Nortel SONET AccessNode Manual page 47

Procedure 2-3 (continued)
Testing optical protection switching
Step
Testing automatic switching due to degradation of the optical signal
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Action
On the active OC-3/OC-12 circuit pack (G2), cause a degradation of the
optical signal by increasing the attenuation on the NT7E47 optical test cord,
until an automatic switch occurs.
The yellow loss-of-signal (LOS) LED on the G2 OC-3/OC-12 turns on. The
OC-3/OC-12 Protection screen displays an asterisk (*) in the AutoSw field of
OC-3/OC-12 G2. Traffic switches to G1, and its green (Active) LED turns on.
On the DS3/STS-1 test set, press the Start/Stop button twice to reset the
error count to zero.
The DS3/STS-1 test set indicates in process and displays 0 bit error.
To verify that DS3 or STS-1 continuity exists, press the Single Bit Error Inject
button three times on the DS3/STS-1 test set.
The DS3/STS-1 test set displays 3 bit errors received.
Decrease the attenuation of the NT7E47 optical test cord, until the signal is
restored.
The yellow LED indicating loss-of-signal (LOS) turns off when the input signal
level increases above the alarm threshold. The OC-3/OC-12 Protection
screen displays a dot (.) in the AutoSw field of G2.
Operate a manual switch to make the G2 an active circuit pack once again by
entering:
manual op g1 ↵
You are prompted to confirm the command.
y ↵
The green (Active) LED turns off at the G1 OC-3/OC-12 and lights on G2.
Traffic switches to the G2 circuit pack.
On the DS3/STS-1 test set, press the Start/Stop button twice to reset the
error count to zero.
The DS3/STS-1 test set indicates in process and displays 0 bit error.
To verify that DS3 or STS-1 continuity exists with the G2 OC-3/OC-12 as the
active circuit pack, press the Single Bit Error Inject button three times on the
DS3/STS-1 test set.
The DS3/STS-1 test set displays 3 bit errors received.
—continued—
AccessNode Site Testing Procedures 323-3001-221 Issue 2.0
DS3 tests, STS-1 tests, and optical in-bay tests 2-29