NIM-2FXS/4FXO – 2-Port FXS + 4-Port FXO Voice Module – NIM
6/mo Solds
Established Global IT Distributor
With over a decade of industry experience, we are a certified Cisco Partner delivering genuine enterprise networking hardware and trusted services to system integrators, ISPs, and enterprises worldwide.
NIM-2FXS/4FXO Description
Cisco NIM-2FXS/4FXO is a hybrid analog voice Network Interface Module for Cisco ISR 4000 Series routers, offering two Foreign Exchange Station (FXS) ports and four Foreign Exchange Office (FXO) ports on a single card. The FXS ports can also function as Direct Inward Dial (DID) interfaces for inbound PSTN calls, while the FXO ports provide PSTN/PBX trunk connectivity with loop-start and ground-start signaling. With onboard DSP resources, the module supports up to 128-ms echo cancellation, comprehensive codec coverage, T.38 fax relay, and modem pass-through. It integrates seamlessly with Unified Communications protocols including SCCP, H.323, SIP, and MGCP, supports online insertion and removal (OIR), and is fully compatible with Cisco ISR 4300/4400 platforms running Cisco IOS XE software.
Key Features
Provides 2 FXS ports with DID capability plus 4 FXO ports, combining analog station support and PSTN trunk connectivity on one module.
Onboard DSP eliminates the need for router PVDMs, enabling time-division multiplexed voice, echo cancellation up to 128 ms, and consistent call quality.
Supports G.711, G.729a, G.726, plus G.723 and iSAC, ensuring flexible bandwidth optimization and interoperability across enterprise voice networks.
Offers caller-ID generation (FXS), detection (FXO), battery polarity reversal, Message Waiting Indicator (MWI), cable detection, and overload protection.
Delivers T.38 fax relay, fax pass-through, and modem pass-through for analog fax machines, POS systems, alarms, and dial-up devices in critical industries.
Supports OIR on ISR 4300/4400 routers, SNMP/MIB management, and interworks with SCCP, H.323, SIP, and MGCP 1.0 under Cisco IOS XE software.
Application Scenarios
Deploy both analog station lines and PSTN trunks on one router, ensuring smooth migration to VoIP while retaining legacy voice services.
Combine front-desk phones, guest-room analog lines, fax machines, and PSTN trunks in hotels and retail sites with unified management.
Maintain fax, modem, and analog phone connectivity while adding PSTN backup trunks for emergency services and regulatory compliance.
Product Comparison
|
Parameter |
NIM-2FXS/4FXO | ||
|---|---|---|---|
|
Port makeup |
2 × FXS (FXS/DID) |
4 × FXO |
2 × FXS (FXS/DID) + 4 × FXO |
|
DID capability |
Yes (inbound only) |
No |
Yes (FXS ports) |
|
MWI support |
Supported |
N/A |
Supported (FXS) |
|
Caller-ID / polarity |
Generation (FXS) |
Detection (FXO) |
Both (FXS generate, FXO detect) |
|
Signaling |
FXS, DID |
FXO loop/ground |
Both FXS and FXO |
|
Onboard DSP |
Yes |
Yes |
Yes |
|
Echo cancellation |
Up to 128 ms |
Up to 128 ms |
Up to 128 ms |
|
Codecs |
G.711/G.729a/G.726; G.723, iSAC |
Same |
Same |
|
Fax/modem |
T.38, pass-through |
Same |
Same |
|
Protocol interworking |
SCCP/H.323/SIP/MGCP |
Same |
Same |
|
OIR support |
Yes |
Yes |
Yes |
|
Minimum IOS XE |
3.13.4+ |
3.13.4+ |
3.14.3+ |
|
Weight |
0.42 lb (191 g) |
0.44 lb (200 g) |
0.52 lb (236 g) |
Specifications
| Parameter | Specification | Parameter | Specification |
|---|---|---|---|
| Model | NIM-2FXS/4FXO (2-port FXS + 4-port FXO Network Interface Module) | Form factor | NIM plug-in module for Cisco ISR 4000 Series |
| Ports | 2 × FXS and 4 × FXO, RJ-11 connectors | Interface type | Mixed Foreign Exchange Station (FXS) and Foreign Exchange Office (FXO) |
| Platform support | Cisco ISR 4321, 4331, 4351, 4431, 4451 | Online Insertion/Removal (OIR) | Supported |
| Typical devices connected (FXS) | Analog telephones, fax machines, modems, key systems | Typical devices connected (FXO) | PSTN lines, PBX trunks, analog CO connections |
