8400B+

The red LED should be steady on. If the red and green LEDs are blinking, the unit is not communicating with the DEFINITY ECS. Check the wiring at the MDF, wall jack, and the 8400B+.

7400B+

The Power and TR LEDs should be steady on. If the Power and Data LEDs are blinking, the unit is not communicating with the DEFINITY ECS. Check the wiring at the MDF, wall jack, and the 7400B+.

7400A

Set the 7400A to DCE mode. The Power LED must be steady on. The DTR, DSR, DCD, RTS, and CTS settings must be highlighted in the display. If the Power LED is blinking, the data module is not communicating with the DEFINITY ECS. Check the wiring at the MDF, wall jack, and 7400A.