VDSL Standards
VDSL uses up to 7 different frequency bands, which enables customization of data rate between upstream and downstream depending on the service offering and spectrum regulations. First generation VDSL standard specified both quadrature amplitude modulation (QAM) and discrete multi-tone modulation (DMT). In 2006, ITU-T standardized VDSL in recommendation G.993.2 which specified only DMT modulation for VDSL2.
| Version | Standard name | Common name | Downstream rate | Upstream rate | Approved in |
|---|---|---|---|---|---|
| VDSL | ITU G.993.1 | VDSL | 55 Mbit/s | 3Mbit/s | 2004-06-13 |
| VDSL | ITU G.993.2 | VDSL2 | 100 Mbit/s | 100 Mbit/s | 2006-02-17 |
Read more about this topic: Very-high-bit-rate Digital Subscriber Line
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