User's Manual

Chapter 16 Test Results
DSL Results
SmartClass TPS User’s Guide
May 2014 22035456, Rev 001 127
Table 27 lists common noise sources and the corresponding frequencies and tones.
ATM results
ADSL typically transports data over ATM (Asynchronous Transfer Mode) circuits. (VDSL, as well as
some ADSL systems transmit over packet mode circuits.) The ATM category provides results that
help you troubleshoot these connections. These results are helpful if IP pings are not working, but
your tester is still sending and receiving ATM cells.
Cell Count
Table 28 describes the ATM Cell Count results.
Errors
Table 29 describes the ATM Error results.
Table 27 Noise sources and tones
Noise Source Noise Frequency (kHz) Tone # Tone Frequency (kHz)
ISDN BRI 40 9 38.8125
HDSL passband center 196 45 194.0625
HDSL passband max 392 91 392.4375
HDSL2 274 64 276
T1 passband center 772 179 772
E1 passband center 1024 237 1022
Table 28 ATM Cell Count results
Result Definition
User Number of cells that contain user data.
OAM Number of cells that contain OAM data.
Bad Number of bad cells received.
Dropped Total number of dropped cells. The ATM network will discard or “drop” erred cells
which must then be retransmitted (this is done automatically). The SmartClass Triple
Play Services counts the number of ATM cells and how many were dropped, giving an
indication of service quality.
Table 29 ATM Error results
Result Definition
HEC Header error correction. Errored ATM cell headers that have been automatically cor-
rected.
OCD Out-of Cell Delineation. Occurs when cells fail to contain a valid HEC (Header Error
Check)
LCD A Loss of Cell Delineation. Initially triggered when an OCD condition occurs and
doesn't clear for more than 4ms.