What Is the Cisco CP-3905-PWR-KR=? Power Specifications, Use Cases, and Compatibility Insights

​​Overview of the CP-3905-PWR-KR=​​

The Cisco CP-3905-PWR-KR= is a ​​390W AC power supply module​​ designed for select Cisco Catalyst switches, including the Catalyst 3850 and 3650 series. It provides redundant, hot-swappable power to ensure continuous operation in environments where uptime is critical.

​​Key Technical Specifications​​

• ​​Input Voltage​​: 100-240V AC, 50/60Hz, with active PFC (Power Factor Correction) for energy efficiency.
• ​​Output​​: Delivers ​​390W of power​​ at 54V DC, supporting PoE+ (Power over Ethernet) for connected devices like IP phones, cameras, or wireless access points.
• ​​Redundancy​​: Supports ​​N+N or N+1 redundancy​​ when paired with a second power supply.
• ​​Compatibility​​: Works exclusively with Catalyst 3850-12X48U, 3850-24U, and 3650-24PD switches.

​​Primary Use Cases​​

High-Density PoE Deployments

The module is ideal for environments requiring ​​simultaneous power delivery to multiple PoE+ devices​​, such as offices with VoIP systems or campuses deploying IoT sensors.

Mission-Critical Networks

Redundant power supplies minimize downtime in healthcare, manufacturing, or financial sectors where network interruptions could disrupt operations.

​​Addressing Common User Questions​​

​​Q: Can the CP-3905-PWR-KR= support PoE++ (90W) devices?​​
A: No. It supports ​​PoE+ (30W per port)​​ only. For higher power demands, consider Cisco’s UPOE-compatible modules.

​​Q: Is the power supply hot-swappable?​​
A: Yes. Failed units can be replaced without shutting down the switch, ensuring uninterrupted service.

​​Procurement and Installation Notes​​

To avoid compatibility issues, verify your switch model before purchasing. For genuine Cisco components and warranty support, visit the “CP-3905-PWR-KR=” product page.

​​Final Observations​​

While the CP-3905-PWR-KR= isn’t the latest power supply in Cisco’s lineup, its reliability in PoE+ environments remains unmatched. Organizations with legacy Catalyst 3850/3650 systems should prioritize this module over third-party alternatives—especially when uptime and PoE stability are non-negotiable. However, for newer deployments, evaluating Cisco’s UPOE offerings might yield better long-term scalability.