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EXFO CableSHARK P3 VF/DSL Cable Qualifier User Manual

Page 20

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VF / DSL Cable Qualifier

8

SHDSL is designed to be more of a business solution than a residential service due to its symmetry. It can
be used as a T1 / E1 replacement technology and is also well suited for VoDSL solutions.

SHDSL has been developed to be spectrally compatible with other technologies within bundles of local
loops. SHDSL owes this to the Trellis Coded Pulse Amplitude Modulation (TC-PAM) line coding. This coding
technique maximizes the use of the lower frequencies of available loop bandwidth thus avoiding higher
frequencies where signals are more susceptible to crosstalk.

The key benefit of xDSL is that by transmitting on an existing telephone line, there is no cable installation
costs to be incurred whereas if fibre optic cable were installed to achieve the higher bit rates, the cable
installation cost would be great.