Skip to content 
GNX Protocol Technical Integration Master Guide
Complete Reference: GNX-2 & GNX-3 Hardware | Port 5106 | 12V-24V Systems
The GNX Protocol is a high-performance communication standard designed for mission-critical telematics and fleet management. Engineered for stability and data efficiency, devices such as the GNX-2 and GNX-3 utilize this protocol to deliver high-frequency location updates, precise sensor telemetry, and advanced engine diagnostics over TCP Port 5106.
This guide serves as a comprehensive technical resource for hardware installers and system integrators. It covers everything from standard 12-pin harness configurations for light vehicles to complex 24V relay setups and CAN-Bus integration for heavy-duty logistics. By following these standardized wiring and SMS configuration protocols, you ensure seamless connectivity, accurate ignition detection, and robust remote immobilization capabilities for any asset in your fleet.
1. Device Comparison & Core Specs
| Feature | GNX-2 Model | GNX-3 Model |
|---|---|---|
| Protocol / Port | GNX / 5106 | GNX / 5106 |
| Target Vehicles | Light Vehicles / Bikes | Heavy Trucks / CAN-Bus Fleet |
| Voltage Range | 8V – 32V DC | 8V – 36V DC |
| Internal Memory | Up to 8,000 points | Up to 16,000 points |
2. Advanced Wiring & Relay Diagrams
Standard 12-Pin Harness (GNX-3)
| Pin | Color | Function | Note |
|---|---|---|---|
| 1 | Red | Power (+) | Constant 12V/24V |
| 3 | Black | Ground (-) | Chassis GND |
| 7 | White | Ignition | ACC Signal |
| 8 | Yellow | Relay Ctrl | Output (-) 300mA |
Heavy Duty 24V Relay Installation (Trucks)
Important: For 24V trucks, you MUST use a 24V DC Relay. Using a 12V relay will cause immediate component failure.
- Relay Pin 85: Connect to GNX-3 Yellow Wire (Output).
- Relay Pin 86: Connect to 24V Constant Power.
- Relay Pin 30: Connect to the supply side of the cut fuel pump/starter wire.
- Relay Pin 87a: Connect to the engine side of the cut wire.
CAN-Bus Integration (GNX-3 Advanced)
GNX-3 supports FMS/CAN-Bus reading via external adapters or direct pins (depending on sub-version):
- CAN High (Yellow/White): Connect to Vehicle CAN-H (usually Pin 6 on OBDII).
- CAN Low (Blue/White): Connect to Vehicle CAN-L (usually Pin 14 on OBDII).
- Command to enable CAN: Send canbus123456 on via SMS.
3. Comprehensive SMS Configuration
| Target Setting | SMS Command Syntax | Response |
|---|---|---|
| Set Server/Port | adminip123456 185.123.45.67 5106 | adminip ok |
| Set APN | apn123456 internet | apn ok |
| Angle Upload | angle123456 30 | Set upload on 30° turn |
| Cut Fuel | stopoil123456 | stop oil ok |
| Reboot Unit | reset123456 | System Resetting… |
4. Technical Troubleshooting Checklist
- No Data on Port 5106: Use a tool like Hercules or Packet Sender to confirm your server’s port 5106 is open to TCP traffic.
- Ignition Not Detected: Ensure the White wire is connected to a source that only has 12V/24V when the key is in the “ON” position.
- CAN-Bus Data Missing: Ensure the baud rate matches the vehicle (usually 250kbps or 500kbps). Send canrate123456 500.
- Device “Sleeping”: If the device goes offline when parked, check the sleep settings: sleep123456 off.
