Westermo Merlin 4609 - IEC 61850-3 Industrial Cellular Router
LTE Cat-4, 4xETH, 2xRS232/485, 6xDI, 2xDO, GNSS, TPM Security
The Merlin 4609 is a compact, rugged cellular router engineered for direct deployment in medium-voltage power substations and railway environments without requiring additional isolation infrastructure. It consolidates multiple local protocols (Modbus RTU/TCP, DNP3, IEC 61850) into a single secure LTE connection, reducing integration complexity and system cost while maintaining full compliance with IEC 61850-3 Class 1 and EN 50121-4 standards.
Built for critical infrastructure using industrial-grade components and redundant design practices, the Merlin 4609 achieves an 825,000-hour MTBF rating and operates across -40 to +70°C—demonstrating proven reliability in demanding environments. The device features integrated cybersecurity architecture with Trusted Platform Module (TPM) hardware, Secure Boot verification, and industry-standard encryption protocols. Native RTU capabilities with 6 digital inputs and 2 relay outputs enable direct device control without external modules, reducing points of failure and system complexity.
Key Features
- Direct Substation Deployment
- IEC 61850-3 Class 1 compliance eliminates need for external galvanic isolation equipment
- 4 kVrms isolation on power and Ethernet ports protects control systems from surge events and transient faults
- Multi-Protocol Network Consolidation
- Bridges legacy devices (Modbus RTU, DNP3) and modern substations (IEC 61850) through a single outbound connection
- Reduces field wiring, simplifies architecture, and lowers integration cost
- Industrial-Grade Security
- Trusted Platform Module (TPM) secures cryptographic keys independent of system firmware
- Secure Boot prevents unauthorized software modification
- 802.1X authentication, IPSec encryption, and stateful firewall as standard
- Native RTU Functionality
- 6 digital inputs and 2 relay outputs for direct device control without external modules
- Software-configurable RS-232/RS-485 serial ports for legacy system integration
- Proven Reliability for Critical Systems
- 825,000-hour MTBF, -40 to +70°C operating range, 5-year warranty
Typical Applications
- Power Utilities & Substations
- Medium-voltage substation automation and remote monitoring
- SCADA connectivity for distributed generation and microgrid management
- Railway & Trackside Infrastructure
- Trackside signaling and control systems with EN 50121-4 compliance
- Remote monitoring of railway infrastructure in areas without fixed broadband
- Industrial & Energy Applications
- Remote pipeline and facility monitoring, oil/gas infrastructure connectivity
Technical Specifications
| Specification |
Value |
| Standards Compliance |
IEC 61850-3 Class 1, EN 50121-4, EN 62368-1 |
| Cellular Connectivity |
LTE Cat-4 (EMEA: 900/1800 2G, B1/B8 3G, B1/B3/B7/B8/B20/B28 LTE) |
| Network Interfaces |
4 × 10/100 Mbit/s Ethernet (RJ45), 2 × 1000 Mbit/s SFP |
| Galvanic Isolation |
4.0 kVrms on power supply and Ethernet ports |
| Protocol Support (SCADA) |
IEC 60870-5-104, IEC 60870-5-101, IEC 61850, Modbus RTU/TCP, DNP3, MQTT |
| Local I/O |
6 digital inputs, 2 relay outputs (220 VDC, 2 Amp), 2 configurable serial ports (RS-232/RS-485) |
| Power Requirements |
9.6–60 VDC, 7 W typical, 100 ms hold-up time |
| Operating Environment |
-40 to +70°C, 5–95% relative humidity, IP40 ingress protection |
| MTBF & Warranty |
825,000 hours (Telcordia), 5-year warranty |
Security Architecture
- Trusted Platform Module (TPM) stores and protects cryptographic keys independent of system firmware
- Secure Boot verifies and authorizes only manufacturer-signed software, preventing unauthorized modifications
- IPSec VPN with IKEv2, X.509 certificates, AES-256, and SHA-512 for encrypted site-to-site connectivity
- 802.1X authentication and stateful inspection firewall for network access control
- MQTT protocol translation enables secure communication with cloud-based monitoring systems
Certifications & Standards
- IEC 61850-3 Class 1 (Power Utility Substation Automation)
- EN 50121-4 (Railway Signalling and Telecommunications)
- EN 62368-1 (Safety – Communication Technology)
- EN/IEC 61000-6-2 (Industrial EMC Immunity), EN/IEC 61000-6-4 (Industrial Emissions)