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Connecting the M120 Router to an External Clocking Device


The M120 router contains two external clock input (EXT CLOCK) ports on the front panel of the craft interface labeled A or B.

To connect the router to external clocking devices, connect a cable with RJ-45 connectors to each external clock input port:

  1. Attach an electrostatic discharge (ESD) grounding trap on your bare wrist, and connect the strap to one of the ESD points on the chassis.
  2. Plug one end of the RJ-45 cable into the internal clock port on the craft interface.
  3. Plug the other end of the RJ-45 cable into the T1 or E1 external clocking device.
  4. Verify that the LEDs for the external clock inputs are lit steadily green.
  5. Configure the port. See the synchronization statement for M Series and T Series in the Junos OS Administration Library.
  6. Issue the show chassis synchronization command to check the status of the port.
    user@host> show chassis synchronization