Moxa EDS-208A Modules

Technical Dossier

Product Details And Specifications

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

The Moxa EDS-208A is a compact, unmanaged industrial Ethernet switch belonging to the EDS-200 product family. It is engineered for deployment in space-constrained industrial environments where deterministic network connectivity is required without the overhead of managed switch configuration. The EDS-208A series has accumulated significant installed base across global heavy industries including petrochemical refineries, nuclear power auxiliary systems, offshore oil & gas platforms, pulp and paper mills, and continuous-process chemical plants.

Its DIN-rail form factor, wide operating temperature range (−10°C to 60°C standard; −40°C to 75°C for T-grade variants), and redundant power input design make it a standard-specification component in IEC 61850 substation automation panels and ISA-99 segmented control networks. The switch operates at wire speed across all 8 Fast Ethernet ports with a non-blocking switching fabric, making it suitable for time-sensitive SCADA polling cycles and Modbus TCP/IP traffic.

In global DCS and PLC infrastructure, the EDS-208A is frequently found as the edge-layer switch connecting field devices (RTUs, I/O modules, drives) to the plant LAN backbone. Its passive cooling design eliminates fan-related MTBF degradation, a critical factor in 24/7 continuous-operation facilities.

The Evolution of EDS-208A Architecture

The EDS-208A was introduced as a successor to the original EDS-208 platform, incorporating hardware-level improvements to the power input circuitry and expanding the operating temperature envelope for harsh-environment variants. The core architecture is based on a store-and-forward switching engine with a 1.6 Gbps internal switching fabric — sufficient for full-duplex saturation across all 8 × 100BASE-TX ports simultaneously.

Generation 1 (EDS-208): Single power input, standard temperature range only, no fiber uplink option. Widely deployed in early 2000s SCADA modernization projects.

Generation 2 (EDS-208A): Dual redundant power inputs (12–48 VDC), relay alarm output for power failure detection, expanded SKU matrix including multi-mode and single-mode fiber variants, and T-grade (−40°C) models. This generation became the de facto standard for IEC 61850 bay-level networking.

Compatibility Considerations: The EDS-208A is backward-compatible with EDS-208 wiring harnesses and DIN-rail mounting brackets. However, the relay alarm output pinout differs between generations — field engineers replacing EDS-208 units with EDS-208A must verify alarm circuit wiring before commissioning. The EDS-208A does not support SNMP or any management protocol; facilities requiring port-level diagnostics must migrate to the EDS-308 or EDS-405A managed switch families.

As of 2024, the EDS-208A series has entered the mature/end-of-active-development phase. Moxa continues to supply the product but no firmware or hardware revisions are planned. Long-term maintenance customers should establish buffer stock strategies, as lead times from distribution channels have extended to 8–16 weeks for certain fiber variants.

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

The following SKUs represent the complete production matrix of the Moxa EDS-208A series, classified by port configuration and media type. All units are unmanaged, DIN-rail mountable, and support dual redundant DC power input unless otherwise noted.

Copper-Only Variants (8 × 10/100BASE-TX)