| Signaling (FXS) | Loop start, Ground start | Signaling (FXO) | Loop start, Ground start |
| Ring voltage (FXS) | Up to 75 Vrms, 20–25 Hz | Loop current (FXS) | 20 mA to 30 mA nominal |
| Caller ID / Polarity reversal | Supported (Type I/II) | Battery reversal detection (FXO) | Supported |
| Voice codecs | G.711 (A/μ-law), G.729a/b, G.726, G.723.1 | Fax/Modem | T.38 Fax Relay, Fax/Modem passthrough |
| Protocol interworking | SIP, SCCP, H.323, MGCP 1.0 | RTP features | RTP/RTCP, RFC 4733 (DTMF relay) |
| Echo cancellation | Up to 128 ms tail length | Voice optimizations | VAD, CNG, cRTP (Compressed RTP) |
| DSP resources | On-module DSP (no chassis PVDM required) | Country configuration | Software-selectable (global homologation) |
| Cabling | 2-wire analog, straight-through RJ-11 | Use cases | Mixed analog device & PSTN connectivity in branch voice gateways |
| Minimum software | Cisco IOS XE 3.13 or later (UC license) | Management | CLI (console/SSH), SNMP, Cisco Prime Collaboration |
| Regulatory compliance | TIA-968-B (US), CS-03 (CA), AS/CA S002/S003 (AU), TBR 21 (EU) | Weight | Approx. 0.48 lb (≈220 g) |
| Power consumption | Under 12 W typical | Operating temperature | 0°C to 40°C (32°F to 104°F) |
| Ordering PID | NIM-2FXS/4FXO | Warranty | Per Cisco standard hardware warranty policy |
Get More Information
Need pricing, stock, or shipping details for the NIM-2FXS/4FXO ? Layer23-Switch can help you check current availability, lead time, and delivery options for this. Send us the part number, quantity, and destination country via live chat or email sales@layer23-switch.com for a fast quotation.
Quality Certifications
Customer Reviews
Questions & Answers
-
What does NIM-2FXS/4FXO provide?
-
When is NIM-2FXS/4FXO selected?
-
How are the FXS and FXO ports used on NIM-2FXS/4FXO?
-
Does NIM-2FXS/4FXO need external DSP modules?
-
What migration issue appears with NIM-2FXS/4FXO?
-
Which sites fit NIM-2FXS/4FXO?
-
What troubleshooting split matters for NIM-2FXS/4FXO?
-
What procurement check applies to NIM-2FXS/4FXO?
Warranty
Layer23-Switch.com offers genuine, high-quality ICT products at competitive wholesale prices—ensuring exceptional value without compromising quality.
All items are brand new, original, and factory-sealed.
Upon request, each unit can be fully tested and verified by a Cisco CCIE-certified engineer to ensure perfect working condition before shipment.
Our Cisco CCIE-certified experts provide free professional support via phone, email, online chat, or remote login—helping you deploy and troubleshoot with confidence.
If you are not satisfied with your purchase, you may request an exchange or full refund. Our customer service team will guide you through the return process quickly and smoothly. Visit Return Policy page for more information.
We support multiple secure payment and logistics options, backed by industry-leading verification:
Visit How to Pay page for more information
Extended, Worry-Free Warranty Coverage Factory New Sealed Enterprise Hardware:
· 3 Years Factory New Sealed
Visit Warranty Policy page for more information
Verify, plan, and comparewith confidence
Use practical tools to check device details, review lifecyclemilestones, and compare hardware before you buy.
Standard Services
Personalized Service, Superior Product Maintenance for Ultimate Satisfaction.
- Projects and Technical Support
- Easy Purchasing Supply
- Product Lifecycle Protection
- Exclusive F3 Team Support
Customized Support for Your Needs with CCIE, HCIE, HPE ASE, etc.
Asked about lead times. They were upfront and set accurate expectations.
Product was current, not old stock. Important to us.
Inspected by two team members independently. Both confirmed authenticity.
Service with honor. The goods are authentic.
Sales team helped confirm the part number. Very helpful.