At least a two page paper in current APA format that discusses how each of these technologies are Write used in DSL communications, and compares all four to provide the major capabilities, shortfalls, and weaknesses of each.

To find out more technical details about DSL, investigate the different modulation techniques that are used to transmit DSL signals. Although these techniques are quite complex, they are an interesting study in the technological advances necessary to provide high-speed data streams over ordinary copper twisted pair wire. Using either the Internet or hard copy sources (which, by necessity, must be fairly current), look up the following four technologies. All four are being used somewhere on DSL circuits:

■Discrete multitone technology (DMT)

■Carrierless amplitude phase (CAP) modulation

■Multiple virtual line (MVL)

■Echo cancellation