EXFO MaxTester DSL - Manual (Page 38)

MaxTester DSL Test Results 32
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Interleave Depth defines the number of bits (or bytes) in each block of
data.
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Bitswap specifies the status of the bit swapping mechanism - Active, Not
Active or Unknown - swapping bits from tone m to tone n to prevent
modem retraining.
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Trellis or Trellis Coded Modulation (TCM) is a type of convolutional code
which utilizes parity bits on each symbol within a continuous data stream.
When the line is connected, Trellis displays either On or Off.
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Phy-R is Broadcom proprietary Physical Layer Retransmit technology which
is used to overcome impulse noise.
DSL Statistics
The DSL Statistics tab allows you to view transfer mode statistics and DSL counters.
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DSL Counters lists the Local and Remote results for
the following counters:
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CRC is the cyclical redundancy check
Interleaved/Fast counter.
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FEC is the Reed Solomon forward error
correction.
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FEC Seconds is the number of seconds when FEC
is detected.
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Error Seconds is the number of seconds when
code violation is detected.
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HEC is the header error check (HEC)
Interleaved/Fast counter. Available only in ATM
connection mode.
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Parameter - Received/Transmitted
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Bytes records the number of active (non-idle) PTM/ATM cells or frames on
a channel.
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Packets displays the number of packets.
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Transport Type options include PTM (packet transfer mode) and ATM
(asynchronous transfer mode).
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Sync Loss Count is the number of times the unit lost synchronization.
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PTMCRC is the number of CRC (cyclical redundancy check) errors of the PTM.
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PTMCV is the number of CV (code violation) errors of the PTM.