18
DSU 5600 User Manual
61200.078L1-1
Chapter 3. Test Modes
DTE and Loop Test (LL)
The DTE and Loop test is initiated at the local DSU 5600 and
allows independent testing of the separate sections of the DSU
5600. First, it allows the local DTE interface to be tested with data
from the terminal or test equipment. Second, it allows the loop
interface section of the local DSU 5600 to be tested from the
remote site over the actual communications circuit. Testing from
the remote end of the circuit is done with test data generated by
the remote DSU or terminal type test equipment.
The DTE and Loop test splits the DSU 5600 into separate DTE
and Loop interface sections and then loops the transmit data of
each interface back to its respective receive data. A block dia-
gram illustrating the loopback points and the signal paths for
this test is shown in Figure 3-3.
To initiate the DTE and Loop test, perform the following steps:
1. Press
Select
three times to turn
On
both the DTE and Loop
test indicators.
2. Press
Test
while these test indicators are
On
. The DTE and
Loop LEDs
Flash
during initialization of the test and turn
On
solid once the test is in progress.
To terminate this test, press
Test
.
