33
SHM-768K
5.5 Local Test—Analog Loopback
This test checks the performance of the local modem, the local data terminal
and the cables between them. It is performed separately at the local and the
remote sites.
Figure 5-3. Local SHM-768K in Analog Loopback.
• Step A: Press the ANA (Analog Loopback) button on the front panel
(Figure 4-1). (This test can also be activated via the pin on the DTE
interface.) The TEST LED should turn on. The SHM-768K transmit
output is now connected to its own receiver.
• Step B: Verify that the data terminal equipment is operating properly and
can be used for a test. If a fault is indicated, call a technician or replace
the unit.
• Step C: Execute the test using one of the methods described below:
• Use the DTE and check the echoed data stream.
• Use an external Bit Error Rate Tester (BERT) unit.
ASM-45
DATA
TERMINAL
XMTR
RCVR
DATA
CLK
CLK
DATA
ANA
DEPRESSED
LINE
