Introduction to DSL

This book covers the different types of DSL systems, why DSL is so important to telephone operators, and what services it can offer. It explains how DSL technology allows a standard twisted copper wires to provide broadband (1 Mbps+) and ULTRA broadband (10 Mbps+) data and high quality broadband data, digital telephone and IPTV television services. Explained are the key DSL network components including DSLAM and DSL modems and how they communicate with each other using Ethernet or ATM backbone networks. You will learn the basic ways to connect DSLAM to the backbone networks using bridged DSL, routed DSL, point to point protocol over ATM (PPPoA) and point to point protocol over Ethernet (PPPoE). DSL systems communicate by dividing the available bandwidth that can be transmitted on copper wires into multiple smaller discrete multi-tone (DMT) communication channels. These channels are sensitive to interference signals (such as AM radio) and installation challenges (such as wire loops) that can slow down DSL connections. You will also learn about how DSL signals can cause interference to other communication lines (signal egress). The different types of DSL including IDSL, HDSL, SDSL, ADSL, ADSL2, ADSL2+, Bonded ADSL and VDSL are covered. The differences in these systems are explained including maximum data transmission rates, the distance DSL can operate from the modem, and ratio of data transmission in each direction. Premises distribution options including wired Ethernet, Wireless LAN, phoneline data network, coaxial cable data distribution and powerline data are described.