Cisco Network Interface Module for ISR 4000 - 2 FXS/DID + 4 FXO

The Cisco NIM-2FXS/4FXOP= is a voice network interface module that lets an ISR 4000 series router handle both internal analog devices and external phone lines without extra hardware. It supplies two FXS/DID ports for gear such as desk phones, fax machines, or a paging amplifier, and four FXO ports for connecting to the public switched telephone network. By hosting these connections directly on the router, the module simplifies cabling, reduces points of failure, and makes it easier to move toward IP telephony at your own pace.

Branch offices and midsize sites that still rely on a blend of VoIP and legacy analog services will appreciate the flexibility this module adds. You can keep existing analog endpoints in service while using the router as the central call-processing platform, or use the FXO ports as a failover path when a SIP trunk goes down. Either way, voice traffic enters the same secure, policy-controlled environment that already handles your data.

Installation is straightforward, and the online insertion and removal feature means you can add or replace the module without shutting down the router. That capability is especially valuable in locations where every minute of uptime counts, such as retail stores, healthcare clinics, or remote offices with limited on-site IT staff.

The module is purpose-built for Cisco ISR 4221, 4321, 4331, 4351, and 4431 routers, so it integrates cleanly with existing chassis slots, power budgets, and management tools. Once in place, you manage it through the same IOS XE interface you already use, keeping configuration and monitoring tasks familiar and efficient.

Highlights:

• Two FXS/DID ports for analog phones, fax machines, or paging systems
• Four FXO ports for connecting to the public switched telephone network
• Online insertion and removal allows module swaps with no downtime
• Compatible with Cisco ISR 4221, 4321, 4331, 4351, and 4431 routers
• Expands voice capacity while preserving existing investment in analog equipment