82
CSU/DSU MS DBU
Test Purpose
Testing using a test pattern is used for the following purposes:
• Transmits user-selected test pattern using an internal test-pattern generator,
and compares the received data using internal test-pattern detector to detect
if there are any errors on the DDS circuit.
• Injects errors and verifies that the unit transmits data across the
communication circuit to the remote unit.
• Helps determine from which direction the circuit is receiving errors.
Interpreting Test Results
If the unit is functioning properly, the test error count should be 0.
12.3.6 S
ELF
-T
EST
The self-test verifies current operation of the CSU/DSU MS DBU. It can be
performed at any time and is recommended if there is any question about
the DSU’s health.
Test Purpose
The purpose of this test is to determine if the DSU is functioning properly.
Interpreting Test Results
Once Self-Test is activated, the LEDs cycle on and off as the system runs
the self-test. A pass or fail status will be displayed on the LCD along with
a checksum indicating the current firmware revision.
12.4 Remote Unit Diagnostics
A remote CSU/DSU MS DBU can perform seven different tests; see Table 12-5.
Table 12-5. Remote Tests and AT Commands
Front Panel
AT Command
Description
1=2047 PATTERN
_T0&T7
Standard 2047 random data pattern
2=511 PATTERN
_T1&T7
Standard 511 random data pattern
3=STRESS PTRN #1
_T2&T7
DDS Stress Pattern #1
4=STRESS PTRN #2
_T3&T7
DDS Stress Pattern #2
5=STRESS PTRN #3
_T4&T7
DDS Stress Pattern #3
6=STRESS PTRN #4
_T5&T7
DDS Stress Pattern #4
7=DATA FROM DTE
&T6
Data from DTE