Pump | Gilbarco Dispenser Two-wire Protocol For Third Party

The core transaction for authorizing a fuel sale is elegant:

The Two-Wire Protocol emerged during the early days of electronic dispensers, a time when microprocessors were expensive and communication standards like RS-232 or Ethernet were not yet ubiquitous in industrial environments. Gilbarco designed a system that required only a single twisted pair of copper wires to carry both power and data between the dispenser and a control box (often the POS system’s pump interface card). This design minimized installation costs and complexity, a critical advantage for gas stations with multiple dispensers spread across a concrete island. Gilbarco Dispenser Two-wire Protocol For Third Party Pump

[ Third-Party Forecourt Controller ] │ (RS-232 / RS-485) ▼ [ Interface Converter / D-Box ] (45mA Current Loop Active Driver) ▲ ▲ 2-Wire │ │ 2-Wire Loop 1 ▼ Loop 16 ▼ [ Dispenser 1 ] ... [ Dispenser 16 ] The 45mA Current Loop The core transaction for authorizing a fuel sale