16
DSU 5600 User Manual
61200.078L1-1
Chapter 3. Test Modes
DTE with Test Pattern (TP)
The DTE with Test Pattern (TP) test is similar to the DTE Only
test described previously. The DTE with TP test is initiated at
the local DSU 5600 and is used to independently test the opera-
tion of the DSU 5600.
To initiate the DTE with TP test, perform the following steps:
1. Press
Select
twice to turn
On
both the
DTE
and
PTRN
test
indicators.
2. Press
Test
while these test indicators are
On
.
To terminate this test, press
Test.
Instead of using data from the terminal or test equipment, this
test utilizes an internal test pattern generator and detector built
into the DSU 5600. The loopback point and the data paths for
this test are illustrated in Figure 3-2.
The internal test pattern generator and detector of the DSU 5600
operate with a 2047 data pattern. When this test is initiated, the
test pattern detector examines the receive data stream until
synchronization to the 2047 pattern is achieved. Once synchro-
nized, the detector continues to check the receive data and
reports any bit errors detected by turning
On
the
Error
LED.
Once a test is initialized with the internal test pattern generator
and detector, errors can be injected into the transmit data stream
by pressing
Select
and observed by watching the
Error
LED turn
On
for a brief period of time.
As previously mentioned, the DTE with TP test is automatically
performed during the self test sequence for the DSU 5600.
