Gilbarco Dispenser Twowire Protocol For Third Party Pump Controllers New Jun 2026

Ensure the polling engine can seamlessly manage a fully loaded loop of 16 simultaneous fueling positions without dropping packets. To help optimize your implementation, please let me know:

: Releasing the pump for a transaction after a user has been verified or a payment pre-authorized. Preset Management

Packets include a Longitudinal Redundancy Check (LRC) to ensure data hasn't been corrupted by forecourt interference. Key Functional Commands for Controllers

Standard PCs or microcontrollers cannot talk "Two-Wire" directly. You require a specialized level converter or a "Distribution Box" (D-Box) to bridge the gap between TTL/RS-232 logic and the 45mA loop. Why Two-Wire Still Dominates Ensure the polling engine can seamlessly manage a

The two-wire protocol returns pulses as a frequency. The new converters output these as standard quadrature encoder pulses or Modbus registers. Your third-party pump controller can now read with sub-penny accuracy.

Fuel retailers use dispensers from various manufacturers, and often, these dispensers need to communicate with pump controllers from different vendors. The lack of a standardized communication protocol has led to compatibility issues, increased costs, and complexity in system integration. To address this challenge, Gilbarco has developed a two-wire protocol that enables seamless communication between Gilbarco dispensers and third-party pump controllers.

Unlike standard RS-232 or RS-485, the Gilbarco protocol traditionally operates on a 2-wire current loop Levtech Service & Production Key Functional Commands for Controllers Standard PCs or

| Command (Hex) | Function | Response Length | Example Use | |---------------|-----------|----------------|--------------| | 0x30 | Request fuel authorization | 2 bytes (status + volume) | Start pump | | 0x31 | Read totalizer volume | 4 bytes BCD | Volume reconciliation | | 0x32 | Read price per unit | 3 bytes BCD | Display price | | 0x33 | Read status (in use/ idle/ error) | 1 byte | Polling | | 0x35 | Disable dispenser | 1 byte ack | Remote lockout | | 0x36 | Enable dispenser | 1 byte ack | After payment approved |

Gilbarco proprietary systems send a "Resettle" command every 60 seconds to clear hanging transactions. Third-party controllers often forget this.

To manage this, a is almost always required. This device sits between the third-party controller and the Gilbarco dispenser, converting the PC's standard RS-232 or USB signals into the 20mA current loop signals that the dispenser understands. Many modern interfaces feature a USB port and appear as a Virtual Serial COM Port to the host system, making them compatible with microcomputers like a Raspberry Pi for custom integration projects. The new converters output these as standard quadrature

For the last ten years, the common advice for third-party integrators was: "Install a Gilbarco Pass-Through box or replace the dispensers." That advice is now outdated. Several factors have converged to create a environment for third-party pump controllers using the two-wire protocol.

While the physical layer uses current loops, the data layer utilizes standard asynchronous serial parameters. Third-party controllers must configure their UART peripherals to the following strict specifications:

Dispenser fault detected (e.g., pulser error, blend failure). 2. Authorization Command

Dynamically changing the price per gallon/liter displayed on the dispenser head. Implementation Challenges for New Developers

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