
Chapter 1 Product Overview
Cable Side
Port LEDs
Table 
| LED Color | Meaning | 
| 
 | 
 | 
| Off | No link or port was administratively shut down | 
| 
 | 
 | 
| Green | Link present but not sending or receiving data | 
| 
 | 
 | 
| Blinking green | Activity. Port is sending or receiving data | 
| 
 | 
 | 
| Alternating | Link fault. Error frames can affect connectivity, and errors such as excessive | 
| collisions, CRC errors, and alignment and jabber errors are monitored for link | |
| 
 | faults | 
| 
 | 
 | 
| Amber | Port is blocked by Spanning Tree Protocol (STP) and is not forwarding data. | 
| 
 | After a port is reconfigured, the port LED is amber for up to 30 seconds as | 
| 
 | STP searches for loops. | 
| 
 | 
 | 
PoE LED
| Table  | PoE LED | 
 | 
| 
 | 
 | 
 | 
| Color | 
 | Meaning | 
| 
 | 
 | 
 | 
| Off | 
 | Not enabled | 
| 
 | 
 | 
 | 
| Green | 
 | Enabled and ports are functioning correctly | 
| 
 | 
 | |
| Alternating green and amber | Enabled but power is disconnected or has failed on a  | |
| 
 | 
 | 
 | 
| Blinking amber | 
 | Enabled but power is disconnected or has failed on a  | 
| 
 | 
 | 
 | 
| Amber | 
 | Enabled and a PoE circuit failure is detected | 
| 
 | 
 | 
 | 
Dual-Purpose  Port LEDs
The 
SD Flash Memory Card LED
| Table  | SD Flash Memory Card LED | |
| 
 | 
 | 
 | 
| Color | 
 | System Status | 
| 
 | 
 | |
| Off / blinking green | Transfer in progress | |
| 
 | 
 | 
 | 
| Blinking amber | 
 | Not present (slow blinking); unsupported SD flash memory card is | 
| 
 | 
 | detected (fast blinking) | 
| 
 | 
 | 
 | 
Cisco CGS 2520 Hardware Installation Guide
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