Cisco HWIC-ADSLI-B/ST
2-port HWIC w/ 1-port ADSLoISDN and 1-port ISDN BRI-S/T
Product Highlights
Branch offices and remote sites that rely on DSL-based WAN links need a reliable, cost-effective way to maintain connectivity — especially when fiber or MPLS is unavailable. The Cisco HWIC-ADSLI-B/ST is a 2-port High-Speed WAN Interface Card that combines one ADSL over ISDN (ADSLoISDN) port with one data-only ISDN BRI S/T backup port on a single, compact module.
The ADSLoISDN port supports ADSL, ADSL2, and ADSL2+ standards, delivering downstream speeds up to 24 Mbps and upstream speeds up to 1.5 Mbps over an existing ISDN line. When the primary ADSL link fails, the integrated ISDN BRI S/T port provides automatic data-only failover at 64 Kbps per B-channel, keeping critical applications online while the primary circuit recovers.
Designed for Cisco Integrated Services Routers — including the 1841, 1861, 2800, 3800, 1900, 2900, and 3900 Series — the HWIC-ADSLI-B/ST fits into any HWIC-enabled slot and is fully managed through Cisco IOS Software. This makes it an ideal WAN module for branch offices, retail locations, and remote sites that need resilient broadband connectivity with built-in redundancy, all without adding a separate failover device to the rack.
Features & Benefits
ADSL2+ Broadband WAN Connectivity
The ADSLoISDN port supports ADSL, ADSL2, and ADSL2+ standards with downstream rates up to 24 Mbps and upstream rates up to 1.5 Mbps. This enables branch offices to leverage existing ISDN telephone infrastructure for high-speed broadband access without requiring a dedicated POTS line.
Integrated ISDN BRI-S/T Backup
The second port provides a data-only ISDN BRI S/T connection with two 64 Kbps B-channels. When the primary ADSL link goes down, the ISDN BRI port can serve as an automatic failover path, ensuring business-critical traffic continues to flow and minimizing costly downtime.
Compact Single-Wide HWIC Design
Packaged in the Cisco standard single-wide HWIC form factor, this module occupies just one HWIC slot and draws power directly from the host router — no external power supply needed. This preserves slot density for other interface cards and simplifies deployment.
Broad Cisco ISR Platform Support
The HWIC-ADSLI-B/ST is supported on a wide range of Cisco ISR platforms including the 1841, 1861, 2801, 2811, 2821, 2851, 3825, 3845, 1941, 2901, 2911, 2921, 2951, 3925, and 3945. This broad compatibility makes it easy to standardize on a single WAN module across diverse router deployments.
Cisco IOS Software Management
Fully managed through Cisco IOS Software, the HWIC-ADSLI-B/ST supports CLI configuration, SNMP monitoring, and advanced features such as QoS, security policies, and differentiated classes of service. This enables service providers and enterprises to deliver managed, business-class DSL services.
Deployment Scenarios
Branch Office Primary WAN with ISDN Failover
Deploy the HWIC-ADSLI-B/ST in a Cisco ISR at a remote branch office to terminate an ADSL over ISDN circuit as the primary WAN link. The integrated ISDN BRI-S/T port provides automatic data-only backup, ensuring continuous connectivity for ERP, email, and VPN traffic even during ADSL outages.
Retail or Point-of-Sale Location Connectivity
Retail stores and kiosks in areas without fiber can use the HWIC-ADSLI-B/ST to establish broadband WAN access over existing ISDN infrastructure. The built-in failover port protects transaction processing and inventory systems from link failures without requiring additional hardware.
Service Provider Managed CPE Deployment
Service providers deploying managed Cisco ISR routers at customer premises can use the HWIC-ADSLI-B/ST to deliver business-class ADSL services with ISDN backup. Cisco IOS features like QoS, security, and CoS enable differentiated service tiers and remote management from a central NOC.
General
Interfaces & Ports
Performance
Protocols & Standards
Indicators
Environmental
Power
Software Compatibility
Compatibility Notes
Compatible Cisco ISR Platforms
- ISR G1: Cisco 1841, 1861, 2801, 2811, 2821, 2851, 3825, 3845
- ISR G2: Cisco 1921, 1941, 2901, 2911, 2921, 2951, 3925, 3925E, 3945, 3945E
Minimum Cisco IOS Requirements
- ISR G1 (1841, 1861, 2800, 3800): Cisco IOS Software Release 12.4(6)T or later (2-port HWICs)
- ISR G2 (1900, 2900, 3900): Cisco IOS Software Release 15.0(1)M or later
Slot Requirements
The HWIC-ADSLI-B/ST must be installed in an HWIC-enabled interface slot. Consult the Overview of Cisco Interface Cards for Cisco Access Routers document to verify which slots in your specific router model accept HWICs.
Downloads & Resources
Frequently Asked Questions
| Part Number | Product | Key Difference |
|---|---|---|
| HWIC-ADSL-B/ST | Cisco ADSL over POTS + ISDN BRI-S/T HWIC | Uses ADSL over POTS (Annex A) instead of ADSL over ISDN (Annex B) — choose based on your local telco line type. |
| HWIC-1ADSLI | Cisco 1-Port ADSL over ISDN HWIC | Single-port ADSLoISDN only — no integrated ISDN BRI backup port. Lower cost when failover is not required. |
| HWIC-2SHDSL | Cisco 2-Port G.SHDSL HWIC | Provides symmetric DSL (G.SHDSL) instead of asymmetric ADSL — suited for applications requiring equal upstream and downstream bandwidth. |