There are many technologies being explored and used to deliver high-speed interactive services such as Internet access. ISDN, fiber optics and coaxial cable technology are often associated with the delivery of such services. There are numerous drawbacks that haved delayed full deployment and feasibility of these services. It depends upon the providers offering the services. If ADSL service prices resemble ISDN service prices, then one would expect ADSL to be favored for Internet access and other interactive applications.
Downstream traffic is similar between the two technologies.
Cable modem upstream traffic will in many cases be slower than ADSL, either because the particular cable modems are inherently slower or becasue of speed reductions caused by contention for upstream bandwidth. The big difference between ADSL and cable modems, however, is the number of lines available to each. Today there are approximately 12 million homes that can support two-way cable modem transmissions, and while the number will grow steadily, it will not catch up with the number of installed telephone lines for many years.