Cisco PWR-2821-51-AC enterprise networking (router/Catalyst switch/UCS families) Power Supply

The Cisco PWR-2821-51-AC is an AC power supply for the Cisco 2821 and 2851 Integrated Services Routers, second-generation ISR platforms widely deployed as branch and small-campus routers combining routing, security and voice-gateway functions. Because Cisco shared the internal power supply design across the 2821 and 2851 chassis, a single spare part covers both models rather than requiring separate model-specific units. This power supply is a routine like-for-like replacement when the original unit fails or shows signs of degradation, and 2821/2851 routers remain in active service across many established branch networks that have not yet migrated to newer ISR platforms. Tech-Star (UK-based, shipped worldwide) supplies Cisco power supplies. Confirm the exact router model and any redundant-power configuration before ordering.