PDF of this tutorialDefinition
Asymmetric digital subscriber line (ADSL) is a new modem technology that converts existing twisted-pair telephone lines into access paths for high-speed communications of various sorts.
Overview
ADSL can transmit more than 6 Mbps to a subscriber—enough to provide Internet access, video-on-demand, and LAN access. In interactive mode it can transmit more than 640 kbps in both directions. This increases the existing access capacity by more than fifty-fold enabling the transformation of the existing public network. No longer is it limited to voice, text, and low-resolution graphics. It promises to be nothing less than an ubiquitous system that can provide multimedia (including full-motion video) to the entire country. ADSL can perform as indicated in Table 1.
| Data Rate (Mbps) | Wire Gauge (AWG) | Distance (ft) | Wire Size (mm) | Distance (km) |
| 1.5–2.0 | 24 | 18,000 | 0.5 | 5.5 |
| 1.5–2.0 | 26 | 15,000 | 0.4 | 4.6 |
| 6.1 | 24 | 12,000 | 0.5 | 3.7 |
| 6.1 | 26 | 9,000 | 0.4 | 2.7 |
Table 1. ADSL Data Rates As a Function of Wire and Distance
