# Status LEDs

Upon initial power-up, the components of the router run boot code, go through a series of self diagnostic tests, and synchronize with each other.

When the tests are complete, use the LEDs on each module to determine the status of the router. Observe the module LEDs on the front and rear components.

See Troubleshooting for information on the system's LEDs.

| Note: In the fan tray for the E320 Broadband Services Router, four of the eight fans turn on immediately upon initial power-up and the other four fans turn on after a delay of 10 seconds.