Installation Guide

Installing the Data Module, Hardware Key, and Remote Maintenance Line
Chapter 3
Installing the Data Module 3-13
Power Up 3
When you first apply power to the 8400B Plus, the unit carries out a self-test to
verify that it is in working order. During the self-test, both LEDs will remain lit.
When the self-test is complete, the green LED will go off.
If the self-test passed, the red LED will remain lit. This indicates that the unit is
installed and ready for use.
If the self-test failed, the red LED will flash three times and then remain lit.
See the 8400B Plus Data Module User Guide to resolve configuration problems.
Note
If the red and green LEDs flash alternately, the data module cannot
communicate with the switch. In this case,
• Check the connections and wiring.
• Check the data module optioning.
• Test the data module from the DEFINITY system using
the “Status Data” switch command. You must enter the
data module extension number.