The yellow BEAT LED is located to the right of the Ethernet status LEDs. Under normal operation, this LED should blink about once per second. If the BEAT LED stays on constantly, does not light, or blinks very fast (more than once per second), contact your technical support representative for assistance.
Important: During boot-up, the heartbeat LED blinks in a 90% on, 10% off pattern. Do not remove power during this time, or data loss may result (NDIO module’s firmware upgrade may be in progress).