HD67C03-2-G43-VPN-B2 – Industrial RS232 to MQTT Broker Converter with VPN, LAN and LTE SIM

HD67C03-2-G43-VPN-B2 Converter – RS232 to MQTT Broker with VPN, LAN and LTE SIM

The HD67C03-2-G43-VPN-B2 is an advanced industrial converter designed to interface RS232 devices with MQTT Broker infrastructures while providing secure VPN tunneling for remote, mission-critical and distributed applications. Based on the proven HD67C03 architecture, this model extends connectivity with LAN Ethernet and LTE SIM, while adding a VPN service for encrypted communication across public or untrusted networks. Its compact Housing type B, DIN-rail mounting and wide temperature range make it suitable for harsh industrial environments.

The device acts as an intermediary between serial RS232 equipment and modern IoT or IIoT platforms relying on MQTT messaging. It supports message publishing, subscription and full Broker-level communication with multiple MQTT clients simultaneously. The VPN functionality ensures that communication is securely tunneled, allowing safe remote access, encrypted telemetry and protected industrial data exchange.

Built according to the specifications provided in the technical manual, the converter offers reliable isolation, robust terminal block connectors and compatibility with the SW67C03 configuration software. The LTE module supports MicroSIM, while Ethernet remains available as the primary interface for MQTT and VPN traffic.

RS232 to MQTT Broker – secure and structured data integration

The HD67C03-2-G43-VPN-B2 is designed for transforming data from legacy RS232 devices into MQTT Broker topics, enabling full integration with IoT platforms, cloud services, SCADA systems and data analytics environments.

• RS232 communication up to 115200 bps,
• publishing serial data as MQTT messages,
• subscribing to MQTT topics and forwarding commands to RS232,
• payload mapping (JSON, Base64, float, integer and more),
• support for multiple MQTT clients simultaneously.

The embedded MQTT Broker allows other devices and applications to connect directly to the converter, creating a local IoT hub at the network edge.

VPN service – encrypted and secure industrial communication

The key feature of this model is the integrated VPN service, which creates secure tunnels for industrial traffic. This ensures encrypted data transfer even in remote or unprotected networks, including LTE-based installations.

• secure VPN tunneling for industrial and telemetry systems,
• encrypted communication between remote nodes,
• protected remote access to serial equipment,
• elimination of risks associated with public IP exposure,
• compatible with IoT/IIoT cloud and SCADA infrastructures.

The VPN layer allows safe deployment even in distributed environments where direct connections are not possible or not secure.

LAN + LTE SIM – reliable dual connectivity

The HD67C03-2-G43-VPN-B2 provides two types of network connectivity:

• Ethernet (RJ45) – primary communication path for MQTT and VPN,
• LTE SIM – mobile connectivity using MicroSIM cards.

This dual architecture ensures:

• network redundancy (cellular fallback),
• remote access in distributed installations,
• operation in locations without wired Ethernet,
• flexible deployment for field and mobile systems.

The LTE interface allows MQTT Broker and VPN communication even in fully remote deployments.

Configuration via SW67C03 and integrated webserver

The converter is configured using the SW67C03 Compositor software and the integrated webserver. These tools provide full control over MQTT message structure, RS232 parameters and VPN settings.

The configuration software enables:

• setting of RS232 parameters,
• MQTT topic and client management,
• VPN configuration and security profiles,
• payload mapping and variable structuring,
• firmware updates and diagnostics.

Software download link: DOWNLOAD

Industrial design – Housing type B, DIN rail mount and wide temperature range

The converter is engineered for industrial environments requiring durability and long-term reliability. Key physical features include:

• Housing type B – compact and rugged,
• Dimensions: 70 × 60 × 95 mm,
• Mounting: