EXFO MaxTester 635 User Manual
Page 307
Running DSL/IP Tests and Viewing Results
Copper and VDSL2/ADSL2+ Multi-play Test Set
299
DSL Parameter Details
Parameter - Downstream/Upstream
Actual Data Rate displays the values at which the unit and CO are
connected, as negotiated during the training phase. The values
should represent what the CO was set to, unless the DSL link is
being subjected to high levels of noise/crosstalk.
SNR is the signal-to-noise ratio margin measured on the line.
Attenuation is line attenuation measured during the training
phase.
Note: DSL Param Details displays Attenuation for ADSL1/2/2+ only. See
Band Information for VDSL2 attenuation.
Capacity is the capacity of the line as a ratio of achieved bit rate
over the maximum attainable bit rate presented as a percentage
(%). A high value could mean that the link is nearing its maximum
capabilities while a low value could mean the link is being under
utilized (sometimes intentionally – verify your local DSLAM setup).
Maximum Data Rate displays the maximum attainable bit rates
that the circuit can handle as determined by the remote terminal
and CO during the training phase. Values can be greater than the
actual bit rate.
Output Power is the current transmit power level that is a measure
of the aggregated transmit power.
Latency is the path type, Fast or Interleave, set by the service
provider at the CO. The use of the interleaved path means greater
delay in the delivery of data but it is less susceptible to noise or
crosstalk due to increased Reed-Solomon coding and FEC
(forward error checking). The use of the fast path means little or
no delay in the delivery of data but it is more susceptible to noise
and crosstalk.