Product Core Brief

• Model: A4H124-24FX (Manufacture Part Number P0973JN)
• Brand: Enterasys (Acquired by Extreme Networks)
• Series: A4 Stackable Industrial/Enterprise Managed Switch Series
• Core Function: Layer 2/3 stackable managed switch equipped with 24 SC multimode 100BASE-FX fiber ports, designed for long-distance EMC-hardened industrial control, SCADA and DCS network deployments
• Product Type: All-Fast Ethernet Fiber Managed Stackable Network Switch
• Key Specs: 24×100BASE-FX SC multimode | 2×10/100/1000BASE-T RJ45 stack/uplink | 2×SFP Gigabit expansion slots | 8K MAC table | IEEE STP/RSTP/LACP supportNote: Fully discontinued end-of-life network hardware, stocked exclusively as unopened tested New Surplus inventory; P0973JN is the unique factory part identifier for this fiber-only variantManualsLib.

Key Technical Specifications

• Port Layout:
  • 24 × 100BASE-FX SC multimode fiber ports (2km max transmission distance)
  • 2 × 10/100/1000BASE-T copper RJ45 stacking/uplink ports
  • 2 × SFP gigabit modular uplink expansion slots
  • DB9 RS232 local console port for out-of-band management
• Switching Performance:
  • Switching fabric capacity: 8.8 Gbps non-blocking
  • Packet forwarding rate: 6.5 Mpps (64-byte frames)
  • MAC address table: 8,192 address entries
  • Jumbo frame support up to 9216 bytes
• Supported Standard Protocols:IEEE 802.1Q VLAN (255 maximum VLANs), 802.1p QoS, 802.3ad LACP link aggregation, 802.1D STP, 802.1w RSTP, 802.1x port security, IGMP Snooping v1/v2/v3, SNMPv1/v2c/v3, RMON, SSH/HTTPS/Telnet management
• Power & Electrical:Input: 100–240VAC 50/60Hz universal internal power supplyMax power draw: 65.7W, rated input current 1.0AExternal redundant power supply (RPS) dedicated expansion header
• Environmental Ratings:Operating cabinet temperature: 0°C ~ +50°C continuous; storage -40°C ~ +70°CHumidity: 5%–95% non-condensingEMC Class A industrial compliance, heavy EMI suppression for DCS/SCADA cabinet environments
• Mechanical Dimensions & Weight:440mm W × 44mm H × 365mm D (1U standard rack-mount form factor)Unit weight: 4.85kg (10.7 lb)ManualsLib
• Physical & Certification:19-inch rack-mount brackets pre-installedFCC Class A, CE, UL safety certificationsConformal coated main PCB for corrosive industrial cabinet atmospheres

Product Introduction

This all-fiber managed stackable switch eliminates copper cable ground loop interference common in refinery, power plant and offshore DCS control networks. The 24 dedicated multimode fiber ports extend fast Ethernet communication up to 2 kilometers without signal repeaters, ideal for distributed field I/O racks and remote SCADA equipment.Built-in stacking via dual gigabit RJ45 ports allows multiple A4-series switches to operate as a single unified management domain, while modular SFP uplink slots provide flexible long-haul single-mode fiber or copper backbone connectivity. Hardware QoS traffic prioritization ensures critical process control telemetry takes priority over auxiliary non-critical network traffic during congestion events.

QA & Testing SOP (Transparency Building)

1. Incoming Inspection: Cross-reference P0973JN factory part label against OEM batch production logs; inspect SC fiber transceiver ports for scratched lenses, bent RJ45 pins, cracked chassis and damaged console port; verify original factory anti-static foam packaging seal integrity.
2. Live Bench Testing: Install unit on industrial test rack powered by calibrated AC supply; populate all 24 FX fiber ports with loopback transceivers, run 24-hour continuous traffic generation, full VLAN/STP/LACP configuration validation and stack link failover simulation.
3. Electrical & Optical Testing: Verify all fiber ports meet OEM optical transmit/receive power tolerances via fiber power meter; confirm AC power supply voltage stability across full input range, test console port serial communication and SFP slot hot-detect functionality.
4. Firmware & Config Backup: Capture factory default OS firmware version, export baseline running-config and document console port baud rate settings for field service reference before bench validation.
5. Final QC Packaging: Attach serialized printed test pass tag listing optical port test results; seal unit in foam-lined anti-static bag to protect fiber transceivers and metal chassis during warehouse storage and transit.

