32
SHM-768K
Figure 5-2. Two BERTs Operating End-to-End.
5.4 Modem Self-Test
To verify that the SHM-768K is operating correctly, follow the instructions
below:
Step A
Press the ANA (Analog Loopback) button on the front panel. Both the TEST
and DCD LEDs should light. If the DCD LED does not light, verify that the
CARRIER jumper is ON or that the RTS signal is ON (high).
Step B
Press the PATT button. Verify that:
• DCD LED is still lit
• TEST LED is still lit
• RD LED lights
• ERR LED lights for a short period
The ERR LED should then go off. If it lights up or blinks, then the SHM-
768K is faulty and should be replaced. If the test executes correctly, restore all
the push-buttons and jumpers to the required position.
ASM-45
ASM-45
511
EXTERNAL
BERT
ERROR
ERROR
RCV
XMT
PATT
DEPRESSED
PATT
DEPRESSED
PATTERN
GENERATOR
PATTERN
TESTER
PATTERN
TESTER
PATTERN
GENERATOR
PATTERN
TESTER
