Application of Serial to Ethernet Converter in Traffic Signal Control: How to Ensure Real-Time Performance?
The Real-Time Challenges of Traffic Signal Control

The pulse of urban traffic beats with the switching of every traffic light. During morning rush hour, when vehicle flow surges toward intersections like tidal waves, if traffic signals fail to dynamically adjust timing based on real-time road conditions, congestion will spread like dominoes. According to statistics, major cities in China suffer passage efficiency losses exceeding 30% due to unreasonable signal timing. Traditional traffic signal systems rely on physical connections between local serial devices and control centers, limited by cable length and device dispersion, making global optimization difficult. The emergence of serial to Ethernet converter provides critical technical support for solving this problem—by connecting RS232/485 serial devices to TCP/IP networks, they establish a high-speed traffic data channel covering the entire city.

1. Serial to Ethernet Converter: The "Nerve Center" of Traffic Signal Control

1.1 From Physical Connections to Networking

Traditional traffic signal systems use RS485 buses to connect devices such as inductive loop detectors, radar sensors, and signal controllers, with communication distances typically not exceeding 1.2 kilometers. When extending to cross-regional management, multi-level relay devices must be deployed, drastically increasing system complexity. Serial to Ethernet converters achieve "infinite-distance" communication between devices and control centers by converting serial protocols (e.g., Modbus RTU) into network protocols (e.g., Modbus TCP). For example, the USR-TCP232-410s dual serial to Ethernet converter supports simultaneous RS232 and RS485 operation, with industrial-grade design (-40℃~85℃ wide temperature operation) to adapt to harsh outdoor environments, providing stable network access points for traffic devices.

1.2 The Efficiency Revolution of Centralized Multi-Device Management

A single serial to Ethernet converter can connect 8 or more traffic devices simultaneously. In a traffic hub renovation project in a first-tier city, by deploying USR-TCP232-410s, 12 directional signal lights, 6 sets of inductive loop detectors, and 4 electronic police cameras were unifiedly connected to a local area network. The control center could obtain real-time data from all devices through a single IP address. This centralized management model reduced device configuration time from individual tuning of each device to batch operations, improving operational efficiency by over 80%.

1.3 Technical Breakthroughs in Protocol Compatibility

The traffic field uses multiple communication protocols: signal controllers adopt the CJ/T 305-2009 standard, electronic police use the GB/T 28181 protocol, and weather monitoring stations rely on the MQTT protocol. The built-in protocol conversion engine of the USR-TCP232-410s enables mutual conversion between Modbus RTU/TCP, transparent transmission, custom JSON, and other protocols. In a smart traffic project in Shenzhen, this device successfully unified 23 device protocols from different manufacturers into TCP/IP standards, eliminating "language barriers" between systems.

2. Real-Time Performance Guarantee: A Three-Dimensional Design from Hardware to Software

2.1 The Performance Foundation at the Hardware Layer

Real-time performance first depends on hardware response speed. The USR-TCP232-410s adopts a Cortex-M7 processor with a 400MHz clock frequency, paired with 256KB SRAM and 512KB Flash, enabling lossless processing of 2,000 frames of data per second. Its dual watchdog mechanism (hardware watchdog + software watchdog) ensures continuous stable operation in extreme environments (-40℃~85℃), with fault self-recovery time less than 3 seconds. During actual testing in Harbin at -35℃ in winter, the device ran continuously for 180 days without communication interruptions.

2.2 Transmission Optimization at the Network Layer

Traffic data features "small packets with high frequency": a single inductive loop detector reports vehicle flow data every 0.1 second, with each transmission only 8 bytes. To address this characteristic, the USR-TCP232-410s supports five operating modes:

• TCP Client Mode: Actively connects to the control center, suitable for fixed IP scenarios.
• UDP Mode: Reduces latency to under 5ms, ideal for emergency event reporting.
• HTTPD Client Mode: Directly pushes data to cloud platforms, reducing intermediate links.
  In a project on Chengdu's Second Ring Road Elevated Highway, using UDP mode to transmit vehicle detection data reduced system response time from the traditional 200ms to 15ms, completely eliminating lag in signal timing adjustments.

2.3 Algorithmic Innovation at the Software Layer

The core of real-time performance guarantee lies in data processing efficiency. The USR-TCP232-410s adopts a three-level caching architecture:

• Hardware FIFO Cache: A 16KB circular buffer prevents data overflow.
• Protocol Parsing Cache: Dynamically allocates memory to support simultaneous processing of 16 TCP connections.
• Application Layer Cache: Custom JSON format reporting reduces server parsing pressure.
  In Hangzhou's "City Brain" project, the device's edge computing function enabled data preprocessing: performing sliding average filtering on 10 consecutive frames of vehicle flow data and only uploading changes exceeding 15%, reducing network bandwidth usage by 70% while ensuring real-time performance of critical data.

