Moxa EDS-208A Series Switches

Technical Dossier

Product Details And Specifications

Moxa EDS-208A Series: Comprehensive Module Range and Technical Overview

The Moxa EDS-208A series represents one of the most widely deployed compact unmanaged Ethernet switch families in global heavy industry. Installed across petrochemical complexes, nuclear power plant auxiliary systems, offshore oil platforms, and continuous-process refineries, the EDS-208A line occupies a defined position in the Moxa industrial networking portfolio as a fixed-port, DIN-rail-mountable, unmanaged Layer 2 switch designed for deterministic Ethernet communication in electrically noisy environments.

The series operates across an extended temperature range (standard: 0°C to 60°C; wide-temp variants: -40°C to 75°C), supports 10/100 Mbps auto-negotiation on all copper ports, and is certified to IEC 61000-4 EMC standards — making it a reference-grade component for IEC 61511 functional safety architectures where network infrastructure must meet SIL-rated system requirements. Its passive cooling design (no fan) and conformal coating options make it suitable for Class I Division 2 / ATEX Zone 2 environments when installed in appropriate enclosures.

The EDS-208A series has accumulated significant installed base in Distributed Control System (DCS) network segments, particularly as a device-level switch connecting field instruments, remote I/O nodes, and HMI panels to supervisory Ethernet backbones. Its compatibility with Modbus TCP, PROFINET, and EtherNet/IP traffic (as a transparent Layer 2 device) has made it a default specification in engineering procurement construction (EPC) contractor bills of materials across Asia-Pacific, Middle East, and European process industries.

The Evolution of EDS-208A Architecture

The EDS-208A series is the second-generation evolution of Moxa's EDS-200 compact unmanaged switch family. The original EDS-205/EDS-208 (circa 2003–2006) established the physical form factor: DIN-rail mount, 5 or 8 port copper, 24 VDC input, screw-terminal power connector. These early units used 10/100 Mbps store-and-forward switching with a 1.6 Gbps switching fabric — adequate for the SCADA polling traffic of that era but without the surge protection and EMC hardening that process industry specifications increasingly demanded.

The EDS-208A revision (introduced approximately 2007–2009) addressed these gaps with the following architectural changes: (1) integrated 2 kV isolation on power input terminals, (2) upgraded ESD protection to IEC 61000-4-2 Level 4 on all RJ45 ports, (3) relay alarm output for power failure detection, and (4) dual power input support for redundant 12–48 VDC or 24 VAC supply architectures. The 'A' suffix specifically denotes the addition of the alarm relay contact — a critical differentiator for installations requiring network fault annunciation to plant DCS alarm systems.

Fiber-optic variants (EDS-208A-MM-SC, EDS-208A-SS-SC, EDS-208A-SS-SC-80) extended the series into long-distance and electrically isolated segment applications. Multi-mode fiber (MM) variants support up to 2 km at 100 Mbps; single-mode (SS) variants extend to 30 km; the SS-80 variant reaches 80 km — covering inter-building, inter-unit, and cross-site Ethernet runs in large refinery or power generation complexes.

By 2015, the EDS-208A series entered the mature/maintenance phase of its product lifecycle. Moxa's EDS-G308 and EDS-2008 series represent the current-generation successors, offering Gigabit uplinks and enhanced cybersecurity features (IEC 62443-4-2 alignment). However, the EDS-208A remains in active production for spare parts and replacement orders, and DriveKNMS maintains stock of both new and reconditioned units to support the large installed base that cannot be upgraded without full network redesign.

EDS-208A Full Catalog & Functionalities (SKU List)

The following SKUs represent the verified production models within the Moxa EDS-208A series. All models are 8-port unmanaged Fast Ethernet switches unless otherwise noted. Classification follows port media type and fiber reach.

Copper-Only Models (All-RJ45)

• EDS-208A: 8-port 10/100BaseT(X) unmanaged switch, dual 12–48 VDC / 24 VAC input, relay alarm output, DIN-rail mount.
• EDS-208A-T: Wide-temperature variant (-40 to 75°C) of the standard 8-port copper model; for outdoor cabinets and arctic-rated enclosures.

Multi-Mode Fiber Models (MM, up to 2 km)

• EDS-208A-MM-SC: 6×RJ45 + 2×100BaseFX multi-mode SC fiber ports; standard temperature.
• EDS-208A-MM-SC-T: Wide-temperature (-40 to 75°C) version of the MM-SC model.
• EDS-208A-MM-ST: 6×RJ45 + 2×100BaseFX multi-mode ST fiber ports; standard temperature.
• EDS-208A-MM-ST-T: Wide-temperature version of the MM-ST model.

