The Future of DSL

For telephone companies to remain competitive in the telecommunications industry, they must innovate and seek new revenue streams from new technology. Upgrading of the old PSTN infrastructure is going on right now. It will take many years to upgrade the majority of the current copper cable capacity to fiber- optic cabling. Yet the higher bandwidth offered by fiber-optic cables will enable telcos to provide a wider range of services.

DSL is likely to remain a driving force for Internet connections for some time to come. Because it maximizes the otherwise - wasted frequency range of ordinary copper cables, DSL is a technology that can adapt to the current cabling of the PSTN, although it can provide that service only to a qualifying set of customers. As the fiber network grows farther out into the neighborhoods, you can expect to find that DSL technologies will become more widely available. As older copper segments of the PSTN are removed, so are obstacles that cause errors in DSL communications.

And with the improvement of the physical infrastructure of the PSTN, you should expect to see improvements and new types of xDSL technologies in the near future.

Chapter 18. Using a Cable Modem

SOME OF THE MAIN TOPICS IN THIS CHAPTER ARE

How Cable Modems Work

How Cable Modems Differ from xDSL Broadband Access

The Data Over Cable Service Interface Specification ( DOCSIS )

Which Should You Choose ”Cable or DSL ?

The two most popular methods for connecting home users and many small businesses to the Internet are DSL and cable modems. Both have their advantages as well as disadvantages. The preceding chapter explained how DSL works, and in this chapter you will learn about how cable modems work, as well as how they differ in many respects from DSL.

Although a cable modem connection might work for a home user or a small business, you must again think of the service provider before committing your network's connectivity to the Internet. Some cable companies are just great, providing quick resolution to problems, and others are not so great. Again, if you're not getting a good response (or better yet, response time) from your cable company at home, you might want to consider other options before using the same company as a link for your small business.

Note

Depending on where you live, you might not be able to get Internet access using a cable modem. Not all cable companies have the equipment necessary to provide this service. In that case you should consider using xDSL for a high-speed connection to the Net. Or you may live in a metropolitan area that offers both services. If that is the case, I suggest you read this chapter and Chapter 17, "Digital Subscriber Lines (DSL) Technology," and make your decision based on the topics covered. If you live in an area where neither service is available, you are out of luck, because "two tin cans and a string" uses amplitude modulation instead of digital signaling. Just seeing whether you're paying attention!

Another factor you might think about is the actual cost for cable modem services. Because many cable companies are now trying to maximize their revenues , since the cable TV market is pretty much saturated , you might find that you can get a special deal when subscribing to both cable TV and Internet access. If anything, you may be able to get a few months of cable-modem access at a reduced price.