Abstract: A digital transmission system for replacing complex, many-wire, analog system in transportation and construction vehicles includes a uni-directional or bi-directional signal bus structure and a optional power bus structure. The signal bus structure is composed of uni-directional or bi-directional signal carriers. Uni-directional or bi-directional signal tap lines attach to the signal bus with terminal devices. The signal bus and tap lines terminate in microprocessor devices that generate, prioritize, send, receive, and process signals that are sent through the signal bus and its tap lines. Electro-mechanical, electrical, and electronic devices attach either directly or through converters to the terminating microprocessors. When any terminal device is operated or otherwise generates information, the microprocessor to which the device is attached generates a signal identifying the device and prioritizing and coding the information that is generated.