Related Documentation
T4000 Craft Interface LEDs
Figure 1 shows the LEDs on the craft interface.
Figure 1: Front Panel of the Craft Interface

Alarm LEDs
Two large alarm LEDs are located at the upper left of the craft interface. The circular red LED lights to indicate a critical condition that can result in a system shutdown. The triangular yellow LED lights to indicate a less severe condition that requires monitoring or maintenance. Both LEDs can be lit simultaneously.
A condition that causes an LED to light also activates the corresponding alarm relay contact on the Connector Interface Panel (CIP). The LCD on the craft interface reports the cause of the alarm.
To deactivate red and yellow alarms, press the button labeled ACO/LT (for “alarm cutoff/lamp test”), which is located to the right of the alarm LEDs. Deactivating an alarm turns off both LEDs and deactivates the device attached to the corresponding alarm relay contact on the CIP. However, the LCD continues to report the alarm message until you clear the condition that caused the alarm.
Table 1 describes the alarm LEDs and alarm cutoff button in more detail.
Table 1: Alarm LEDs and Alarm Cutoff/Lamp Test Button
Shape | Color | State | Description |
---|---|---|---|
![]() | Red | On steadily | Critical alarm LED—Indicates a critical condition that can cause the router to stop functioning. Possible causes include component removal, failure, or overheating. |
![]() | Yellow | On steadily | Warning alarm LED—Indicates a serious but nonfatal error condition, such as a maintenance alert or a significant increase in component temperature. |
![]() | — | — | Alarm cutoff/lamp test button—Deactivates red and yellow alarms. Causes all LEDs on the craft interface to light (for testing purposes), when pressed and held. |
FPC LEDs
Each FPC slot has two LEDs that indicate its status. The FPC LEDs, labeled FPC0 through FPC7, are located along the bottom of the craft interface.
Table 2 describes the functions of the FPC LEDs.
Table 2: FPC LEDs
Label | Color | State | Description |
---|---|---|---|
FAIL | Red | On steadily | FPC has failed. |
OK | Green | On steadily | FPC is functioning normally. |
Blinking | FPC is starting up. |
Host Subsystem LEDs
Each host subsystem has three LEDs, located on the upper right of the craft interface, that indicate its status. The LEDs labeled HOST0 show the status of the Routing Engine in slot RE0 and the CB in slot CB0. The LEDs labeled HOST1 show the status of the Routing Engine in slot RE1 and the CB in slot CB1.
Table 3 describes the functions of the host subsystem LEDs.
Table 3: T4000 Host Subsystem LEDs
Label | Color | State | Description |
---|---|---|---|
FAIL | Red | On steadily | Host is offline. |
OK | Green | On steadily | Host is online and is functioning normally. |
MASTER | Green | On steadily | Host is functioning as the master. |
SIB LEDs
Each SIB has two LEDs on the craft interface that indicate its status. The SIB LEDs, labeled SIB0 through SIB4, are located on the upper right of the craft interface. The ACTIVE LED on the SIB faceplate is not replicated on the craft interface.
Table 4 describes the functions of the SIB LEDs.
Table 4: SIB LEDs on the Craft Interface
Label | Color | State | Description |
---|---|---|---|
FAIL | Red | On steadily | SIB has failed. |
OK | Green | On steadily | SIB is functioning normally. |