Abstract: A secure processing facility has a plurality of workstations, with associated computers to provide data to, and/or receive data from, the workstations. The computers are provided with a visual display unit, and display machine-readable data codes on the display. The computers are provided with a scanner to read the machine-readable data codes on the display of another of the computers. The computers have no other connection to receive or transmit machine readable data. A method of operating the facility includes processing a workpiece at a first workstation. A display of the computer of the first workstation displays a data code containing data related to the processing of the workpiece. The scanner of the computer associated with a second workstation scans the data code. The workpiece is transferred from the first workstation to the second workstation. The workpiece is processed at the second workstation.