80
DSLAM modem manufacturer information is
displayed if available, but this feature is not
supported by all service types or manufacturers.
The 965DSP displays ‘unknown’ in this field if the
DSLAM manufacturer information is unavailable.
FEC, CRC, and HEC counts in each direction are
also displayed. FEC is the number of
Forward
Error Correction
events in each direction. These
are automatically corrected errors, and as such they
do not require re-transmission of data. CRC is the
number of
Cyclic Redundancy Check
errors detected
in each direction. These numeric checks indicate that
the ADSL data frame had one or more uncorrected
errors, so the data must be re-transmitted reducing
throughput. HEC is the number of Asynchronous
Transfer Mode (ATM) cell
Header Error Correction
events detected in each direction. ADSL normally
carries data in ATM format to remain synchronous
with data on the network. For the modem in the
965DSP, dummy 53-byte ATM data cells are inserted
to maintain proper timing with the DSLAM. The cell
header field integrity is checked separately since it
directs the data cell to its destination, and errors in
the header can cause the loss of an entire data cell.
Press the Alarms key to display more ADSL
modem connection information or the Status key to
return to the previous screen.
ADSL Alarms
This screen displays any detected ADSL link
alarm conditions. If a link alarm occurs at any time
during the connection, the link alarm history is set
to ‘Yes’ and remains in that state for the duration of
the connection.
