Black Box CSU/DSU MS/DBU, Manual

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CSU/DSU MS/DBU
Table 4-4. DTE With Test Patterns Commands.
Front Panel AT Command Description
1=2047 PATTERN _T0 Standard 2047 random data pattern
2=511 PATTERN _T1 Standard 511 random data pattern
3=STRESS PTRN #1 _T2 DDS stress pattern #1
4=STRESS PTRN #2 _T3 DDS stress pattern #2
5=STRESS PTRN #3 _T4 DDS stress pattern #3
6=STRESS PTRN #4 _T5 DDS stress pattern #4
While this test is being performed, the CSU/DSU MS/DBU displays as shown
in Fig. 4-22.
DTE WITH TP
TEST ERR=XX
Fig. 4-22. DTE WITH TP.
The first line of the display indicates the type of test being performed. The
second line of the display indicates the number of errors accumulated by the
test pattern detector.
If errors occur during this test, the TEST ERR display can be reset to zero,
by pressing the “1” key. To verify proper operation of this test, single bit
errors can be injected into the transmitted test pattern by pressing the “2”
key. These errors appear on the TEST ERR display.
5=TEST PATTERN
The TEST PATTERN selection actually converts the local CSU/DSU
MS/DBU into a BERT tester for use in testing a remote CSU/DSU MS/DBU
over the actual communications circuit. With this test, the remote CSU/DSU
MS/DBU can be looped back in either the DTE and LOOP (LL) or the
LOOP ONLY (RT) mode. Instead of being looped back, the remote
CSU/DSU MS/DBU can operate in the data mode with data supplied from
an external BERT tester, or it can be operating in the TEST PATTERN mode.
The data paths for this mode are illustrated in
Fig. A-5 .
When this test selection is chosen, the system presents the same test
patterns as for DTE WITH TP.