Even though Cisco announced the End-of-Life and End-of-Sale for the cost-effective 800 Series Integrated Services Routers several years ago, these devices remain actively deployed in numerous branch offices and small to medium-sized businesses. Their durability and continued software support mean many organizations still rely on them for critical connectivity. A common challenge users face involves correctly powering these devices, especially when implementing Power over Ethernet (PoE) capabilities. One user, kasper123, recently highlighted a typical yet confusing scenario involving a Cisco 891FW router. The core of the issue revolved around identifying the correct high-wattage power supply unit needed to support PoE functionality on this specific model. This situation underscores a broader need for clear guidance on hardware compatibility and upgrade paths for maintaining older yet functional network infrastructure, ensuring businesses can continue to operate without unexpected downtime or costly miscalculations.
Understanding the Cisco 891FW Power Supply Dilemma
The problem presented was specific: a user had a Cisco 891FW router with a unique, rectangular 4-pin power connector, unlike the standard power inputs on other models. They needed to source the appropriate external power supply to not only turn the router on but also to deliver sufficient power for PoE to connected devices like phones or wireless access points. The confusion often arises because different hardware generations and configurations within the same router family require different power bricks. Using an underpowered supply can lead to unstable operation, while an incorrect connector type simply won’t fit, halting deployment before it even begins.
80W vs. 125W: Selecting the Correct Power Supply
For the Cisco 890 series routers, two main power supply options support PoE: an 80-watt unit and a 125-watt unit. The choice isn’t arbitrary; it’s determined by the router’s hardware generation and internal configuration. Older versions of these routers were designed to use two separate power supplies simultaneously—a standard 60-watt unit for the router’s core functions and an additional 80-watt unit dedicated solely to providing Power over Ethernet. In contrast, newer revisions of the hardware, like the one kasper123 encountered, consolidated this power delivery into a single, more robust 125-watt power supply that uses a distinctive 4-pin connector. This design simplification reduces cable clutter but requires ensuring you have the matching component.
The Critical Role of the PoE Daughter Card
Simply providing enough wattage isn’t enough. The physical ability to send power over Ethernet cables is handled by an internal hardware component called the PoE daughter card. This card is not always included as a standard feature. If your router was originally ordered without PoE capabilities, it will lack this card. You can install it later as an upgrade. The official Cisco product ID for this upgrade kit is 800-IL-PM-4=. It’s crucial to understand that installing a higher-wattage power supply without this daughter card will allow the router itself to boot and operate normally, but the PoE ports will remain inactive and unable to power any downstream devices. The power supply provides the capacity, but the daughter card provides the functionality.
How to Verify Your Router’s Internal Hardware
Before purchasing a new power supply or upgrade kit, it’s wise to verify what’s already inside your router. If the device can power on, the easiest method is to use the Cisco IOS command show inventory raw. This command will output a detailed list of all internal components. Scan this list for mentions of the PoE daughter card or the part number 800-IL-PM-4. If the router is completely without power and you cannot run any commands, the only alternative is to physically open the chassis—after ensuring all power is disconnected—and visually inspect the motherboard for the presence of the add-in card.
Community Insights and Practical Installation Tips
Other network administrators who have navigated this process provide invaluable advice. One user, Bascheew, shared a complete parts list for the upgrade, which includes not only the daughter card and power supply but also the necessary mounting hardware like specific standoffs and screws that ensure the card is securely fitted. Another user, Brian Scheewe, detailed his experience adding PoE to a C891FW-A-K9 model. He emphasized the importance of using Cisco’s official commerce platform to generate a valid configuration, ensuring all compatible parts are ordered together. His shipment included the LiteOn-manufactured PWR-125W-ACpower supply, a common OEM model for Cisco.
Successfully upgrading or maintaining the Cisco 891 series for Power over Ethernet demands careful attention to hardware compatibility. The process involves verifying your router’s generation, confirming the presence of the essential PoE daughter card, and sourcing the correct, high-wattage power supply with the right connector. While these routers may be older, understanding their specific requirements allows businesses to extend their service life effectively and reliably. For those seeking guaranteed compatible hardware, detailed configuration guides, or alternative modern solutions that offer similar functionality, a visit to telecomate.com provides access to a wealth of resources and expert support to ensure your network’s power needs are met without any costly errors or operational interruptions.
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