Cisco PWR-3845-AC-IP/2
Cisco 3845 redundant AC/IP power supply
Product Highlights
What's Included
Maintaining continuous uptime on mission-critical branch routers demands a power infrastructure that can absorb failures without disruption. The Cisco PWR-3845-AC-IP/2 is a redundant AC/IP power supply engineered specifically for the Cisco 3845 Integrated Services Router, providing both system power and integrated inline Power over Ethernet (PoE) in a single hot-swappable module.
With a total output of 660 watts, this PSU delivers +5 V, +12 V, and –48 V DC rails — the –48 V output supplying up to 360 W of inline power to compatible EtherSwitch network modules such as the NME-XD-48ES-2S-P. This enables the Cisco 3845 to power IP phones and wireless access points directly through its switch modules without external PoE injectors, simplifying cabling and reducing equipment costs.
The "/2" designation identifies this unit as the redundant (second) power supply for the Cisco 3845 chassis. When paired with another PSU, the router operates in full redundant mode — if one supply fails, the other assumes the full load seamlessly. The unit accepts universal AC input (100–240 VAC, 50/60 Hz) and is both field-upgradeable and hot-swappable, allowing network administrators to service or upgrade power without scheduling a maintenance window. As part of the now end-of-life Cisco 3800 Series platform, the PWR-3845-AC-IP/2 remains a critical spare for organizations still operating these proven branch routers.
Features & Benefits
Redundant Power Protection
The Cisco 3845 chassis supports two internal power supplies operating in redundant mode. Installing the PWR-3845-AC-IP/2 as the second PSU ensures automatic failover — if the primary supply fails, the redundant unit takes over instantly with no service interruption. This is essential for branch offices and remote sites where router downtime directly impacts business operations.
Integrated Inline Power (PoE)
Unlike the standard PWR-3845-AC, the AC-IP variant includes a dedicated –48 VDC output rail that delivers up to 360 W of inline power to compatible EtherSwitch network modules. This enables 802.3af Power over Ethernet for IP phones and access points connected to the router's switch modules — eliminating the need for separate PoE switches or midspan injectors.
Hot-Swappable & Field-Upgradeable
The power supply can be removed and replaced while the Cisco 3845 router remains fully operational, provided a second PSU is installed. This hot-swap capability means zero-downtime maintenance. The unit is also field-upgradeable, allowing organizations to transition from a standard AC supply to an AC-IP supply as PoE requirements evolve.
Universal AC Input
Accepting 100–240 VAC at 50/60 Hz with auto-sensing, the PWR-3845-AC-IP/2 operates on standard power circuits worldwide. Whether deployed in North America, Europe, or Asia-Pacific, no voltage selector switch or external transformer is required — simplifying global deployments and spare-parts logistics.
Deployment Scenarios
Branch Office with IP Telephony
Organizations running Cisco Unified Communications at branch sites can use the PWR-3845-AC-IP/2 to power IP phones directly through EtherSwitch modules installed in the 3845 router. This consolidates routing, switching, and PoE into a single chassis, reducing rack space and cabling complexity.
High-Availability Branch Router Deployment
For branches where router downtime is unacceptable — such as retail point-of-sale locations or healthcare clinics — adding the PWR-3845-AC-IP/2 as a redundant PSU ensures the Cisco 3845 continues operating through a power supply failure. Paired with dual WAN links, this creates a resilient branch infrastructure.
Spare/Replacement for Aging Infrastructure
Many enterprises continue to operate Cisco 3845 routers well past their end-of-life date. Keeping a PWR-3845-AC-IP/2 on the shelf as a cold spare ensures rapid recovery if a power supply fails, avoiding extended downtime while sourcing parts for a legacy platform.
General
Electrical — Input
Electrical — Output
Features
Included Accessories
Compatibility Notes
Compatible Platforms:
- Cisco 3845 Integrated Services Router
- Cisco 3845 V3PN Bundle
- Cisco 3845C
Redundancy Notes:
- The Cisco 3845 supports internal redundant power with any combination of AC, AC-IP, and DC power supplies.
- When PoE redundancy is required, two AC-IP power supplies must be installed.
- Each AC-IP PSU integrates a –48 VDC internal supply for inline power to EtherSwitch modules requiring 802.3af PoE.
Note: This product is part of the Cisco C3800 platform which has reached End-of-Life (EOL). Cisco SMARTnet coverage may no longer be available. Verify service contract eligibility before purchase.
Downloads & Resources
Frequently Asked Questions
| Part Number | Product | Key Difference |
|---|---|---|
| PWR-3845-AC/2 | Cisco 3845 Redundant AC Power Supply (Non-IP) | Standard AC-only PSU without inline PoE capability — lower wattage, suitable when no PoE modules are installed. |
| PWR-3845-AC-IP | Cisco 3845 AC/IP Power Supply (Primary) | Same AC-IP power supply but ordered as the primary (first) unit rather than the redundant second supply. |
| PWR-3845-DC | Cisco 3845 DC Power Supply | DC-input variant for deployments with –48 VDC plant power (e.g., telco central offices). No inline PoE output. |
| PWR-3845-AC | Cisco 3845 AC Power Supply (Primary, Non-IP) | Primary AC-only PSU at 300W — no PoE support. Choose the AC-IP variant if inline power is needed. |