Cisco PA-2T3+
2 Port T3 Serial Port Adapter Enhanced
Product Highlights
As WAN backbone demands grow and service providers need to provision DS3 connections at scale, managing external DSU equipment and disparate line termination hardware becomes a costly operational burden. The Cisco PA-2T3+ directly addresses this challenge.
The Cisco PA-2T3+ is a 2-Port T3 Serial Port Adapter Enhanced that delivers high-density, packet-over-DS3 connectivity for Cisco routing platforms. Each of its two independent T3 serial ports operates at full-duplex 44.736 Mbps, providing clear-channel DS3 line termination directly on the router. With integrated line interface unit / data service unit (DSU) functionality, the PA-2T3+ eliminates the need for external DSU hardware — simplifying DS3 line management, reducing provisioning costs, and freeing valuable rack space.
Designed as a single-width port adapter, the PA-2T3+ installs into a standard port adapter slot on the Cisco 7200 Series, Cisco 7200 VXR, Cisco 7500 Series, Cisco 7400 Series routers, the Cisco 7301, Cisco 7401ASR, and the Catalyst 6000 family FlexWAN module. It supports both 16-bit and 32-bit CRC error detection, SNMP-based management via MIB attributes, and compatibility with multiple third-party T3 DSU vendors. Whether you're building high-capacity corporate backbones, scaling Internet access trunks, or interconnecting service provider networks, the PA-2T3+ delivers reliable, manageable DS3 performance in a compact form factor.
Features & Benefits
Dual-Port DS3 Line Termination
The PA-2T3+ provides two independent T3 serial ports, each delivering full-duplex operation at the DS3 rate of 44.736 Mbps. This dual-port design doubles your WAN density per slot compared to single-port adapters, making it ideal for environments where port adapter slots are at a premium.
Integrated DSU Functionality
With built-in line interface unit and data service unit (DSU) capabilities, the PA-2T3+ allows DS3 lines to be terminated directly on the Cisco router. This eliminates the cost, rack space, and management overhead of standalone external DSU equipment, streamlining your WAN provisioning workflow.
Flexible Error Detection
The adapter supports both 16-bit and 32-bit cyclic redundancy checks (CRC), configurable via IOS command. The 32-bit CRC option provides stronger error detection for mission-critical links where data integrity is paramount.
SNMP-Based Management
MIB attributes are readable and writable via SNMP across the Integrated Local Management Interface (ILMI). This enables centralized, remote monitoring and configuration of your DS3 interfaces — reducing the need for on-site intervention and accelerating troubleshooting.
Broad Platform Support
The PA-2T3+ is compatible with a wide range of Cisco platforms including the 7200 Series, 7200 VXR, 7201, 7301, 7401ASR, 7304 (via PCI Port Adapter Carrier Card), 7000/7500 Series (via VIP), and Catalyst 6000 family (via FlexWAN module). This broad compatibility protects your investment across multiple deployment scenarios.
Deployment Scenarios
High-Capacity Corporate WAN Backbone
Organizations requiring high-bandwidth point-to-point WAN links between campus or data center sites can leverage the PA-2T3+'s dual DS3 ports to deliver up to ~90 Mbps of aggregate backbone capacity from a single slot. The integrated DSU simplifies provisioning and reduces equipment footprint at each site.
Service Provider DS3 Trunking
Internet service providers and managed network operators can use the PA-2T3+ to terminate clear-channel DS3 trunking connections on Cisco 7200 or 7500 Series routers. The high-density dual-port design and SNMP manageability support scalable, cost-effective service delivery.
Enterprise Internet Access Aggregation
Enterprises with high-speed Internet access requirements can terminate DS3 circuits from their carrier directly on the router, eliminating external DSU hardware. The PA-2T3+ provides a clean, manageable integration point for dual T3 uplinks with built-in redundancy potential.
General
Interfaces
Performance
Features
Physical
Compatibility
Compatibility Notes
Compatible Platforms
- Cisco 7200 Series Routers (including 7200 VXR)
- Cisco 7201 Router
- Cisco 7301 Router
- Cisco 7401ASR Router
- Cisco 7304 Router (via PCI Port Adapter Carrier Card)
- Cisco 7000 Series / 7500 Series Routers (via VIP — Versatile Interface Processor)
- Catalyst 6000 Family Switches (via FlexWAN module)
Cabling
- Requires 75-ohm coaxial cable (734A or equivalent) with BNC connectors
- Cisco coaxial cable part number: CAB-ATM-DS3/E3 (available in 10-foot / 3.05 m lengths)
Installation Notes
- Fits a single-width port adapter slot
- Up to one PA-2T3+ per port adapter slot; up to two per FlexWAN module or VIP
Downloads & Resources
Frequently Asked Questions
| Part Number | Product | Key Difference |
|---|---|---|
| PA-T3+ | Cisco 1-Port T3 Serial Port Adapter Enhanced | Single-port version — choose when only one DS3 interface is needed per slot to reduce cost. |
| PA-2T3/E3-EC | Cisco 2-Port Enhanced Capability Clear Channel T3/E3 Port Adapter | Successor with T3/E3 dual-mode support and lower CPU utilization (15%+ reduction). Recommended for new deployments. |
| PA-MC-2T3+ | Cisco 2-Port Multichannel T3 Port Adapter | Adds channelized T3 support (28 × T1 per T3) for environments requiring sub-T3 circuit provisioning. |
| PA-MC-2T3-EC | Cisco 2-Port Multichannel T3 Enhanced Capability Port Adapter | Enhanced multichannel version with lower CPU usage — ideal when both channelized and clear-channel T3 are needed. |