NIM-4FXSP – 4-Port FXS Voice – P-Version Analog NIM – Cisco ISR
Why Layer23-Switch
Stocked, Shipped and Supported by One Team
Ships in 1 Business Day
In-stock orders leave our Hong Kong or U.S. warehouse within 1 business day after payment, with tracking by email.
LSCare Warranty
3years on enterprise equipment
Free CCIE Support
Certified engineers help before and after you buy. Reply within 1 business day by email or live chat.
Verify Before You Pay
100%factory-sealed
Get label and serial photos before shipment, and check every serial number with Cisco.
NIM-4FXSP Description
The NIM-4FXSP is a Cisco 4000 Series ISR analog voice network interface module in the P hardware revision, for branch routers that connect phones, fax machines and key systems. The module has four FXS/FXS-E/DID-capable voice ports and onboard DSP, with the same functions as the non-P hardware. The module needs Cisco IOS XE 16.5 or later, because on earlier releases it boots but its analog voice ports do not show up in the voice port summary.
Quick Specs
|
Parameter |
Specification |
|---|---|
|
Product ID |
NIM-4FXSP |
|
Product type |
4-port FXS analog voice Network Interface Module |
|
Cisco ordering description |
4-Port Network Interface Module – FXS, FXS-E and DID |
|
Total ports |
4 FXS/FXS-E/DID-capable voice ports |
|
P-version note |
New manufacturing component version; no functionality change from the non-P version |
|
Analog interface role |
Station-side FXS service or DID incoming-call service |
|
ISR G2 comparison |
VIC3-4FXS/DID |
|
Supported router context |
Cisco 4000 Series ISR NIM slots; Cisco 4300 and 4400 Series support context |
|
Cisco IOS XE release for this SKU |
XE16.5 and above |
|
Voice package requirement |
Minimum Unified Communications technology package for voice applications |
|
DSP design |
Onboard DSP on the voice NIM; no dedicated motherboard PVDM required for this voice module family |
|
OIR support |
Supported in Cisco 4000 Series ISR NIM slots; managed OIR requires no active calls |
Application Scenarios
A branch router running Cisco IOS XE 16.5 or later can connect analog phones, fax machines and key systems to the four FXS ports on the module.
An office that gets DID numbers from the central office can land them on the DID-capable ports for incoming calls, and DID mode does not support caller ID.
Product Comparison
|
Parameter |
NIM-4FXSP |
NIM-2FXS/4FXOP | ||
|---|---|---|---|---|
|
Voice ports |
4 FXS/FXS-E/DID-capable |
4 FXS/FXS-E/DID-capable |
2 FXS/FXS-E/DID-capable |
2 FXS/FXS-E/DID-capable and 4 FXO |
|
Port function |
Station-side FXS or DID incoming-call service |
Station-side FXS or DID incoming-call service |
Station-side FXS or DID incoming-call service |
Station-side FXS or DID plus line-side FXO |
|
Supported platforms |
Cisco 4300 and 4400 Series ISRs |
Cisco 4300 and 4400 Series ISRs |
Cisco 4300 and 4400 Series ISRs |
Cisco 4300 and 4400 Series ISRs |
|
Unsupported platforms |
Cisco 2900 and 3900 Series ISRs |
Cisco 2900 and 3900 Series ISRs |
Cisco 2900 and 3900 Series ISRs |
Cisco 2900 and 3900 Series ISRs |
|
Cisco IOS XE release |
XE16.5 and above |
XE3.13.4, XE3.14.3, XE3.15.1, XE3.16 and above |
XE16.5 and above |
XE16.5 and above |
NIM-4FXSP and NIM-4FXS have the same four FXS/FXS-E/DID-capable ports and the same Cisco ordering description, but the P hardware revision needs IOS XE 16.5 or later, whereas NIM-4FXS also runs on 3.13.4, 3.14.3, 3.15.1 and 3.16. Routers that cannot move to XE 16.5 therefore take NIM-4FXS, since the P module on an earlier release boots without showing its analog voice ports. Two station lines call for NIM-2FXSP, which has two FXS/FXS-E/DID-capable ports on the same P revision. Where FXS stations and FXO trunks share one slot, NIM-2FXS/4FXOP adds four FXO ports to two FXS-class ports.
Ordering Checklist
- Router hosts: Order for Cisco 4300 and 4400 Series ISR NIM slots. NIM-4FXSP installs only in a 4000 Series ISR NIM slot, so 2900 and 3900 Series routers cannot take it.
- SM-X slots: Add a NIM carrier card when the host uses an SM-X slot; it converts the slot to a NIM slot for one single-wide or double-wide NIM. Without it, NIM-4FXSP cannot be installed.
Specifications
| Parameter | Specification | Parameter | Specification |
|---|---|---|---|
| Product ID | NIM-4FXSP | Product type | FXS analog voice Network Interface Module |
| Cisco ordering description | 4-Port Network Interface Module – FXS, FXS-E and DID | Total ports | 4 FXS/FXS-E/DID-capable voice ports |
| P-version note | Created due to a new hardware component in manufacturing | Functional relationship | No functionality change from the non-P version |
| Analog interface role | Station-side FXS service or DID incoming-call service | ISR G2 comparison | VIC3-4FXS/DID |
| Supported router family | Cisco 4000 Series Integrated Services Routers | Documented ISR series context | Cisco 4300 and 4400 Series ISRs |
| Unsupported ISR family | Not supported with Cisco 2900 and 3900 Series ISRs | Cisco IOS XE release for this SKU | XE16.5 and above |
| Voice package requirement | Minimum Unified Communications technology package for voice applications | DSP design | Onboard DSP on the voice NIM family |
| Motherboard PVDM requirement | No dedicated packet voice DSP module required on the router motherboard for this voice NIM family | FXS endpoint connection role | Direct connection to phones, fax machines, and key systems |
| DID connection role | Off-premises DID connection from the central office for incoming PSTN calls | DID caller ID note | DID mode does not support caller ID |
| FXS feature notes | FXS or DID functionality, configurable long loop ports, message waiting indicator, and cable detection | FXS signaling options | did delay-dial, did immediate, did loopStart, groundStart, or loopStart |
| Ring frequency options | 20, 25, 30, or 50 Hz | Call progress tone setting | cptone locale under voice-port configuration |
| Voice-port configuration form | voice-port slot/subunit/subslot | Managed OIR restriction | Managed OIR is not supported with active calls |
| OIR support | FXS, FXO, E/M, and BRI NIMs can be inserted into supported Cisco 4000 Series ISR NIM slots without powering off the router | Cabling note | Straight-through 2-wire cable for NIM FXS and FXO port connections |
| Analog NIM jumper note | No jumpers to set on NIM analog modules | Network management | Remote and local configuration, monitoring, and troubleshooting from Cisco IOS XE Software CLI |
Quality Certifications
Customer Reviews
Questions & Answers
-
Which routers and slots can host NIM-4FXSP?
-
Which Cisco IOS XE release does NIM-4FXSP need?
-
Is NIM-4FXSP supported as an analog voice option on the Catalyst 8300?
-
Does NIM-4FXSP support the clock-participate command?
-
Which ring frequencies can NIM-4FXSP use on its FXS ports?
-
Does caller ID work on NIM-4FXSP when a port runs in DID mode?
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.

Great value for the money. Highly recommended.
Layer23 doesn’t just take your order and disappear. They stay involved.
Our long-term plan includes Layer23 as a key supply partner.
Solid packing! You could drop a rock on it and it would be fine.
We rely on you for these components. Always reliable.