ADTRAN DSU 56/64, User Manual

Page: 30 / 44

Chapter 3. Test Modes
3-2 DSU 56/64 User Manual 61200062L1-1
If an
E
PROM
C
HECKSUM
failure is detected during self test,
CS
,
ALM
,
PTRN
, and
E
RROR
indicators all flash at the end of the self
test.
NEAR END TESTS
The local DSU 56/64 can perform the following near end tests:
• DTE Only
• DTE with Test Pattern
• DTE and LOOP (LL)
• Loop Only (RT)
DTE ONLY TEST
The DTE O
NLY
test can test both the DTE interface of the local DSU
56/64 plus its loop transmitter and receiver. For this test, the loop
transmit data is connected to the loop receive data at a point close
to the physical network interface.
The loopback point and the signal paths for this test are shown in
Figure 3-1.
Figure 3-1. DTE Only Test Diagram
56/64 DSU
DTE
Receive
Interface
DTE
Transmit
Interface
Loop
Transmit
Interface
Loop
Receive
Interface
DTE
Only
TD
DTE or Test
Equipment
Interface
Network
Interface
RD
Loop TX
Loop RX