EM-HDA-3FXS/4FXO Cisco 7-Port Voice/Fax Expansion Module - 3FXS/4FXO
Cisco EM-HDA-3FXS/4FXO 7-Port Voice/Fax Expansion Module
High-Density Analog Voice Integration for Integrated Services Routers
The Cisco EM-HDA-3FXS/4FXO is a high-density analog voice expansion module designed to enhance the voice connectivity capabilities of Cisco Integrated Services Routers (ISR). This versatile module provides a balanced combination of 3 FXS (Foreign Exchange Station) ports and 4 FXO (Foreign Exchange Office) ports, enabling organizations to connect analog devices such as phones, fax machines, and modems, while also supporting direct connections to the Public Switched Telephone Network (PSTN) or legacy PBX systems.
Engineered for scalable voice deployments, the EM-HDA-3FXS/4FXO module integrates with the Cisco EVM-HD-8FXS/DID High-Density Voice Network Module, allowing businesses to expand analog voice capacity without consuming additional router slots. This high-density architecture helps optimize hardware utilization while supporting growing voice infrastructure requirements.
The module supports Loop Start and Ground Start signaling for both FXS and FXO interfaces, ensuring compatibility with a wide range of telephony systems. With Caller ID support, hardware-based echo cancellation, and REN support of up to 5 per port, it delivers reliable voice quality and stable analog connectivity. Additionally, the module is designed to support fax and modem transmissions using T.38 fax relay or bypass modes, making it suitable for organizations that rely on legacy fax communications within modern IP networks.
For enhanced reliability, the FXO ports can provide emergency PSTN connectivity during power failures or network outages, helping maintain essential communication services. Fully integrated with Cisco IOS software, the module supports advanced voice features such as dial-peer configuration, call routing, PLAR, and call hunting, enabling flexible voice management and deployment.
Ideal for enterprise branch offices, VoIP gateways, and hybrid telephony environments, the Cisco EM-HDA-3FXS/4FXO voice expansion module provides a reliable and scalable solution for integrating traditional analog devices into modern IP-based communication networks.
Product Specifications – Cisco EM-HDA-3FXS/4FXO High-Density Analog Voice Expansion Module
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| Specification | Details |
|---|---|
| Manufacturer | Cisco Systems |
| Product Model | Cisco EM-HDA-3FXS/4FXO |
| Part Number | EM-HDA-3FXS/4FXO |
| Module Type | High-Density Analog Voice Expansion Module |
| Total Ports | 7 Analog Voice Ports |
| FXS Ports | 3 Ports (Foreign Exchange Station) |
| FXO Ports | 4 Ports (Foreign Exchange Office) |
| Connector Type | RJ-11 Compatible via Breakout Cable |
| FXS Signaling Support | Loop Start, Ground Start |
| FXO Signaling Support | Loop Start, Ground Start |
| REN (Ringer Equivalence Number) | Up to 5 per port |
| Caller ID Support | Supported on both FXS and FXO ports |
| Echo Cancellation | Hardware-based echo cancellation via DSP on base module |
| Fax Support | T.38 Fax Relay and Pass-through |
| Modem Support | Supported |
| Emergency Calling Support | PSTN fallback through FXO ports |
| Interface Type | Expansion module for High-Density Voice Network Module |
| Compatible Base Module | Cisco EVM-HD-8FXS/DID |
| Router Compatibility | Supported Cisco Integrated Services Routers (ISR) |
| Management | Managed through Cisco IOS Software |
| Voice Features Support | Dial-peers, PLAR, call hunting, digit manipulation |
| Deployment Environment | Enterprise branch offices, VoIP gateways |
| Typical Use Cases | Analog phone connectivity, fax integration, PSTN trunking, VoIP migration |
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FAQs:
Q1. Does this module plug directly into the router's NIM or SM-X slot?
No. The EM-HDA-3FXS/4FXO is a daughter card. It must be installed onto a base module, specifically the EVM-HD-8FXS/DID, which then slides into the router's Network Module (NM) or SM-X slot.
Q2. What is the difference between FXS and FXO ports?
FXS (Station) ports connect directly to analog end-devices like phones or faxes (they provide dial tone and battery). FXO (Office) ports connect to the telephone company's wall jack or a PBX (they receive dial tone).
Q3. Does this module require Digital Signal Processors (DSPs)?
Yes. Voice traffic must be digitized. The DSPs are typically located on the router's motherboard (PVDM modules) or on the base network module.
Q4. Which routers are compatible with this module?
This module is primarily used with the Cisco 2800, 2900, 3800, and 3900 series ISRs. Compatibility with newer ISR 4000 series requires the use of a legacy SM-X carrier module.
Q5. How do I connect the cables to these ports?
Because the module is compact, it often uses a high-density connector. You will typically need a breakout cable (such as a CAB-500-RJ11 or similar) to convert the module's interface into standard RJ-11 jacks.
