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VDSL
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VDSL or VHDSL (Very High Speed DSL) is an xDSL technology providing faster data transmission over a single twisted pair of wires. Compare HDSL (High data rate Digital Subscriber Line).
The maximum available bit rates are achieved at a range of about 300 meters (1000 ft), which allows for 26 Mbit/s symmetric access or up to 52Mbit/s down – 12Mbit/s up asymmetric access.
The Infineon 10Base-S™ (Ethernet over VDSL) technology delivers 10Mbps, full duplex Ethernet over existing copper wire infrastructure up to 4000ft/1200m.
Broadcom offers V-thernet solution.
Currently, the standard VDSL uses up to 4 different frequency bands, two for upstream (from the client to the telco) and two for downstream. The standard modulation technique is either QAM (Quadrature amplitude modulation) or DMT (Discrete multitone modulation) which are not compatible, but have similar performance. The current mostly used technology is DMT.
These fast speeds mean that VDSL is capable of supporting new high bandwidth applications such as HDTV, as well as telephone services (Voice over IP) and general Internet access, over a single connection.
A new VDSL standard is now available, named VDSL2.
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