HIRSCHMANN MM20-M2M2M2M2SZHH Ethernet media module
HIRSCHMANN MM20-M2M2M2M2SZHH (often designated in order configurators as MM20-M2M2M2M2SZHH…) is a hot-swappable 4-port Fast Ethernet Media Module engineered for Hirschmann’s modular MICE (Modular Industrial Communication Equipment) Switch family (MS20 and MS30 series).
This module features 4 Multimode SC fiber optic ports (100Base-FX) coupled with hazardous location approvals (Class 1 Division 2 / ATEX Zone 2), providing reliable, EMI-immune optical connections for demanding industrial processing plants.
Unique Product Description
Hirschmann MM20-M2M2M2M2SZHH is a 4-port Fast Ethernet SC multimode fiber media module designed for secure, high-density optical connections within MS20/30 modular switches. Featuring dynamic hot-swappable backplane integration and certified for Class 1 Div 2 / ATEX Zone 2 hazardous areas, it enables safe network expansion and noise-free data transport across hazardous processing facilities without taking down active control networks.
Product Advantages and Features
Complete Optical Noise Immunity: Integrates 4 x 100Base-FX Multimode Duplex SC ports, completely eliminating ground loops and electromagnetic noise interference across long field cable runs.
Hazardous Location Certification (SZHH Tier): Meets stringent cUL508 / ISA 12.12.01 Class 1 Division 2 and ATEX Zone 2 standards for safe operation in potentially explosive atmospheres.
Hot-Swappable Backplane Architecture: Connects live to MS20 or MS30 basic switch units, allowing online replacement or port expansion without interrupting adjacent network traffic.
Low Power Footprint: Operates with high energy efficiency ($\approx$ 6W to 8W), drawing power directly through the switch backplane connector.
Real-Time LED Diagnostics: Front-panel LEDs provide immediate physical feedback on link activation, optical data throughput, and duplex status.
Application Cases
Refineries & Chemical Processing Plants: Deployed in Class 1 Div 2 hazardous control zones to connect remote PLC racks and safety instrumented systems (SIS).
Oil & Gas Pipeline Stations: Interconnects distributed RTUs along pipelines where hazardous area ratings and fiber-optic isolation are required.
High-Noise Industrial Manufacturing: Used near high-voltage motor drives and induction furnaces where electrical noise renders copper twisted-pair cabling unusable.
Water/Wastewater Treatment Facilities: Connects remote pumping stations across expansive plants while providing isolation against lightning surges and ground potential differences.
Other Models in the Same Series
The Hirschmann MICE MM20/MM30 Series offers multiple combinations of copper, fiber, and hazardous/environmental ratings:
| Model Part Number | Port Configuration | Environmental / Approval Tier |
| MM20-M2M2M2M2SZHH | 4 x Multimode SC Fiber (100Base-FX) | Hazardous Location (Class 1 Div 2 / ATEX) |
| MM20-M2M2M2M2SAHH | 4 x Multimode SC Fiber (100Base-FX) | Standard Temp ($0^\circ\text{C}$ to $+60^\circ\text{C}$) |
| MM20-M2M2M2M2EBH | 4 x Multimode SC Fiber (100Base-FX) | Extended Temp ($-40^\circ\text{C}$ to $+70^\circ\text{C}$) + Conformal Coating |
| MM20-T1T1T1T1SAHH | 4 x 10/100Base-TX (RJ45 Copper) | Standard Temp ($0^\circ\text{C}$ to $+60^\circ\text{C}$) |
| MM20-Z6Z6SAHH | 4 x Fast Ethernet SFP Slots | Standard Temp SFP Module |
| MM20-Z6Z6EBH | 4 x Fast Ethernet SFP Slots | Extended Temp SFP Module + Conformal Coating |
Installation and Maintenance
Installation
Electrostatic Safety: Attach an ESD grounding wrist strap before removing the module from its antistatic package.
Module Insertion: Align the guide rails of the MM20-M2M2M2M2SZHH with an open media slot on the host MS20/MS30 switch backplane. Slide it inward until the backplane connector locks firmly.
Mechanical Fastening: Hand-tighten the top and bottom captive thumbscrews on the module faceplate to secure the module and ground its chassis.
Fiber Cabling: Remove the protective rubber plugs from the SC ports and connect $50/125\,\mu\text{m}$ or $62.5/125\,\mu\text{m}$ multimode SC fiber optic patch cables (ensuring Tx to Rx crossover).
Maintenance
Hot-Swap Replacement: If replacing a module in an active network, disconnect the fiber patch cords, loosen the thumbscrews, and pull out the unit. Insert the replacement module without powering off the host switch.
Port Protection: Keep protective rubber dust caps on all unpopulated SC ports to prevent dust particles from contaminating the internal optical lenses.
Optical Fiber Cleaning: If signal attenuation occurs, clean the SC optical connectors using an optical lint-free cleaning pen or optical-grade alcohol wipes before re-plugging.