used within Corporate LANs due to Quality of Service issues. User networks can dial network channels of bandwidth in incriments of 64 kbit/s, up to 1536 kbit/s. Once Corporate investment is made in infrastructure, there are no additional costs.

Voice activated - full screen image of location which is speaking (good if sharing visuals with other locations)

Continuous Presence -  provides continuous, simultaneous view of multiple small images of each of the sites (common formats include 4 Quadrants, 9 "tic-tac-toe" and "5 and 1" (five smaller on two sides of larger one)(excellent for maintaining visual contact with all particupants when no documents are shared)

Presenter - provides a full screen image of the originating site to all other sites, while the originating site receives smaller images of all other sites in either 4 quadrants or 9 tic-tac-toe (solution balancing the benefits of voice activated and continuous presence).