Cisco NIM-2FXS/4FXO — Analog Voice Network Interface Module

Save up to 80% over list price on this fully tested, refurbished Cisco NIM-2FXS/4FXO voice module. Add 2 FXS and 4 FXO analog voice ports to your Cisco ISR 4300 or 4400 Series router — ideal for connecting legacy phones, fax machines, and PSTN lines to your VoIP network. Backed by Reef Telecom's industry-leading 10-year warranty.

Key Features

• 2 FXS/FXS-E/DID Ports: Connect analog phones, fax machines, or key systems directly to your IP network
• 4 FXO Ports: Seamless PSTN and PBX line connectivity with caller ID and battery reversal detection
• Onboard DSP: Dedicated digital signal processor — no separate PVDM required on the router motherboard
• Echo Cancellation: Up to 128ms echo-tail length for clear voice quality in demanding network conditions
• Codec Support: G.711, G.729a, G.726, G.723, iSAC transcoding, and T.38 fax relay
• Protocol Support: SIP, SCCP, H.323, and MGCP for flexible UC deployment
• Hot-Swappable: Online insertion and removal (OIR) — no router downtime during installation
• Security: SRTP, TLS, and Secure Unified Communications Manager Express authentication

Specifications

• Part Number: NIM-2FXS/4FXO
• Total Ports: 6 (2x FXS + 4x FXO)
• Form Factor: Single-wide NIM slot
• Compatible Routers: Cisco ISR 4221, 4321, 4331, 4351, 4431, 4451-X
• Minimum IOS: Cisco IOS XE 3.14.3 or later
• Replaces: VIC2-4FXO + VIC3-2FXS/DID (legacy ISR G2 cards)

Why Buy from Reef Telecom?

• ✅ 10-Year Warranty — the longest in the refurbished telecom industry
• ✅ Free Shipping on orders over $300
• ✅ Every unit professionally tested and inspected before shipping
• ✅ FedEx Priority and First Overnight shipping available

The Cisco NIM-2FXS/4FXO is the ideal voice module for businesses migrating from legacy analog infrastructure to VoIP while maintaining PSTN connectivity. Compatible with all Cisco 4000 Series ISR NIM slots, it provides a cost-effective upgrade path over the previous generation VIC2 and VIC3 cards.