Engineered for reliable facility telemetry and legacy network modernization, this industrial 4G LTE Cat.1 DTU securely bridges RS232/RS485 serial data into cellular networks. It features native MQTT integration and Modbus RTU to JSON conversion, providing a robust edge node for distributed SCADA systems and cloud-based asset monitoring in harsh environments.
Product model | VT-DTU300 | VT-DTU500C | VT-DTU500E | VT-DTU500SA | VT-DTU500G | |
Product Type | High performance 4g DTU 4G Industrial serial port server | |||||
Main Function | WiFi/Eth/CAT1 4G Single serial port server /includes router function | |||||
Interface | RS485：3.5mmTerminal block | RS232/RS485
| LAN:RJ45、485：connection terminal 、232：DB9 | |||
Power supply | 9 ~ 24V DC screw terminal | 9 ~ 24V DC Round hole mode (Can be customized | 9 ~ 48V DC Round hole mode (Can be customized terminal power supply) | |||
Communication | ||||||
Ethernet | DC9V~24V | DC9V~48V | ||||
Frequency Band | LTE-FDD: B1, B3, B5, B8 | LTE-FDD: B1, B3, B5, B8 | LTE-FDD: B1, B3, B5, B7, B8, B20 | LTE-FDD: B1, B2, B3, B4, B5, B7, B8, B28,B66 | LTE-FDD: B1, B2, B3, B4, B5, B7, B8, B20,B28,B66,B71 LTE-TDD: B34,B38,B39,B40,B41 | |
GSM:B3/B8 | GSM:B3/B8 | GSM/GPRS/EDGE: 900/1800 MHz | GSM/GPRS/EDGE: 850/900/1800/1900 MHz | GSM/GPRS/EDGE: 850/900/1800/1900 MHz | ||
Serial specification | ||||||
Baud rate | 300~921600bps | |||||
Parity bit | None, odd, even, mark, space | |||||
Data bit | 5 ~ 8 bits | |||||
Software | ||||||
Protocol | ETHERNET, IP, TCP, UDP, HTTP, ARP, ICMP, DHCP, DNS | |||||
Configuration | VirCom, WEB browser, device management library | |||||
Transfer protocol | Modbus TCP、MQTT、JSON、HTTP | |||||
Modbus gateway | Support multi-host mode, storage mode, Pre-configuration table (ZLMB) mode | |||||
Operating mode | TCP/IP Direct communication, virtual serial port mode | |||||
Environment | ||||||
Operating temperature | -40~85℃ | |||||
Storage temperature | -45~120℃ | |||||
Humidity range | 5~95% relative humidity | |||||
The VT-DTU500C is a highly reliable LTE CAT-1 cellular gateway that supports 2G GPRS fallback. It achieves transmission speeds up to 10Mbps downlink/5Mbps uplink, significantly outperforming traditional 2G options.
Core Edge-Computing Capabilities
Seamless Modbus-to-JSON Conversion: Directly poll your legacy Modbus RTU devices and push parsed JSON payloads to the cloud without an expensive intermediate edge PC.
Native MQTT Integration: Built-in support for MQTT publish/subscribe topics, QoS settings, and keep-alive parameters to assure reliable telemetry for standard brokers (AWS, AliCloud or private).
Future-Proof Cat.1 Connectivity: Effortlessly transition from older 2G/3G networks to fast LTE Cat.1 (10Mbps down / 5Mbps up) with reliable 2G fallback for remote deployments.
Versatile Configuration: Control large deployments on the ground via serial AT commands or remotely via OTA updates and centralized cloud management.
A specially designed watchdog circuit ensures long-term stable operation of the 4G cellular modem. The product operates in industrial temperature ranges from -40°C to 85°C, making this rugged 4G DTU suitable for the most demanding environments.
Critical Applications:
SCADA Modernization: Replace legacy serial networks with cellular technology without changing existing logic in field PLCs.
Smart Grid & Power Infrastructure: Ensure 24/7 uptime with built-in hardware watchdog to monitor remote distribution cabinets.
Environmental & Hydrological Stations: Collect meteorological data from off-grid locations in extreme temperatures (-40°C to 85°C).
Water Treatment & Pipeline Monitoring: Push pressure and flow rate telemetry directly to city dashboards in real-time over MQTT.
A: Blind spots are a fact of life in industrial environments. The VT-DTU500C features an independent hardware watchdog and more sophisticated “Keep-Alive” features. If it detects a network drop it automatically resets the cellular module to reconnect. But the actual modem does not keep the large quantities of historical data during a long outage. If zero-data-loss is critical for your local bus during outages, we strongly suggest installing our [Active 2-Channel RS485 Caching Hub] between your PLC and the gateway.
A. The gateway is open to everyone and it accepts standard Nano SIM cards. It works perfectly on commercial LTE data plans and dedicated M2M (Machine-to-Machine) IoT SIMs. The gateway will connect as long as your carrier supports LTE Cat.1 bands (with 2G fallback if needed) and your SIM has SMS enabled (if you want to configure the modem remotely via SMS AT commands).
A: The VT-DTU500C does not use a custom Linux OS for user scripting so as to ensure maximum stability and avoid firmware crash at the edge level. Instead, the built-in Modbus-to-JSON engine automatically parses your RTU registers into a standardized, lightweight JSON key/value pair format. This is a standard payload that is universally supported and can be easily routed and mapped by the native payload formatters within AWS IoT Core, Azure IoT Hub or AliCloud.
A: LTE Cat.1 (10Mbps down / 5Mbps up) is the perfect “sweet spot” for industrial telemetry. Cat.4 has a higher video-streaming speed, but it consumes significantly more power and produces significantly more heat. Cat.1 offers more than enough bandwidth for SCADA systems transmitting Modbus data, MQTT topics and JSON strings, while ensuring ultra-low power consumption and thermal stability – crucial for continuous 24/7 operation within small, unventilated outdoor control cabinets.
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