• EDS-208A: 8-port unmanaged Fast Ethernet switch, standard temperature (−10 to 60°C), dual DC power input, relay alarm output.
• EDS-208A-T: 8-port unmanaged Fast Ethernet switch, extended temperature (−40 to 75°C), identical electrical specification to EDS-208A.
• EDS-208A-SS-SC: 6 × copper + 2 × 100BASE-FX single-mode fiber (SC connector), standard temperature, for long-distance uplinks up to 40 km.
• EDS-208A-SS-SC-T: 6 × copper + 2 × single-mode SC fiber, extended temperature (−40 to 75°C), rail/substation-grade.
• EDS-208A-MM-SC: 6 × copper + 2 × 100BASE-FX multi-mode fiber (SC connector), standard temperature, uplink distance up to 5 km.
• EDS-208A-MM-SC-T: 6 × copper + 2 × multi-mode SC fiber, extended temperature variant for outdoor cabinet installations.
• EDS-208A-SS-ST: 6 × copper + 2 × single-mode fiber (ST connector), standard temperature, compatible with legacy ST-terminated fiber infrastructure.
• EDS-208A-SS-ST-T: 6 × copper + 2 × single-mode ST fiber, extended temperature, for cold-climate outdoor enclosures.
• EDS-208A-MM-ST: 6 × copper + 2 × multi-mode fiber (ST connector), standard temperature, short-haul fiber uplink.
• EDS-208A-MM-ST-T: 6 × copper + 2 × multi-mode ST fiber, extended temperature, designed for process plant junction boxes.
• EDS-208A-SS-SC-80: 6 × copper + 2 × single-mode SC fiber, 80 km transmission distance, for inter-building or campus-scale industrial networks.
• EDS-208A-SS-SC-80-T: Extended temperature version of the 80 km single-mode SC variant, for extreme-environment long-haul links.
• EDS-208A-MM-SC-T (Conformal Coated): Conformal-coated PCB variant for high-humidity and corrosive-atmosphere environments (offshore platforms, coastal chemical plants).
• EDS-208A-PN: PROFINET-compatible variant with integrated PROFINET I/O device functionality, enabling integration into Siemens TIA Portal and Step 7 engineering environments.
• EDS-208A-EIP: EtherNet/IP-compatible variant, supporting Allen-Bradley ControlLogix and CompactLogix PLC ecosystems via CIP protocol.
• EDS-208A-IEC: IEC 61850-3 certified variant, meeting substation automation electromagnetic compatibility and environmental requirements for utility-grade deployments.

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

DriveKNMS maintains a dedicated inventory program for Moxa EDS-208A units, including variants that have been discontinued from Moxa's active distribution channels. Our sourcing network covers:

• New-in-box (NIB) surplus stock from decommissioned plant projects and OEM overruns, with full traceability documentation.
• Refurbished units that have undergone full functional restoration to factory specification, including power supply recapacitation and port-level throughput verification.
• Extended lifecycle support contracts for facilities operating EDS-208A switches in safety-instrumented systems (SIS) or critical infrastructure where like-for-like replacement is mandated by change management procedures.

For facilities that cannot accept refurbished units due to regulatory constraints (nuclear, pharmaceutical GMP), DriveKNMS can provide certified-new units with full chain-of-custody documentation from original Moxa-authorized distribution. Lead time quotations are available within 24 hours for standard copper variants and 48–72 hours for fiber and extended-temperature models.

Migration advisory: For sites planning to transition away from EDS-208A due to end-of-support concerns, DriveKNMS provides compatibility mapping to the Moxa EDS-308, EDS-405A, and EDS-G308 series, including port-count equivalency analysis and power budget comparison.

Quality Control for the EDS-208A Range

The EDS-208A's unmanaged architecture presents specific testing challenges: without SNMP or CLI access, port-level diagnostics must be performed through physical traffic injection and measurement. DriveKNMS applies the following test protocol to all EDS-208A units processed through our facility:

• Power input verification: Both V1 and V2 power inputs are tested independently and simultaneously across the full rated voltage range (12–48 VDC). Relay alarm output is verified for correct actuation on power-loss events.
• Port-level throughput test: Each of the 8 ports is subjected to RFC 2544 throughput, latency, and frame loss testing using a calibrated Ethernet test set. Minimum acceptable throughput is 99.5% of line rate at 100 Mbps full-duplex.
• Fiber optic power budget test: For fiber variants, optical transmit power and receive sensitivity are measured with an optical power meter. Results are compared against Moxa's published specifications (typically −20 dBm TX / −34 dBm RX for multi-mode; −15 dBm TX / −34 dBm RX for single-mode).
• Thermal cycling: T-grade units are subjected to a 4-hour thermal soak at −40°C and +75°C to verify cold-start behavior and high-temperature derating compliance.
• Backplane bus integrity: Internal switching fabric is verified by simultaneous full-load traffic injection across all ports to confirm non-blocking operation and absence of internal congestion.
• Visual and mechanical inspection: DIN-rail clip, terminal block connectors, and fiber SC/ST adapters are inspected for mechanical integrity and contact oxidation.

All test results are documented and available to customers upon request. Units that fail any test parameter are quarantined and not returned to inventory.