Cisco Single - Wide High Density Analog Voice Service Module with 8 FXS and 12 FXO

The Cisco Single-Wide High-Density Analog Voice Service Module is built for enterprises, managed services providers, and service providers who need a scalable, reliable way to bridge legacy analog telephony with modern IP networks. Designed for Cisco 4000 Series Integrated Services Routers (ISRs), this module packs 8 FXS ports and 12 FXO ports into a single-wide form factor, delivering dense telephony capacity without compromising space, power, or manageability. It enables direct connection to public-switched telephone networks (PSTNs) and to existing analog telephony equipment, making it ideal for expanding voice and fax capabilities at branch offices, contact centers, coexistence sites, and service-provider edge deployments. By consolidating voice and fax connectivity into one card, organizations can streamline their infrastructure, simplify administration, and accelerate migration to IP-based voice while preserving compatibility with legacy devices. This module also aligns with Cisco's robust reliability standards, ensuring consistent voice quality, predictable call performance, and smooth integration with Cisco IOS XE-based call routing, dial plan management, and security controls. Whether you are upgrading an existing installation or starting a new project that requires high-density analog interfaces, this module offers a reliable, scalable path to converge voice, fax, and PSTN access on the Cisco 4000 Series platform.

• Feature-rich, high-density voice interfaces: 8 FXS ports for connecting analog phones and fax devices plus 12 FXO ports for connecting to the PSTN, all in a single-wide module to maximize port density.
• Direct PSTN and analog-device integration: Seamlessly bridge legacy telephony with IP-based services, enabling hybrid deployments and gradual migration to SIP or IP-PBX environments.
• Enterprise-grade reliability and performance: Built to support consistent voice quality, reliable call handling, and secure operation within Cisco ISR ecosystems, with proven interoperability in complex networks.
• Ease of management and integration: native compatibility with Cisco IOS XE, enabling centralized configuration, monitoring, and QoS policies for voice traffic across remote locations and data centers.
• Future-proofed flexibility for fax and voice services: Supports traditional voice paths and fax transmissions, helping organizations preserve operations while transitioning to modern communications architectures.

Technical Details of Cisco Single - Wide High Density Analog Voice Service Module with 8 FXS and 12 FXO

Technical specifications are provided by the vendor and are designed to work with Cisco 4000 Series ISRs in a single-wide, high-density footprint. The module offers dedicated analog interfaces for both FXS (telephony devices) and FXO (PSTN access), enabling scalable voice and fax deployments in enterprise and service-provider networks. While exact SKU-specific values may vary by distributor and firmware release, the core capabilities remain consistent: robust analog voice support, seamless integration with Cisco IOS XE, and a compact form factor suitable for edge and data-center environments. This module is intended for use in supported Cisco chassis that provide a compatible backplane and power management for high-density, hot-swappable field-replaceable components. For consistent performance, ensure you deploy appropriate firmware and comply with Cisco hardware compatibility lists when planning upgrades or new installations.

• Form factor: Single-Wide high-density analog voice service module for Cisco 4000 Series ISRs
• Interfaces: 8 x FXS ports (analog handsets/fax devices) and 12 x FXO ports (PSTN access)
• Compatibility: Designed for Cisco 4000 Series Integrated Services Routers; integrates with Cisco IOS XE voice features
• Deployment model: Suitable for branch offices, data-center edge, and service-provider edge deployments needing dense analog connectivity
• Power and backplane: Power drawn from the ISR chassis backplane; relies on chassis provisioning and backplane signaling (no standalone supply required)

How to install Cisco Single - Wide High Density Analog Voice Service Module with 8 FXS and 12 FXO

To install this module, begin with a planned outage and ensure you have the appropriate chassis slot and firmware version for compatibility. Power down the Cisco ISR and disconnect all network interfaces to prevent damage during installation. Open the equipment enclosure and locate an available single-wide slot designated for voice service modules. Remove any filler or blanking plate from the slot, then carefully align the module’s edge connectors with the chassis backplane and slide the module into the slot until it seats firmly. Secure the module with the retention mechanism or screws per your chassis model, then reassemble the enclosure. Reconnect the power and allow the system to initialize; verify the module is detected in the hardware inventory through the IOS XE CLI or network management tool. Connect your analog devices to the FXS ports (telephones or fax machines) and connect your PSTN lines to the FXO ports. Configure voice ports, dial-peers, and any necessary voice routing on the ISR using the IOS XE CLI or a centralized management platform. Common tasks include class-of-service (CoS) and QoS policy application for voice traffic, enabling appropriate signaling (RTP, SIP considerations if a transiting gateway is used), and ensuring proper call admission control. Finally, perform end-to-end test calls, verify voice quality, confirm fax transmission if in use, and save the configuration to non-volatile memory. Maintain a record of the module’s serial number and firmware version for future support and updates. Ongoing administration should include regular health checks, port monitoring, firmware maintenance, and capacity planning to accommodate evolving telephony requirements.

Frequently asked questions

• What is the difference between FXS and FXO? FXS (Foreign Exchange Subscriber) provides the analog interface to connect a customer device like a telephone or fax, delivering dial tone, ring voltage, and power. FXO (Foreign Exchange Office) connects to the telephone network (PSTN) and receives those signals from the provider exchange. This module combines both interfaces to deliver a flexible analog voice solution.
• Is this module compatible with all Cisco 4000 Series ISRs? This module is designed for use with Cisco 4000 Series ISR platforms that support single-wide high-density analog modules. Compatibility depends on the specific ISR model, chassis backplane, and IOS XE software version—always verify the Cisco hardware compatibility list and firmware requirements for your exact setup.
• Can I use this module for fax over IP? The module supports traditional analog fax devices connected via FXS ports and can participate in fax workflows within a broader IP telephony environment. If you require fax over IP (T.38) fax relay, ensure your gateway and IP network configuration are compatible with your fax implementation strategy and the Cisco IOS XE capabilities in use.