
6
Troubleshooting Cisco 2800 Series Routers
OL-5789-01
  Reading Port and Module LEDs
Reading Port and Module LEDsThe port and module LEDs, located on the front panel of the router on the Cisco 2801 router and on the 
rear panel of the router on the Cisco 2811, Cisco 2821, and Cisco 2851 routers, enable you to determine 
router performance and operation. For an explanation of these LEDs see Table 2.
SYS ACT Off No packet transfers are 
occurring. 
Ethernet not active or not connected. Check Ethernet 
connections and make corrections as necessary.
Router not configured properly. Check configuration and 
make corrections as necessary.
Blinking System is actively transferring 
packets or is monitoring 
internal activities.
Normal indication. No action required.
CF Off The flash memory is not being 
accessed.
Normal indication. No action required. It is okay to remove 
the CompactFlash memory card if the CF LED remains off.
Solid green or 
blinking
The flash memory is being 
accessed.
Normal indication. No action required.
Caution: Do not remove the CompactFlash memory card 
while it is being accessed. 
Table1  System LEDs on Cisco 2800 Series Routers (continued)
LED 
Indicator State Meaning Possible Causes and Corrective Actions
Table2  LED Indicators on Cisco 2800 Series Routers
LED Indicator State Meaning Corrective Action
A = ACT Off Ethernet interface next to the 
LED is not receiving packets.
Ethernet not active or not connected. Check 
Ethernet connections and make corrections as 
necessary.
Router not configured properly. Check 
configuration and make corrections as necessary.
Solid or blinking 
green
Ethernet interface next to the 
LED is receiving packets.
Normal indication. No action required.
F = FDX Off Ethernet port nex t t o  th e L ED  
is operating in half-duplex 
mode.
Indication is for information only.
Solid green Ethernet port next to the LED 
is operating in full-duplex 
mode.
Indication is for information only.