HD67C03-5-G43-E-VPN-B2 – Industrial RS485 to MQTT Broker Converter with LAN, LTE SIM, eSIM and VPN

HD67C03-5-G43-E-VPN-B2 – RS485 to MQTT Broker Converter with LAN, LTE SIM, eSIM, VPN and Housing Type B.

The HD67C03-5-G43-E-VPN-B2 is a highly advanced industrial communication converter designed to integrate RS485 serial devices into modern IoT and IIoT ecosystems using the MQTT Broker protocol. As one of the most feature-rich variants within the HD67C03 product line, this model combines wired Ethernet, LTE mobile communication via MicroSIM, integrated eSIM support and a full VPN service. This makes it an ideal solution for installations that require secure remote connectivity, communication redundancy and long-term operational reliability under harsh industrial conditions.

The unit is housed in a robust Housing Type B enclosure and equipped with screw-type terminal blocks, ensuring durable and vibration-resistant wiring. Designed for DIN rail mounting, the device integrates seamlessly with industrial control cabinets and distributed networks where stability, safety and consistent data flow are essential.

Technical specifications are based on the HD67C03-5-G43-E-VPN-B2 datasheet and the official MN67C03 technical manual, which documents full LTE modem operation (MicroSIM), the presence of an eSIM module, the LTE antenna interface (SMA Female) and all MQTT Broker and RS485 communication mechanisms.

RS485 to MQTT Broker – powerful integration for industrial IoT architectures

The device converts RS485 data into MQTT structures, enabling legacy industrial equipment to participate in modern cloud-based and IIoT systems. This allows seamless exchange of field-level data with platforms such as SCADA, BMS, monitoring dashboards and analytics engines.

Key RS485 features include:

• data transmission speeds up to 115200 bps,
• 3-pin screw terminal connector for reliable wiring,
• long-distance communication with differential signalling,
• DIP-switch bus termination (as specified in MN67C03),
• support for multidrop network topologies.

As an MQTT Broker, the device supports:

• multiple simultaneous MQTT clients,
• publish/subscribe messaging,
• custom topic structure and payload mapping,
• integration with cloud platforms and edge servers,
• secure routing of RS485 data into MQTT infrastructure.

Triple connectivity: LAN + LTE SIM + eSIM

One of the major advantages of the G43-E variant is its triple communication architecture:

• Ethernet LAN (RJ45) – the primary interface for local configuration and MQTT data transfer,
• LTE mobile communication via MicroSIM,
• Integrated eSIM – enabling remote provisioning and mobile connectivity without a physical SIM card.

This multi-layered communication approach offers:

• network redundancy between LTE/eSIM and LAN,
• operation in locations with no cable infrastructure,
• secure, continuous IoT connectivity for remote installations,
• support for external antennas via SMA Female, allowing improved LTE signal performance.

Such flexibility makes the converter suitable for distributed automation, energy monitoring, telemetry, infrastructure supervision and environmental control systems.

VPN service – secure access and protected IoT communication

The integrated VPN service is the defining feature of the VPN-B2 model. It provides a secure, encrypted communication tunnel suitable for industrial applications requiring:

• protection of sensitive operational data,
• secure access to remote equipment,
• segmented industrial networks and infrastructure,
• communication between field devices and private cloud servers,
• strong cybersecurity for critical installations.

In scenarios involving remote substations, distributed assets, transport systems or energy networks, VPN functionality ensures encrypted end-to-end communication between field devices and central platforms.

Configuration via SW67C03 and integrated diagnostic webserver

The device is configured using the SW67C03 configuration suite, available here:
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Using SW67C03, you can configure:

• RS485 parameters,
• LTE SIM and eSIM profiles,
• MQTT Broker topics, QoS and data mapping,
• VPN settings such as profiles, certificates and routing rules,
• LAN network configuration,
• data routing and communication paths,
• firmware updates and general diagnostics.

The device also provides an integrated webserver, enabling:

• real-time communication status monitoring,
• diagnostic information and basic logs,
• MQTT client activity overview,
• quick access to device health and system parameters.

Industrial construction – Housing Type B and DIN rail mounting

Built for demanding industrial environments, the HD67C03-5-G43-E-VPN-B2 features:

• Housing Type B (Modulbox 4M),
• Dimensions: 70 × 60 × 95 mm,
• DIN rail mounting (35 mm),
• Weight: approx. 200 g,
• Screw-type terminals for all wiring connections,
• Operating temperature range: -40°C to +85°C.

Its ruggedised design ensures resistance to vibrations, electrical noise and environmental stress, making it suitable for:

• industrial control systems,
• mobile and field-mounted installations,
• energy and utility infrastructure,
• transport and logistics systems,
• outdoor monitoring applications.

Technical specifications

• Ports: 1× RS485, 1× Ethernet, SIM Card, eSIM
• Special function: VPN service
• RS485 protocol: differential serial bus
• MQTT Broker: full publish/subscribe support
• Connectors: RS485 – 3-pin screw terminal; RJ45 + SIM + eSIM
• RS485 speed: up to 115200 bps
• MQTT speed: 10/100 Base-T Autosensing
• Power supply: 8…24 V AC or 12…35 V DC
• Operating temperature: -40°C…+85°C
• Dimensions: 70 × 60 × 95 mm
• Weight: approx. 200 g
• Software: SW67C03
• Order code: HD67C03-5-G43-E-VPN-B2

If you need help selecting the right RS485/MQTT Broker converter with LTE, eSIM and VPN support, or if you want to verify compatibility with your automation infrastructure, our engineering team is ready to provide expert assistance.