Wireless transparent transmission of serial data
A SimtoLink DTU (data transfer unit) sends serial data (RS232/RS485) over 4G LTE Cat.1/Cat.4 or NB-IoT as a transparent stream to a cloud server. It speaks TCP client, UDP, MQTT, and HTTP. It networks scattered meters, PLCs, EV chargers, vending machines, and kiosks. It plugs in and needs no programming.
The industrial design takes a wide DC input, 9–36 V, so vehicle and outdoor supply swings are acceptable. It runs from −40 °C to 85 °C. SimtoLink DTUs are already in chargers, vending machines, kiosks, and industrial equipment, with more than 200,000 units shipped.
Specifications and protocols
SimtoLink DTUs come in several builds by radio and serial configuration, for remote networking on different sites. The table is a typical reference:
| Radio | Typical use | What decides it |
|---|---|---|
| 4G LTE Cat.1/4 | EV chargers, vending machines, video | High bandwidth, live data, more traffic |
| NB-IoT | Smart meters, environmental monitoring, infrequent reports | Low power, low cost, wide coverage |
Serial is RS232 or RS485, baud 300 to 921600. Protocols are TCP client, UDP, MQTT, and HTTP. Multi-center reporting can reach several servers at once. The link reconnects after a drop, and data can be cached offline. VPN and a keep-alive heartbeat are supported, as are SMS and voice wake-up, remote configuration, and OTA firmware. Specs vary by model. SimtoLink supplies a selection table and a configuration tool.
Typical applications and what changed
From charger operations to vending networks and online environmental monitoring, a DTU covers remote networking of scattered devices in several industries. Typical jobs and the results:
Remote monitoring and fault diagnosis on chargers
One charger company fitted DTUs on 500 AC chargers and passed BMS data through to the operations platform. Remote monitoring, fault diagnosis, and OTA updates followed, and service got faster.
Vending sales and stock reports
Makers report sales, stock, and fault alarms to headquarters, so restocking and service can be scheduled from a distance.
Outfall monitoring
One environmental firm put DTUs on 200 outfalls and passed flowmeter and water-quality data to the regulator, meeting online-monitoring and data-compliance rules.
Remote service of industrial equipment
PLCs, drives, and meters join the network through a DTU for remote collection, fault alarms, and remote debugging, which cuts site visits.
Selection and deployment
- Serial: Pick one port or two to match the device, and match baud, data bits, and parity.
- Radio: Choose 4G when the flow is high and the link must stay live. Choose NB-IoT when the flow is small, cost matters, and coverage has to be wide.
- Security and a fixed IP: If you need a fixed IP or encrypted transport, pick a VPN model and match the server configuration.
- Site: Industrial, vehicle, and outdoor jobs want a wide-temperature, lightning-protected build. For a large rollout, pilot a small batch first and prove the network and the protocol.
- Configuration: SimtoLink supplies a DTU configuration tool and cloud integration, with remote configuration and OTA.
Rollout and service
A practical sequence for a DTU project:
After a drop, the link comes back on its own, and cached data is held. VPN settings have to match the server. SimtoLink supplies the configuration tool, cloud integration, and service support. For a large rollout, prove the network and the protocol on a pilot first.
Support
SimtoLink helps with DTU selection and cloud integration, including multi-center reporting and VPN, plus the configuration tool and service support. A product manual and a proposal price are available.