ADTRAN DSU 56/64, User Manual

Page: 36 / 44

Chapter 3. Test Modes
3-8 DSU 56/64 User Manual 61200062L1-1
Test Pattern (PTRN)
When the PTRN test is initiated, the local DSU 56/64 uses the
integral test pattern generator to transmit a standard 2047 test
pattern to the DSU on the far end of the circuit. The local DSU 56/
64 then examines the received data for the standard 2047 pattern.
Once this pattern is detected and synchronization is achieved, the
E
RROR
indicator is turned off. The E
RROR
indicator turns on when
errors in the receive data pattern are detected. While this test is
active, errors can be injected into the transmit data stream by
pressing the
S
ELECT
push-button. The PTRN LED flashes during
initialization of the test and turns on solid once the test is in
progress.
To initiate the PTRN test, perform the following steps:
1. Press S
ELECT
seven times to turn on the PTRN test indicator.
2. Press the T
EST
switch while this test indicator is on.
3. To terminate this test, press T
EST
.