ZyXEL Communications IES-1248-51 User Manual page 145

IES-1248-51 User's Guide
Discrete Multi-Tone (DMT) modulation divides up a line's bandwidth into tones. This screen
displays the number of bits transmitted for each tone. This can be used to determine the quality
of the connection, whether a given sub-carrier loop has sufficient margins to support ADSL
transmission rates, and possibly to determine whether certain specific types of interference or
line attenuation exist. See the ITU-T G.992.1 recommendation for more information on DMT.
The better (or shorter) the line, the higher the number of bits transmitted for a DMT tone. The
maximum number of bits that can be transmitted per DMT tone is 15.
The bit allocation contents are only valid when the link is up.
To open this screen, click Basic Setting, xDSL Line Data, Line Data.
In the screen shown, the downstream channel is carried on tones 48 to 255 and the upstream
channel is carried on tones 16 to 31 (space is left between the channels to avoid interference).
Figure 70 xDSL Line Data
Chapter 18 xDSL Line Data 145