Single-Mode Fiber Models (SS, up to 30 km)

• EDS-208A-SS-SC: 6×RJ45 + 2×100BaseFX single-mode SC fiber ports; 30 km reach; standard temperature.
• EDS-208A-SS-SC-T: Wide-temperature (-40 to 75°C) version of the SS-SC model.
• EDS-208A-SS-ST: 6×RJ45 + 2×100BaseFX single-mode ST fiber ports; 30 km reach; standard temperature.
• EDS-208A-SS-ST-T: Wide-temperature version of the SS-ST model.

Long-Haul Single-Mode Fiber Models (SS-80, up to 80 km)

• EDS-208A-SS-SC-80: 6×RJ45 + 2×100BaseFX single-mode SC fiber ports; 80 km reach; for cross-site or inter-facility Ethernet links.
• EDS-208A-SS-SC-80-T: Wide-temperature version of the 80 km SC model.

Mixed Copper + Fiber Combination Models

• EDS-205A: 5-port variant of the EDS-200A family; 3×RJ45 + 2×100BaseFX; frequently co-specified with EDS-208A in tiered network designs. (Note: same generation, same architecture, smaller port count.)
• EDS-205A-MM-SC: 5-port, multi-mode SC fiber version; standard temperature.
• EDS-205A-SS-SC: 5-port, single-mode SC fiber version; 30 km reach.
• EDS-205A-T: Wide-temperature 5-port copper-only variant.

Note: The EDS-208A series does not include managed switching, VLAN, QoS, or SNMP functionality. These features are available in the Moxa EDS-400A and EDS-500A managed switch families.

Sourcing Hard-to-Find & Obsolete EDS-208A Parts

Although Moxa continues to list the EDS-208A series as an active product, field procurement teams regularly encounter extended lead times (12–26 weeks) from authorized distribution channels, particularly for wide-temperature (T-suffix) and long-haul fiber (SS-80) variants. Plants operating under turnaround maintenance schedules or emergency corrective maintenance cannot absorb these lead times without production risk.

DriveKNMS maintains a dedicated inventory program for the EDS-208A series covering the following sourcing scenarios:

• New-in-box surplus stock: Units sourced from authorized distributor excess inventory, with original Moxa packaging and documentation. Batch traceability available on request.
• Reconditioned units: Factory-tested, firmware-verified units with full functional test reports. Supplied with 12-month DriveKNMS warranty.
• Emergency same-week dispatch: For critical plant shutdowns, DriveKNMS operates an expedited fulfillment channel with air freight to major industrial hubs (Rotterdam, Singapore, Houston, Jubail).
• Long-term supply agreements: For EPC contractors and plant operators managing multi-site EDS-208A installed bases, DriveKNMS offers blanket order arrangements with reserved stock allocation.

As the EDS-208A series approaches end-of-active-development status, DriveKNMS also provides migration consultation — mapping existing EDS-208A installations to compatible Moxa EDS-2008 or third-party equivalent platforms where full replacement is required.

Quality Control for the EDS-208A Range

All EDS-208A units processed through DriveKNMS undergo a structured inspection and functional test protocol before dispatch. The protocol is specific to the EDS-208A hardware architecture and covers the following test points:

• Power input verification: Dual power input terminals tested at 12 VDC, 24 VDC, and 48 VDC. Relay alarm output continuity verified under simulated power-fail condition on each input independently.
• Port-by-port link negotiation test: Each RJ45 port tested for 10/100 Mbps auto-negotiation, auto-MDI/MDI-X, and store-and-forward frame forwarding using a calibrated Ethernet test set. Frame loss at line rate measured and recorded.
• Fiber port optical power measurement: For MM and SS fiber variants, transmit optical power (dBm) and receive sensitivity are measured against Moxa published specifications. Fiber connectors (SC or ST) inspected under 200× magnification for end-face contamination or physical damage.
• EMC pre-screening: Units are powered in a controlled environment and subjected to conducted interference injection on power terminals per IEC 61000-4-4 (EFT/Burst) to verify surge protection circuit integrity.
• Thermal soak: Units operated continuously for 4 hours at 60°C ambient (standard temp models) or 75°C (T-suffix models) to screen for latent component failures.
• Firmware and label verification: Hardware revision and firmware version recorded. Serial number cross-referenced against Moxa production records where available.

Test records are retained for 3 years and are available to customers upon request for audit or regulatory compliance purposes.