# LED Identification

The system's modules have two sets of status LEDs. The top set indicates overall router and module status. The bottom set indicates module-specific status, such as port status (line modules) or fan status (SRP module).

The number next to the port status LED on a line module corresponds to the number of the port on the I/O module. Some line modules have more port status LEDs than the number of ports on the I/O module. In these cases, only the LEDs for the corresponding ports on the I/O modules are active.

For example, an OCx/STMx line module can pair with either an OC3-4 or an OC12/STM4 I/O module. Consequently, the line module has four port status LEDs for OC3/STM1 operation. However, only the top set of port status LEDs IS active during OC12/STM4 operation.

Table 21 lists the functions of the module and port status LEDs.

Table 21: LED Identification and Activity Descriptions

LED Location | LED Label | LED Indicator | LED Color | OFF to ON | ON to OFF
--- | --- | --- | --- | --- | ---
All modules | OK | Module status | Green | Self-test passed | Failure detected
FAIL | Module status | Red | Failure detected | Diagnostic test running
ONLINE | Module status | Green | Module online | Module offine
All modules | REDUNDANT | Redundancy | Green | See Redundancy Status later in this appendix. NOTE: The REDUNDANT LED on the cOCx/STMx, FE-8, GE/FE, HSSI, and X.21/V.35 line modules is nonfunctional.
SRP module | POWER A OK | Power | Green | Power online on source A | Power off
| POWER B OK | Power | Green | Power online on source B | Power off
| FAN OK | Fan | Green | Fan online | Critical fan failure
| FAN FAIL | Fan | Red | Critical fan failure | Fan online
|  | NOTE: When the LED alternates between OK and FAIL at 10-second intervals, a non-critical fan failure exists.
| LINK | Ethernet | Green | Ethernet link up | Ethernet link down
| ACTIVITY | Ethernet | Green | Blinks when Ethernet traffic on link | No Ethernet traffic on link
Ethernet line modules | LINK | Ethernet | Green | Ethernet link up | Ethernet link down
ACTIVITY | Ethernet | Green | Blinks when Ethernet traffic on link | No Ethernet traffic on link
HSSI line module | SYNC | Port status | Green | If the port is configured as DTE, the LED lights when both the DCE and the clock source are available. If the port is configured as DCE, the LED lights when the DTE is available. | If the port is configured as DTE, the LED goes out when either the DCE or the clock source becomes unavailable. If the port is configured as DCE, the LED goes out when the DTE becomes unavailable.
YEL ALM | NOTE: This LED is not functional on the HSSI line module.
RED ALM | Port status | Red | If the port is configured as DTE, the LED lights when either the DCE or the clock source becomes unavailable. If the port is configured as DCE, the LED lights when the DTE becomes unavailable. | If the port is configured as DTE, the LE goes out when both the DCE and the clock source are available. If the port is configured as DCE, the LED goes out when the DTE is available.
X.21/V.35 line module | ACTIVE | Port status | Green | Port configured | Port not configured
LOOPBK | Port status | Yellow | Port in local loopback or remote loopback, depending on the type of connection. | Port not in loopback
ERROR | Port status | Red | Port is enabled or comes online | Port is disabled or goes offline
V.35 | Port status | Green | V.35 cable connected | V.35 cable disconnected
X.21 | Port status | Green | X.21 cable connected | X.21 cable disconnected
DCE | Port status | Green | DCE cable connected | DCE cable disconnected
DTE | Port status | Green | DTE cable connected | DTE cable disconnected
Other line modules | SYNC | Port status | Green | In frame | Not in frame
YEL ALM | Port status | Yellow | Far-end receive failure (FERF) exists | No FERF present
RED ALM | Port status | Red | Loss of sync/frame | In frame

The following figures show a representative module for each of the three variations:

- SRP module (Figure 1)
- Ethernet line module (Figure 2)
- Other line modules (Figure 3)

  Figure 1: SRP Module LEDs

  | Note: The primary SRP module illuminates the REDUNDANT LED only when the SRP module detects that there is a secondary or standby SRP module online. The standby SRP module monitors an activity signal from the primary SRP module to determine its state; it does not shadow the operations of the primary SRP module. If the standby SRP module detects that the primary SRP module is not active, it reboots the system and takes control. (ERX7xx/14xx models only)

  Figure 2: FE2 Module LEDs

  Figure 3: E3 and T3 Module LEDs