Professional 4G GPS Tracker FMC125 with RS232, RS485 and dual SIM

RS232 + RS485 + dual SIM. The Professional model for fleets that need external peripherals and roaming redundancy.

The FMC125 is the most advanced model in Teltonika's Professional range. It keeps the format of the FMC120 family but adds two key features for demanding fleets: serial peripheral support (RS232 + RS485) and dual SIM with automatic switching between two carriers.

RS232 + RS485 enable connection of external sensors that the standard digital inputs cannot read: fuel level probes, ultrasonic tank sensors, refrigerator units (FrigoBlock, Carrier, Thermo King), barcode/RFID readers, on-board printers, weighing scales. The serial peripheral catalogue compatible with Teltonika is huge — anything that speaks RS232 or RS485 standard can be integrated.

Dual SIM is critical for fleets that cross borders or operate in areas with patchy coverage: you put a primary SIM (e.g., Movistar Spain) and a secondary one (Vodafone Europe, Telnyx M2M, EMnify) and the FMC125 switches automatically when the primary signal drops. Zero data loss in transition.

Stock in Spain, delivery in 3-5 working days. The benchmark for international hauliers, cold-chain distribution and any fleet needing additional connected sensors.

Key features

• 4G LTE Cat 1 + 2G fallback with European coverage
• Dual SIM with automatic switching by signal/preference
• RS232 interface for serial peripherals (fuel sensors, refrigerator units, printers)
• RS485 interface for industrial sensors (Modbus, J1708)
• 4 digital inputs + 4 digital outputs (largest in its range)
• Bluetooth 4.0 for iButton and EYE sensors
• 170mAh internal backup battery
• Compatible with CAN-CONTROL for OEM data

Use cases

1. International haulier with 8 trucks crossing ES-FR-DE — FMC125 with dual SIM (Movistar primary + Vodafone Europe roaming) guarantees seamless coverage and avoids roaming surcharges over a year.
2. Cold-chain distribution with 15 refrigerated vans — FMC125 + RS232 connected to FrigoBlock reads compartment temperature in real time, triggers alerts if it goes out of range and stores history for HACCP audit.
3. Heavy fuel transport with 12 tankers — FMC125 + RS485 connected to a magnetostrictive level probe reads volume in cubic metres with industrial precision, detects unauthorised draining or refuelling.

The advanced option for fleets that need more than basic tracking. Stock in Spain, technical support in EN/ES.

Related technical documentation

• Which model do I need? — selector by use case (light vehicle / truck / asset / motorbike / construction).
• FOTA · Remote firmware update — how to manage device firmware remotely from the Teltonika console.
• Codec 8 / 8E / 16 protocol — binary reference, tested integrations (Traccar, Wialon, Flespi, Fleet Complete) and notes for custom parsers.
• Warranty and RMA process — 3-year legal cover + 24-month Teltonika commercial warranty.