Juniper BT8A78CH1, Hardware Overview And Installation Manual

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of optical density sufficient to reduce the exposure levels below the appropriate
maximum permissible exposure, unless it has been verified that all optical transmitters
are turned off and will remain off during the installation or service operation.
•
During all splicing operations that require viewing the end of a fiber of an SG3a, SG3b
or SG4 optical-fiber communication systems, the laser source on the fiber involved
shall be de-energized or viewing the systems incorporating personal protection shall
be employed. A responsible person(s) shall verify that the system is de-energized
before splicing proceeds. Where applicable, ensure compliance with lockout/tagout
requirements of OSHA Standard 29 CFR Part 1910.147.
Laser Safety
CAUTION: USE OF CONTROLS OR ADJUSTMENTS OR PERFORMANCE OF
PROCEDURES OTHER THAN THOSE SPECIFIED IN THIS GUIDE MIGHT
RESULT IN HAZARDOUS RADIATION EXPOSURE.
Due to the potential safety hazard that is posed by high power outputs of optical modules,
the BTI7800 supports automatic power shutdown (APSD) and automatic power reduction
(APR) to shut off or reduce the output powers when a fiber is cut.
Table 3: Timing of APSD and APR Operations
Output Level After
Activation
Activation Time Laser Safety Mechanism
< 20 dBm < 2.0 seconds APR
< 20 dBm < 2.0 seconds APSD
•
Laser Safety: Automatic Power Shutdown on page 22
•
Laser Safety: Automatic Power Reduction on page 24
• Safety Rating and Label on page 25
Laser Safety: Automatic Power Shutdown
Automatic power shutdown (APSD) applies to fiber spans between optical equipment.
When a fiber is cut, APSD causes both ends to automatically shut down its high power
lasers, allowing maintenance personnel to repair or reconnect the fiber safely. Once the
span fibers are repaired or reconnected, the lasers are automatically turned back on and
traffic is automatically restored.
WARNING: APSD is performed in software on the service module and is
disabled whenever the service module undergoes a warm or cold reload. In
a cold reload, the lasers are turned off and are in a safe state. In a warm
reload, however, the lasers remain on while APSD is disabled.
Copyright © 2019, Juniper Networks, Inc. 22
BTI7800 Series Hardware Overview and Installation Guide