Workstation takeover control

Abstract

Workstations are connected via workstation controllers to two computer systems where one of the workstation controllers is a primary or controlling workstation controller and the other workstation controller is connected to appear to the primary workstation controller as a workstation and is designated as the secondary or standby workstation controller. The standby workstation controller has its line impedance matching resistor connected to function as a line terminator but it can also function as a line driver resistor when the primary or controlling workstation controller fails, the failure of the primary or controlling workstation controller being detected by the secondary or standby workstation controller upon the failure of being polled by the primary or controlling workstation controller within a predetermined period of time. The line impedance matching resistor of the failing primary or controlling workstation controller then functions as a line terminator resistor. The primary or controlling workstation controller and the secondary or standby workstation controller are connected backwards with respect to the connection of workstation to workstation whereby the line impedance matching resistor of the workstation adjacent to the filing primary or controlling workstation controller can function as a line terminating resistor to permit the failing workstation controller to be removed from the system for repair without creating a line termination problem for the workstations and the standby workstation controller which has become the controlling workstation controller.