HIRSCHMANN MM20-T1T1T1T1SAHH 4-port Fast Ethernet Copper Cable Media Module
The HIRSCHMANN MM20-T1T1T1T1SAHH (often designated in order configurators as MM20-T1T1T1T1SAHH…) is a hot-swappable 4-port Fast Ethernet copper Media Module designed specifically for Hirschmann’s modular MICE (Modular Industrial Communication Equipment) Switch family (MS20 and MS30 series).
Unlike the SFP-based variants, this module features 4 integrated RJ45 copper ports supporting 10/100Base-TX Ethernet, making it a workhorse for direct device connectivity in factory automation cabinets and control networks.
Unique Product Description
Hirschmann MM20-T1T1T1T1SAHH is a 4-port Fast Ethernet RJ45 media module engineered for localized copper field connections within MS20/30 modular switches. Featuring auto-negotiation, auto-crossing (Auto-MDI/MDI-X), and hot-swappable backplane integration, it allows industrial engineers to expand copper port density on the fly without disrupting active control networks. Housed in a compact IP20 enclosure with heavy EMC shielding, it delivers reliable 10/100 Mbps data throughput across noise-heavy plant environments.
Product Advantages and Features
Direct Copper Connectivity: Equipped with 4 x RJ45 10/100Base-TX ports, eliminating the need for separate external transceivers when connecting local field devices.
Auto-MDI/MDI-X & Auto-Negotiation: Automatically detects line speed (10 Mbps or 100 Mbps) and duplex mode (Half or Full) while eliminating the need for crossover patch cables.
Hot-Swappable Backplane Architecture: Plugs directly into live MS20 or MS30 basic switch units, allowing line maintenance or expansion without powering down the main switch.
Standard Industrial Hardening (SAHH Designation):
Operating Temperature: $0^\circ\text{C}$ to $+60^\circ\text{C}$.
Storage Temperature: $-40^\circ\text{C}$ to $+70^\circ\text{C}$.
Vibration/Shock Resistance: IEC 60068 compliant for high-vibration machinery environments.
Energy-Efficient Design: Low power footprint (typically ~3W to 5W) drawn directly from the host switch backplane.
Diagnostic Port LEDs: Front-facing LEDs display real-time physical Link status, Data activity, and Port speed for rapid troubleshooting.
Application Cases
Factory Floor Machine Racks: Directly connects local PLCs, HMIs, motor drives, and vision sensors to an MS20/MS30 switch inside control panels.
Assembly & Packaging Lines: Serves as a modular expansion module when new automation cells or robotic stations are added to an existing Ethernet ring.
Building Management Systems (BMS): Integrates HVAC controllers, security gateways, and access control panels across industrial facility sub-networks.
Control Room Cabinets: Provides high-density copper drops for local diagnostics equipment, engineering workstations, and data logging servers.
Other Models in the Same Series
The Hirschmann MM20 / MM30 Series provides extensive flexibility depending on whether your application demands copper, fiber, or SFP ports:
| Model Part Number | Port Type / Configuration | Environment / Key Feature |
| MM20-T1T1T1T1SAHH | 4 x 10/100Base-TX (RJ45 Copper) | Standard Temp ($0^\circ\text{C}$ to $+60^\circ\text{C}$) |
| MM20-T1T1T1T1EBH | 4 x 10/100Base-TX (RJ45 Copper) | Extended Temp ($-40^\circ\text{C}$ to $+70^\circ\text{C}$) + Conformal Coating |
| 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 |
| MM20-M4M4T1T1 | 2 x Multimode SC Fiber + 2 x RJ45 | Hybrid Fiber/Copper Module |
| MM22-T1T1T1T1 | 4 x 10/100Base-TX (RJ45 Copper) | Power over Ethernet (PoE) Support |
Installation and Maintenance
Installation
Electrostatic Safety: Always attach an ESD grounding wrist strap before handling the card.
Insertion: Align the module with the guide rails of an open slot on the host MS20 or MS30 switch backplane. Push firmly until the module connector clicks into place.
Securing: Fasten the two captive thumb screws on the module faceplate to lock it into the switch frame.
Cabling: Plug standard Cat5e or Cat6 shielded twisted-pair (STP) Ethernet cables into the RJ45 ports.
Maintenance
Hot-Swap Replacement: To replace a faulty port or module during operation, disconnect the RJ45 cables, loosen the thumbscrews, slide the module out, and insert the new unit.
Status Inspection:
Link/Data LED Solid Green: Valid 100 Mbps link established.
Blinking Green/Yellow: Active network traffic.
LED Off: Cable disconnected, cable length exceeds 100 meters, or connected link partner is unpowered.
Port Protection: Keep protective plastic dust covers over unpopulated RJ45 ports to prevent dust ingress in dirty industrial environments.