Installation Pitfalls & Field Deployment Guide

❗ Firmware Rev Compatibility Risk: Older A4-series firmware v4.x lacks full RSTP fast failover and industrial QoS queue scheduling; upgrade switch OS to v5.2 or newer before rack deployment to avoid unplanned control network communication drops during fiber link faults.❗ Stack Cable Configuration Loss: Photograph stacking RJ45 cable port mapping on the existing switch before replacement; miswired stacking links split the switch fabric into isolated unmanaged domains and break cross-switch VLAN forwarding.❗ Fiber Wiring Incompatibility: This model uses SC multimode fixed transceivers; direct substitution with single-mode fiber cabling without mode conditioning patch cords creates severe signal attenuation and intermittent port flapping.❗ Bandwidth Miscalculation: Populating all 24 FX ports with high-frequency process HART/SCADA telemetry can saturate a single gigabit uplink; deploy dual LACP aggregated uplinks for full traffic load balancing.❗ ESD Optical Damage Risk: Ungrounded technicians handling exposed SC fiber transceivers discharge static into internal photodiode circuits; latent damage creates slow, progressive port signal degradation that surfaces after 3–4 weeks of continuous runtime.

4-step replacement deployment guide:

1. Pre-install LOTO: Disconnect cabinet AC power supply; attach grounded anti-static wrist strap to rack ground bus bar, disconnect all active fiber patch cords and stacking uplink cables from the old switch unit.
2. Removal: Document stacking port cable layout via photo; extract all fiber patch cords channel by channel, unfasten 1U rack mounting screws and slide the legacy unit fully out of the equipment rack.
3. Hardware Install: Secure new A4H124-24FX P0973JN into 1U rack slot; replicate stacking cable mapping from reference photos, reterminate all fiber patch cords to matching SC port numbers, insert approved gigabit SFP transceivers into uplink expansion slots as required.
4. Power-on Validation: Restore rack AC power; connect laptop via DB9 console port, verify all fiber ports show steady link-up LED status, confirm stack topology syncs correctly and run VLAN/STP fault injection tests to validate redundant network failover behavior.

FAQ

Q: Can multiple A4H124-24FX units be stacked together for unified DCS network management?A: Yes. The dual rear-panel 10/100/1000BASE-T RJ45 ports are dedicated stacking interfaces, supporting up to 8 A4-series switches in a single logical stack domain with shared single-point SNMP/console management. Mixed copper A4 variants (A4H124-24) can be stacked alongside this all-fiber model without protocol incompatibility.Q: Does this switch support hot-swapping of SFP uplink transceivers while powered?A: SFP expansion slots support hot insertion/removal without full switch power shutdown, but all active fiber and stacking copper links should be isolated during transceiver replacement to avoid temporary network broadcast storms.Q: What warranty coverage applies to bench-tested surplus P0973JN units?A: All stocked inventory carries a 12-month functional warranty covering internal power supply, fiber transceiver modules, switching ASIC and PCB circuit defects. Damage from scratched fiber lenses, ungrounded ESD handling, incorrect single-mode fiber cabling or AC power surge overload is excluded from coverage terms.Q: Is there a direct drop-in modern replacement for this discontinued all-fiber switch?A: Extreme Networks current industrial fiber switch lines offer equivalent 24-port fast fiber capacity, but full fiber patch cord retermination and complete DCS network VLAN/STP configuration revalidation is mandatory; stacking protocol timing and SC port mechanical footprint do not support unmodified direct rack swap.Q: What maximum transmission distance does the onboard 100BASE-FX multimode SC transceiver support?A: OEM rated maximum reach is 2000 meters using standard 62.5/125μm multimode fiber cable at 1310nm wavelength; distance reduces to 1km with 50/125μm multimode cabling.Q: Can this switch run critical SIL-rated process control SCADA traffic?A: Hardware QoS 802.1p priority queuing and RSTP sub-500ms link failover meet standard industrial control network requirements; for full SIL2/SIL3 network fault tolerance the deployment requires redundant dual independent switch fabrics with physically separated fiber cable routes.Q: Can standard CAT6 copper patch cords be used for the dedicated stacking ports?A: Category 5e or higher copper patch cables are fully supported for stacking inter-switch links; cable length limited to 100m maximum per IEEE 802.3 gigabit copper specifications.