VDSL C
ONFIGURATION
10-8
Configuration Tables
•Channel Mode – Sets the channel mode to fast or interleaved.
(Default:Interleaved)
Interleaving protects data against bursts of er rors by using the
Reed-Solomon error correction algorithm to spread the errors over a
number of code words. A greater degree of interleaving provides more
protection against noise pulses, but increases transmission delay a nd
reduces the effective bandwidth.
For applications that cannot tolerate latency (for example, voice), use
the fast mode to disable the interleaving burst er ror correction method.
•Interleave Max Delay – Sets the maximum interleave delay.
(Range: 0-40, in units of 0.5 ms; Default: 4x0.5 ms or 2 ms)
Interleaving causes a delay in the transmission of data.
Setting the interleave delay to a value of zero disables interleaving.
Interleave delay applies only to the interleave (slow) channel and defines
the mapping (relative spacing) between subsequent input bytes at the
interleaver input and their placement in the bit stream at the interleaver
output. Larger numbers provide greater separation between consecu tive
input bytes in the output bit stream allowing for improved impulse
noise immunity at the expense of payload latency.
•Ham Band –
Sets the Handheld Amateur Radio (HAM) band that will be
blocked to VDSL signals based on defined frequencies. (Options: See
Table29-4, “HAM Band Notches,” on page 29-7. Default: none)
Using a HAM band mask prevents interference with other systems
(e.g.,amateur radio) that use narrow band transmission in the VDSL
frequency band. The selected frequency range will not be used to
transmit data on the VDSL line. You may need to specify a mask for a
specific radio frequency range if required by local regulations or if
specific incidents of interference are reported within a service area.
Note that the RFI-Band field includes information on bo th the
frequency range and the corresponding standard.