LED functions The unit's various LEDs are designed to provide visual feedback as follows: Power LED The Power LED is located on the right side of the Base Cabinet, and is illuminated when power is being applied to the system. This LED blinks periodically to indicate that the main processor is operational. Port LEDs The Port LEDs are located above their respective connectors on each installed port card. Each LED is illuminated when any port on its associated port card is in use. Note: Disconnecting a connector when its respective LED is lit will disconnect any of its ports that are in use. Upon power-up, approximately five minutes are required for the system to configure. The Power and Port LEDs will blink three times to indicate that the power-up sequence has been completed. Note: When the LED on a DLC1 is . . . • . . . blinking, the T1/PRI circuit is out of service. • . . . not lit at all, the T1/PRI circuit is in service but is idle. • . . . lit solidly, the T1/PRI circuit and/or a station on the card are in use. ESI Presence Management installation For information on installing ESI Presence Management, see its Installation Manu