410s

RS485+RS232MQTT+SSLEdge Computing

3. Analysis of Typical Application Scenarios

3.1 Dynamic Signal Timing Systems

Traditional signal controllers use fixed timing plans, unable to adapt to sudden traffic flows. By connecting inductive loop detectors and signal controllers via serial to Ethernet converters, dynamic timing based on real-time vehicle flow can be achieved. For example, when northbound vehicle density exceeds a threshold, the system completes the following operations within 80ms:

• Inductive loop detectors report data via RS485.
• The USR-TCP232-410s converts Modbus RTU protocol to TCP/IP.
• The control center algorithm calculates a new timing plan.
• Instructions are sent back to the signal controller via the serial to Ethernet converter.
  Actual testing in Guangzhou's Tianhe City commercial district showed that this system improved intersection capacity by 22% and reduced average delay time by 18%.

3.2 Priority Passage for Emergency Vehicles

Fire trucks, ambulances, and other special vehicles need to pass intersections quickly. By connecting RFID identification devices and signal controllers via serial to Ethernet converters, "green wave" bands can be automatically activated:

• Vehicles pass through RFID readers (5.8GHz band).
• The readers send vehicle information to the serial to Ethernet converter via RS232.
• The server parses license plate types and triggers priority passage instructions.
• The signal controller adjusts to all-green status within 300ms.
  In a pilot project in Beijing's Chaoyang District, the average time for emergency vehicles to pass intersections was reduced from 45 seconds to 12 seconds.

3.3 Multi-System Collaborative Control

Smart traffic requires integration of multiple subsystems such as signal control, video surveillance, and weather warnings. The MQTT protocol support of the USR-TCP232-410s enables "dialogue" between devices:

• When a weather station reports a rainstorm warning via a 4G module.
• The serial to Ethernet converter pushes JSON-formatted warning information to the signal control system.
• The system automatically extends pedestrian crossing time and adjusts vehicle timing.
  Projects in Shanghai's Pudong New Area showed that this collaborative mechanism reduced rainy-day traffic accident rates by 31%.

4. Technological Evolution and Future Trends

4.1 Integration of 5G and Edge Computing

With the commercialization of 5G, serial to Ethernet converters are evolving from "protocol converters" to "edge computing nodes." The USR-TCP232-410s already supports edge collection functions, enabling local completion of:

• Vehicle trajectory prediction (based on LSTM neural networks).
• Accident risk assessment (combining vehicle speed and spacing data).
• Pre-calculation of signal timing.
  In a pilot project in Shenzhen's Qianhai Free Trade Zone, edge computing improved system response speed to the 5ms level, meeting vehicle-road coordination requirements.

4.2 Comprehensive Security Upgrades

Traffic data involves public safety and must meet Class III requirements of the Cybersecurity Classification Protection 2.0 standard. The USR-TCP232-410s provides:

• SSL/TLS 1.3 encrypted transmission.
• Support for Chinese national cryptographic algorithms SM2/SM4.
• Device identity authentication (based on X.509 certificates).
  In Zhengzhou's smart traffic project, this security mechanism successfully resisted 120,000 network attacks per day, reducing data leakage risks to zero.

5. Consulting and Customized Solution Services

5.1 One-Stop Support from a Professional Team

We have a 20-member expert team in the traffic field, with members from Huawei, Hikvision, and other enterprises, averaging over 8 years of project experience. Services provided include:

• On-site surveys and requirement analysis.
• Customized configuration of serial to Ethernet converters.
• Protocol docking and system joint debugging.
• 7×24-hour remote operation and maintenance.

5.2 Typical Solution Case Library

We have successfully delivered 327 traffic projects, covering:

• Expressway network control in megacities (e.g., Beijing's 5th Ring Road).
• Traffic疏导 in tourist city scenic areas (e.g., Sanya's Yalong Bay).
• Optimization of freight corridors in industrial parks (e.g., Suzhou Industrial Park).

5.3 Rapid Response Mechanism

After contacting us, we will reply within 2 hours, providing on-site deployment, one-on-one technical support, and worry-free after-sales service. For urgent projects, we can initiate a "72-hour rapid deployment" process to ensure systems go live on schedule.

Initiate a New Era of Intelligent Traffic Signal Control

When serial to Ethernet converters weave scattered traffic devices into a real-time responsive neural network, urban traffic is transitioning from "passive adaptation" to "active optimization." As a carrier of this transformation, the USR-TCP232-410s provides a solid technical foundation for smart traffic construction with its industrial-grade reliability, protocol compatibility, and edge computing capabilities.

Contact us to obtain customized solutions tailored to your city's traffic scenarios, making every traffic signal a smart node in the city's flowing landscape.