Product Overview

Foxboro A2H124-24FX P0973BJ is a high-density managed fiber Ethernet switch engineered specifically for the Foxboro I/A Series Distributed Control System (DCS) architecture. Manufactured by Enterasys (now part of Extreme Networks), the P0973BJ designation is Foxboro‘s original material number confirming compatibility with the I/A Series platform. The core function of Foxboro A2H124-24FX P0973BJ is to provide a deterministic fiber-optic data backbone between distributed controllers, remote I/O, and supervisory systems in environments where electromagnetic interference is severe or transmission distance is constrained.

Within the actual network topology of a Foxboro DCS, Foxboro A2H124-24FX P0973BJ serves as a critical node for NodeBus communication. Field failure records confirm that this switch model has been deployed to connect engineer/operator stations with control stations via 24 optical channels, forming redundant A/B dual-bus structures . Foxboro A2H124-24FX P0973BJ is equipped with 24 × 100BASE-FX fiber ports using MT-RJ connectors, supplemented by two Gigabit SFP uplink slots and two 10/100/1000BASE-T RJ-45 ports, with stacking capability for up to eight units . As a managed Layer 2 switch, it supports VLAN, QoS, STP/RSTP, and port security features, meeting the dual demands of real-time performance and reliability required by process control networks.

 

Technical Specifications

Parameter Name	Parameter Value
Product Model	A2H124-24FX P0973BJ
Manufacturer	Enterasys (now Extreme Networks) / Foxboro branded
Product Type	Managed Fiber Ethernet Switch (Layer 2)
Fixed Fiber Ports	24 × 100BASE-FX, MT-RJ multimode
Uplink/Stacking Ports	2 × 10/100/1000BASE-T RJ-45; 2 × SFP (Mini-GBIC) slots
Switching Capacity	12.8 Gbps (standalone) / 102.4 Gbps (stacked)
Forwarding Rate	9.5 Mpps (standalone) / 76.2 Mpps (stacked)
Processor/Memory	MPC8241 266 MHz; DRAM 128 MB; Flash 16 MB
Dimensions	44.1 cm × 4.4 cm × 21.0 cm (1U rackmount)
Net Weight	Approximately 2.7 kg
Operating Temperature	0°C to 40–50°C (varies by source)
Power Input	100–240 VAC, 50–60 Hz
Redundant Power	Supports external C2RPS-SYS redundant power system
Stacking Capability	Up to 8 units, aggregate throughput up to 102.4 Gbps

 

Main Features and Advantages

Fiber-Intensive Connectivity for DCS Environments: The 24 × 100BASE-FX fiber ports of Foxboro A2H124-24FX P0973BJ represent its most distinctive design feature. In Foxboro I/A Series systems, these ports connect control stations and operator stations across the NodeBus. Fiber media inherently provides electrical isolation, effectively blocking ground loop currents and electromagnetic interference from degrading communication links. For refineries and chemical plants with numerous variable frequency drives and high-power equipment, this characteristic directly determines the long-term stability of DCS communications.

Dedicated Configuration Tool and System Integration: Deployment of this switch within Foxboro systems is not plug-and-play. Field practice confirms that before connecting optical ports, the dedicated SwitchConfigurator software must be used to complete system setup through a two-step process of configuration and download: selecting the P0973BJ model under A-Series Switches on a PC, building a configuration file, then connecting to the switch via serial port and executing the download . While this design raises the commissioning threshold, it ensures strict alignment between switch addresses and DCS network planning, reducing the risk of bus anomalies caused by configuration errors.

Redundancy Architecture Support: Foxboro A2H124-24FX P0973BJ supports connection to the Enterasys C2RPS-SYS redundant power system. When the internal power supply or external AC feed path fails, the redundant power source seamlessly assumes the full load without interrupting network traffic. In redundant bus configurations (such as A/B dual-path optical switches), this capability means a single switch power failure does not immediately degrade the bus, buying maintenance personnel a window for online replacement. Note that the switch does not support PoE, and connecting C2RPS-POE redundant power supplies is strictly prohibited as it may damage the equipment.