34
SHM-768K
• Use the internal Bit Error Rate Tester (BERT). Press the PATT button.
The ERR LED lights briefly to indicate that the LED is functioning. If any
bit error is encountered the LED blinks or remains ON.
• Step D: Perform Step C at both ends. If BERT test equipment indicates no
fault, but the data terminal indicates a fault, follow the manufacturer’s
test procedures for the data terminal and verify the cable connecting the
terminal and the SHM-768K. After completion of the test (or when the
fault has been corrected), restore the ANA push-button to the OFF
position by pressing it again. Proceed to the Communication Link Tests
(
Section 5.6
).
5.6 Communication Link Tests
5.6.1 R
EMOTE
D
IGITAL
L
OOPBACK
This test determines the performance of both the local and the remote
SHM-768K, and of the lines between the local and remote units.
• Step A: Press the REM (Remote Loopback) button, providing a loopback
at the remote SHM-768K (Figure 5-4). (This test can also be activated via
the pin on the DTE interface.) The TEST LED should light at both the
local and remote units.
• Step B: Perform the BERT test as explained in
Section 5.5
, Step C.
• Step C: If Step B indicates a fault, and if the modem test described
in
Section 5.4
was successful for both the local and remote modems,
the line circuits are not operating properly.
