| DSL technologies | |
|---|---|
| Standard | |
| ADSL | ANSI T1.413 Issue 2 ITU G.992.1 (G.DMT) ITU G.992.2 (G.Lite) |
| ADSL2 | ITU G.992.3 ITU G.992.4 ITU G.992.3 Annex J ITU G.992.3 Annex L |
| ADSL2+ | ITU G.992.5 ITU G.992.5 Annex M |
| HDSL | ITU G.991.1 |
| HDSL2 | |
| IDSL | |
| MSDSL | |
| PDSL | |
| RADSL | |
| SDSL | |
| SHDSL | ITU G.991.2 |
| UDSL | |
| VDSL | ITU G.993.1 |
| VDSL2 | ITU G.993.2 |
Rate-Adaptive Digital Subscriber Line (RADSL) is a variation of Asymmetric Digital Subscriber Line (ADSL) technology. In RADSL the DSL modem adjusts the upstream bandwidth to create a wider frequency band for the downstream traffic. Using this technique the line is more tolerant of errors caused by noise and signal loss.
As the frequency is adjusted, the upstream bandwidth may be markedly decreased if there is a large amount of line noise or signal degradation - this may reduce the upstream bit rate to as little as 64 kbit/s - the same speed as a single ISDN B channel.