Product manual

Maintenance, Fault signalling
Technical Product Manual - DCT1800-GAP
TD 92093 (1/LZBNB 103 108 R4D) / 2006-03-09/ Ver.C
© 2006
15
Fig. 3 LEDs in the system
3.6.1 LEDs on system boards
Each board has four LEDs at the top. The SLU has two times 4 LEDs because it consists of a SPU-
S and a CLU-S on one board, each with its own board controller and board address. The DTU also
has two times 4 LEDs because it contains a duplication of circuits with two board controllers, each
with their own address.
LED 1
LED 1 is the ‘Board powered’ LED, illuminating when the board is powered. On all boards this LED
shall be on.
LED 2
LED 2 is the ‘Watchdog reset’ LED, illuminating when the board controller receives a watchdog reset.
This LED normally only flashes during the power-on and 24-Hour test when the watchdog circuit is
being tested.
LED 3
LED 3 is the ‘Board not polled’ LED, illuminating when the board has not been polled by the CPU poll
processor for a period of time. As a result the CPU may not know the board any more, giving it the
state of PNP.
LED 4
LED 4 is the ‘Error’ LED, generally indicating an error on the board. On CLU, CLU-S, the CLU-S part
of the SLU board and DTU boards, this LED can be active for other reasons. Therefore, it may not
always be taken as an error indicator.
A CLU, CLU-S or the CLU-S part of an SLU board, will light LED 4 when base stations are in NEW
state, which means that a delay value is not yet programmed. The LED will turn off automatically after
programming the last base station of the CLU or CLU-S.
A DTU will light LED 4 when no trunk is connected. The DTU has no error, but the LED indicates that
no external clock is detected. The LED turns off as soon as a trunk is connected.
CPU System boards
(DTU 2x)
Power Reset LED
1
LED
2
Base station
Green
Red
SLU
LED1
LED4
LED1
LED4
LED1
LED4
LED1
LED5
LED6
LED4
SPU-S
part
CLU-S
part
LED1
LED2
003