Digital vs. analog information - digital data are represented by discrete values. Analog information is represented by ranges of values, and is therefore less precise. Computers use digital data. Because your computer only understands digital data, your modem converts analog data to digital and vise versa. The bandwidth is shared by all the users, so the effective speed of communication depends on how many people are currently using the network.
Ethernet is the primary type of networking used in the Internet.
Dedicated Lines - special cables used only for videoconferencing, usually within an office or school. Compression - the computer equivalent of saying the same thing with fewer words. The information in a file or a picture, for example, can be rearranged so less data are needed to represent it. Sometimes a little information is lost during compression. Frame - one of the still pictures that make up a video.