Adjuncts and Peripherals
DS1/T1 CPE loopback jack
820 SI Installation and Upgrades
June 2004
Running the data test
1 Display the bit error count. At the management terminal, enter list meas ds1 sum location.
2 Step through Table 44 to troubleshoot.
3 Once you are fairly certain that the test is reporting no errors (after at least 1 error-free minute),
confirm that the 3-in-24 pattern error detector is operating. Enter test ds1-loop
location
inject-single-bit-error.
4 Display the bit error count again. At the management terminal, enter list meas ds1 sum
location.
Table 44: DS1 Troubleshooting
Condition Solution
The value of the
Test: cpe-loopback-
jack
field is Pattern 3-in-24
The loopback jack test is active.
The value of the Synchronized field is N Retry the test 5 times.
The value of the
Synchronized field
remains
N after 5 tries.
Excessive bit errors are likely. Check for
intermittent connections or broken wires in an
SPE receive or transmit pair, and repair as
necessary. Then repeat Step 1
.
The value of the Bit-error count field
is non-zero
Repeat Step 1 several times.
The value of the
Synchronized field is Y The DS1 circuit pack has synchronized to the
looped 3-in-24 pattern and is counting bit errors
in the pattern.
The value of the Bit-error count field
pegs at
75535 or increments by 100s or 1000s
each time you repeat Step 1
.
Suspect loose or corroded connections, severe
crosstalk, or impedance imbalances between the
two conductors of the receive or transmit pair.
Wiring may need replacement.
The value of the
Bit-error count field
is
0
There are no obvious wiring problems. Verify this
by repeating Step 1
at 1-minute to
10-minute intervals until you are certain.
If the test reports no errors for 1 minute, the error
rate is less than 1 in 10
8
. If the test reports no
errors for 10 minutes, the error rate is less than 1
in 10
9
.
Condition Solution
The value of the
Bit-error count field is
greater than 1
Replace the ICSU, and retest.
The value of the Bit-error count field is
still greater than 1 after you replace the ICSU.
Replace the DS1 circuit pack, and retest.
The value of the
Bit-error count field is 1 The test passed.