Juniper M120 - M120 External Clock Interface Ports on the Craft Interface; Table 8: External Clock Leds on the M120 Craft Interface

Two bi-color LEDs in the lower left and right corners of each port indicate port status.
The LED on the lower left as you face the craft interface indicates whether an external
clock source is present. The LED on the lower right as you face the craft interface indicates
if there is a fault. Table 8 on page 16 describes the external clock port LEDs,
Table 8: External Clock LEDs on the M120 Craft Interface
DescriptionStateColorLabel
External clock source is plugged into the port,
physical signal is present.
On steadilyGreenA
No external clock source is plugged into the port, no
physical signal is present.
Off–
Fault condition; external reference clock frequency
is out of the tolerance threshold deviation of 10
parts-per-million (PPM).
On steadilyYellowB
(Fault LED)
External clock signal is validated or no external clock
source is plugged into the port.
Off–
Related
Documentation
M120 Craft Interface Description on page 11•
• Maintaining the M120 Host Subsystem on page 266
• Replacing the M120 Craft Interface on page 184
M120 External Clock Interface Ports on the Craft Interface
Two external clock ports EXT CLOCK to the right of the craft interface alarm LEDs enable
you to connect the router’s internal Stratum 3 clock to an external reference clock source
with an RJ-45 cable. Using the router’s software, you can configure the internal Stratum
3 clock to synchronize with an external Building Integrated Timing System (BITS) or SDH
Equipment Timing Source (SETS) timing source by including a clock synchronization
statement at the [edit chassis] hierarchy level.
NOTE: Refer to the, Junos OS Administration Library for configuration
information.
The EXT CLOCK ports are labeled A and B. They accept two RJ-45 connectors for external
clock inputs with T1 or E1 reference clocks.
Two bi-color LEDs in the lower left and right corners of each port indicate port status.
The LED on the lower left as you face the craft interface indicates whether an external
clock source is present. The LED on the lower right as you face the craft interface indicates
if there is a fault. Table 8 on page 16 describes the external clock port LEDs,
Copyright © 2018, Juniper Networks, Inc.16
M120 Multiservice Edge Router Hardware Guide