A signal, a camera, and no cable at the curb
Smart traffic (ITS) networks signals, runs V2X vehicle-road coordination, watches the road, and guides drivers through signals, enforcement cameras, RSU roadside units, magnetic detectors, and VMS signs. Most of that gear sits outdoors with no wired network, so 4G or NB-IoT is the link. SimtoLink modules for this work are 4G / 5G / NB-IoT, industrial-grade, with UART, SPI, and I2C. The company supports 500+ enterprise customers and has connected more than 10 million traffic devices.
Where the module sits at the roadside
A signal controller, an enforcement camera, an RSU, and a magnetic detector in the pavement do not share a bandwidth. These are the usual ITS jobs, and the radio that tends to fit.
Signal controllers on the network
A junction signal joins the signal-control platform over 4G, for a green wave, timing, and remote retuning. Junctions move more traffic, and the link can join SCATS or SCOOT.
Enforcement cameras and checkpoints
Violation capture and a checkpoint send pictures and video over 4G, for recognition, evidence upload, and off-site enforcement. That is the path into the traffic-police platform.
Magnetic vehicle detectors
A magnetic sensor reports flow over NB-IoT at low power, for counts, signal timing, and adaptive control at the junction. It is simple to put in, needs no mains supply, and stays cheap.
VMS signs
A variable message sign takes guidance over 4G: road conditions, a diversion, or an emergency message. Drivers see it before they are in the queue.
Parking and illegal-parking capture
A magnetic sensor in a curb space, or a snapshot of illegal parking, goes up through the module. That supports parking guidance, evidence, and the rest of a city's parking operation.
What a cabinet at the curb asks of the module
- Coverage across the city: Roadside gear is everywhere. Several operators and bands are what hold coverage and a failover handover.
- Weather at the roadside: Outdoor units need −40°C to 85°C and IP65/IP67 dust and water protection.
- A signal that cannot drop: Signals and enforcement gear cannot sit through an outage. The module has to stay up 7×24.
- ITS protocols the controller already speaks: Signals, cameras, and sensors over TCP, UDP, MQTT, and NTCIP.
- From a sample to volume: SimtoLink modules span 2G, 3G, 4G, and 5G, with documentation, an SDK, and production supply.
Which radio fits a signal, and which fits a sensor in the road
Bandwidth, delay, and power do not line up the same way for a camera and a magnetic detector. Device type, the job, and how little downtime it can take should decide the module. The rows below are the usual pairing at the roadside.
| Job | Radio | What matters |
|---|---|---|
| Signals, enforcement cameras, VMS | 4G | A wide pipe, live links, pictures and video back, the signal platform |
| Magnetic detection, smart parking | NB-IoT | Very low power, infrequent reports, no mains supply, low cost |
| RSU, V2X | 4G 5G | Low delay, high reliability, C-V2X, a link to the cloud |
| Checkpoints, video surveillance | 4G | A wide pipe, video backhaul, upload as it happens |
How SimtoLink fits an ITS program
For roadside gear, the modules are industrial designs that hold temperature, dust, and water, with technical support 7×24. 4G is the recommendation for signals, enforcement cameras, VMS signs, and RSUs, where the pipe has to be wide. NB-IoT fits magnetic detection and parking, which report rarely and draw little. An SDK a systems team can bring up quickly, work with mainstream chip vendors, and a named account manager come with the module.
A roadside project is taken from the requirements and the radio choice, through a prototype at one junction, and into volume. Documentation, the AT command set, an SDK, and sample code ship with the module, and supply is planned for a build and for the years the cabinet stays at the curb. Vehicle-road coordination keeps adding roadside units, and the module line will follow that.
How an ITS project usually moves
A roadside project usually moves in this order:
The choice turns on device type (signal, enforcement camera, magnetic sensor, or RSU), bandwidth (video wants a wide pipe; a magnetic sensor can stay low power), the curb (outdoors wants a wide temperature range, dust, and water protection), and reliability (a signal cannot sit through an outage). Start at one junction and check the module and the link into the signal platform. Signals and enforcement cameras should use 4G. Magnetic sensors can use NB-IoT.
A radio at the roadside moves more traffic, supports safer enforcement, and is what connected vehicles need on the street. SimtoLink has supplied modules to traffic police, transport departments, and system integrators.