Figure 13: With bus topology every module has to be connected directly to the BUS or line. (Illustration source: E&D Systems)
The bus cable here goes from module to module. A branch connected to a number of modules is not allowed. The bus cable starts from one module, goes to the next module, and then on to the next until it is finally connected to the last module. In practice, a terminating resistor has to be put on the bus at the start and at the end to stop reflections on the bus.