: Constantly polling the dispenser to determine the current state (e.g., Idle, Nozzle Lifted, Fueling, Transaction Complete). Data Retrieval
The protocol is not standard RS-232. It utilizes a interface (typically 20mA or 40mA active/passive) or a proprietary differential signaling method.
Despite the exotic physical layer, the underlying data transmission relies on standard Universal Asynchronous Receiver-Transmitter (UART) framing: : Constantly polling the dispenser to determine the
: Professional-grade interfaces like the Levtech LSP-FCG
For a new third-party controller to successfully operate Gilbarco dispensers via the Two-Wire Protocol, the following integration points must be addressed: Despite the exotic physical layer, the underlying data
A 1-byte checksum calculated by XORing all bytes from the Address through the ETX. 4. Core Protocol Command Set
| Manufacturer | Product | Notes | |--------------|---------|-------| | FMS (Fuel Management Systems) | FMS 3000 | Fleet keypad, two-wire native | | Syntech Systems | FMS-PRO | Supports two-wire + RS-485 | | Raytec | RC-200 | Retrofit for car washes | | Wayne (Dover) | iX Pay | Limited two-wire legacy mode | | Verifone | Commander (with serial adapter) | Via Gilbarco’s “G-SITE” adapter | | | Intermittent drops | Ensure total loop
| Issue | Resolution | | :--- | :--- | | | Check current loop polarity – swap A/B wires. | | Intermittent drops | Ensure total loop resistance < 500Ω. Add terminator (120Ω) only at last dispenser. | | Parity errors | Third-party controller must use Even parity – not none, odd, or mark/space. | | Handle drops | Dispenser requires polling every 100-200ms; long gaps cause auto-cancel. |
: Communication is achieved via a 20mA or 45mA current loop. Third-party controllers usually require a hardware interface or "D-Box" (Distribution Box) to convert standard serial signals (RS-232 or RS-485) into the specific current loop required by the dispenser. Data Parameters : Typical settings vary by dispenser model: Legacy (Highline-2, Euroline) : 4800 baud, 8 data bits, Even parity, 1 stop bit. Modern (Encore, SK700) : Often referred to as "Corporate baudrate" at , 8 data bits, Even parity, 1 stop bit. Data Format
Use Gilbarco’s IDX (Intelligent Dispenser Interface) or TLS-450 serial gateway, which converts two-wire to modern protocols (TCP/IP, MQTT) without dealing with current-loop hardware.
The volume delivered is calculated based on pulse counts.