AT&T System 25 - Manual (Page 63)

INSTALLATION
Check Performance of Cabinet Components
Each CP has three colored LEDs on the front panel that indicate whether it is
functioning properly or not. When a cold start is performed, the system
undergoes a series of self-tests and loads default translations.
Upon initial power application, each CP tests itself. The red LED on the CP
lights to indicate that the test is in progress. Once the CP passes its initial
tests, the red LED goes off. Then, after the main processor recognizes the
CP and can communicate with it, the green LED lights. When all green LEDs
are lighted, the testing and loading process is complete. This process takes
about 3 minutes.
1 . Make sure that both fans in each cabinet are on and operating.
2. Make sure that the green LED on the power unit behind the fan
assembly is lighted.
3. Check the CP LEDs. Table 2-D lists the LED status of each type of
C P .
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