Cisco SM-32A
32 port Asynchronous Module
Product Highlights
Managing dozens of remote network devices through individual console connections is time-consuming, error-prone, and operationally expensive. The Cisco SM-32A 32-Port Asynchronous Service Module solves this challenge by delivering high-density serial connectivity in a single-wide service module form factor designed for Cisco ISR G2 platforms.
The SM-32A provides 32 asynchronous EIA-232 serial ports, each capable of speeds up to 230.4 kbps, enabling centralized out-of-band management of routers, switches, servers, and other infrastructure devices across a TCP/IP network. Whether you're building a console server, deploying a dial access server, or aggregating low-speed WAN links, this module delivers the port density you need without consuming multiple module slots.
Designed for the Cisco 2900 and 3900/3900E Series ISR G2 routers, the SM-32A supports online insertion and removal (OIR) for non-disruptive maintenance and is fully managed through the Cisco IOS CLI or Cisco Configuration Professional (CCP). With a maximum power draw of just 15.72W and a compact single-wide footprint, it's an efficient, scalable solution for enterprise data centers, NOCs, and co-location facilities that require reliable serial access to large numbers of network devices.
Features & Benefits
High-Density Async Serial Connectivity
The SM-32A packs 32 asynchronous EIA-232 ports into a single-wide service module, significantly increasing async port density on Cisco ISR G2 platforms. On a Cisco 3900 series router, up to 192 async interfaces can be supported, enabling large-scale console server and terminal access deployments from a single chassis.
Out-of-Band Management
Asynchronous ports provide highly flexible connections that allow access to EIA-232 devices across a TCP/IP network. The SM-32A is commonly deployed to provide out-of-band connectivity to console or craft ports, allowing network operators to manage remote devices from a central location — critical for maintaining uptime when in-band management paths are unavailable.
Hot-Swap & Low Power Design
Online insertion and removal (OIR) is fully supported, allowing the SM-32A to be installed or replaced without powering down the router. With a maximum power consumption of just 15.72W, the module minimizes thermal impact and operating costs in dense deployments.
Cisco IOS Integration
The SM-32A is managed using existing Cisco IOS CLI commands and external management tools such as Cisco Configuration Professional (CCP). This means no new management paradigm to learn — your team can configure, monitor, and troubleshoot async ports using the same workflows they already know.
Deployment Scenarios
Enterprise Console Server / Terminal Server
Deploy the SM-32A in a Cisco ISR G2 router to create a centralized console server. Connect to the console ports of routers, switches, firewalls, and servers via octal breakout cables, enabling remote Telnet/SSH access to each device's console through a single management platform.
Network Operations Center (NOC) Out-of-Band Management
In NOC and data center environments, the SM-32A provides a dedicated out-of-band management path to critical infrastructure. When primary network connectivity fails, operators can still reach device consoles through the async serial connections, ensuring rapid troubleshooting and recovery.
WAN Aggregation & Legacy Protocol Transport
Organizations with legacy serial devices — such as industrial controllers, SCADA equipment, or older WAN links — can use the SM-32A to aggregate low-speed asynchronous connections into a modern Cisco ISR G2 router, bridging legacy infrastructure with current IP networks.
General
Interfaces & Performance
Physical
Power
Environmental
Features
Platform Compatibility
Compliance
Compatibility Notes
Platform Compatibility
The SM-32A is supported in the service module (SM) slots of the following Cisco ISR G2 routers:
| ISR G2 Series | Supported Models | Minimum IOS Release |
|---|---|---|
| 2900 Series | 2911, 2921, 2951 | 15.1(4)M3 |
| 3900 Series | 3925, 3945 | 15.1(4)M2; 15.2(1)T1; 15.2(2)T |
| 3900E Series | 3925E, 3945E | 15.1(4)M2; 15.2(1)T1; 15.2(2)T |
Not supported on Cisco 1800, 2800, or 3800 Series routers.
Cabling Requirements
The SM-32A uses high-density 8-port connectors. Octal breakout cables are required to connect to end devices:
- CAB-OCTAL-ASYNC= — 8-port async cable (RJ-45 ends) for console/terminal connections
- CAB-OCTAL-MODEM= — 8-port modem cable for modem connections
RJ-45-to-DB-25 modular adapters can be used to convert RJ-45 to DB-25 DTE or DCE connections.
Downloads & Resources
Frequently Asked Questions
| Part Number | Product | Key Difference |
|---|---|---|
| HWIC-16A | Cisco 16-Port Async HWIC | 16 async ports in an HWIC form factor; fits HWIC/EHWIC slots and supports broader platform range including 1800/2800/3800 series |
| HWIC-8A | Cisco 8-Port Async HWIC | 8 async EIA-232 ports in a compact single-wide HWIC; ideal for lower-density requirements or platforms without SM slots |
| HWIC-8A/S-232 | Cisco 8-Port Async/Sync HWIC | 8 ports with both synchronous (up to 256 kbps) and asynchronous support; choose this when sync serial capability is required |
| HWIC-4A/S | Cisco 4-Port Async/Sync HWIC | 4 ports supporting async and sync serial with EIA-232/449/530 and V.35; best for mixed-protocol, low-density WAN needs |