Configuring the SHDSL LIM
Diagnostic internal, external, and bit error-rate tests
Stinger®
SHDSL 48-Port and 72-Port Line Interface Modules (LIM) Guide
1-23
Following is an example of setting up a BERT:
[in LINE-DIAG/{ shelf-1 slot-4 1 }]
admin> set bert-timer = 5
admin> set bert-enable = yes
admin> write
LINE-DIAG/{ shelf-1 slot-4 1 } written
To view the status and results of the BERT, display the contents of the
line-diag-stat
profile for the tested line.
Configuring an external diagnostic test (EDT)
The external diagnostic test (EDT) feature puts the DSL modem into loopback mode.
If a complete circuit is established, you can then send a data stream from an external
device (such as a network traffic generator) through the trunk to the modem. The
modem loops back the data stream to the external device, where it can be analyzed.
The
loop-back
parameter is described in “Configuring port settings for SHDSL” on
[in SHDSL/{ shelf-1 slot-2 1 }:line-config]
loop-back = none
You configure a line for external diagnostic testing by putting it into loopback mode,
as shown in the following example:
admin> read shdsl {1 1 1}
SHDSL/{ shelf-1 slot-1 1 } read
admin> set loop-back = analog
admin> write
Digital loopback
When a line is enabled for digital loopback, data is looped only at the digital circuitry
of the modem. Data does not reach the analog circuitry, as shown in Figure 1-5.
Figure 1-5. Digital loopback
DSL loop
Analog
(hybrid)
circuitry
Digital
circuitry
DSL loop
