Cisco NM-4B-S/T Cisco network interface module
Brand: Cisco | Category: Accessories & Components
SKU: CSC-NM-4B-ST | Part #: NM-4B-S/T | MPN: NM-4B-S/T
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About the Cisco NM-4B-S/T Cisco network interface module
The Cisco NM-4B-S/T is a network interface module designed to expand ISDN connectivity on Cisco modular access routers, providing four dedicated WAN ports for organizations requiring integrated narrowband access across distributed sites. Network engineers and IT procurement teams seeking cost-effective ISDN integration for remote office connectivity, dial backup, or bandwidth-on-demand applications will find this module essential for extending the capabilities of their existing Cisco router infrastructure.
This genuine Cisco-manufactured module delivers four ISDN BRI S/T ports, each supporting the 2B+D channel structure (2 × 64 Kbps bearer channels plus 1 × 16 Kbps signaling channel) with a maximum bearer bandwidth of 128 Kbps per port. The module is compatible with Cisco 2600 series, 3600 series, and 3700 series modular access routers, enabling flexible deployment across multiple platforms. The NM-4B-S/T supports National ISDN-1, AT&T 5ESS, Nortel DMS-100, and Euro-ISDN (NET3/ETSI) switch types, making it suitable for both North American and European PSTN environments. An external NT1 is required for North American connections but not for native S/T bus operation in European deployments. All four ports use RJ-45 connectors and support industry-standard WAN protocols including PPP, Multilink PPP (MLP), HDLC, Frame Relay over ISDN, and X.25, while advanced routing features such as dial-on-demand routing (DDR), dial backup, and bandwidth-on-demand are managed through Cisco IOS Software and full CLI/SNMP capabilities.
Key Specifications
- Manufacturer Part Number: NM-4B-S/T
- Product Type: Network Module for Cisco modular access routers
- Number of WAN Ports: 4
- Interface Type: ISDN BRI S/T (4-wire S/T reference point)
- Channel Structure per Port: 2B+D (2 × 64 Kbps bearer + 1 × 16 Kbps signaling)
- Aggregate Bearer Bandwidth: Up to 512 Kbps
- Supported WAN Protocols: PPP, Multilink PPP (MLP), HDLC, Frame Relay over ISDN, X.25
For pricing, availability, and technical specifications tailored to your deployment requirements, contact Omnixon Global to submit a request for quote.
Technical Specifications
| Brand | Cisco |
| Category | Accessories & Components |
| SKU | CSC-NM-4B-ST |
| Part Number | NM-4B-S/T |
| Condition | New |
| Manufacturer Part Number | NM-4B-S/T |
| Product Type | Network Module |
| Form Factor | Network Module (NM) for Cisco modular access routers |
| Compatible Platforms | Cisco 2600 series, 3600 series, 3700 series modular access routers |
| Number of WAN Ports | 4 |
| Interface Type | ISDN BRI S/T (4-wire S/T reference point) |
| ISDN Channel Structure per Port | 2B+D (2 x 64 Kbps bearer + 1 x 16 Kbps signaling) |
| Bearer Channel Bandwidth per Port | 128 Kbps (both B-channels active) |
| Aggregate Bearer Bandwidth (all ports) | Up to 512 Kbps |
| Supported ISDN Switch Types | National ISDN-1, AT&T 5ESS, Nortel DMS-100, Euro-ISDN (NET3/ETSI) |
| NT1 Requirement | External NT1 required for North American PSTN connection; not required for native S/T bus (European) |
| Connector Type | RJ-45 |
| Supported WAN Protocols | PPP, Multilink PPP (MLP), HDLC, Frame Relay over ISDN, X.25 |
| Dial Features | Dial-on-demand routing (DDR), dial backup, bandwidth-on-demand |
| Management | Cisco IOS Software (host router); full IOS CLI and SNMP management |
| TAC Support Eligibility | Genuine Cisco hardware — eligible for Cisco TAC support validation |
| Hardware Authenticity | Genuine Cisco-manufactured module |
Frequently Asked Questions about Cisco NM-4B-S/T Cisco network interface module
What does the Cisco NM-4B-S/T Cisco network interface module do?
The Cisco NM-4B-S/T Cisco network interface module is enterprise IT hardware deployed in production data centers, server rooms, and edge sites across the GCC and EMEA region.