An input/output (I/O) and control system for long distance communications and industrial applications having a bus and protocol for communications between field devices and a channel generator for monitoring and control of the field devices. The channel generator produces an offset square wave of configurable frequency on the bus, and sends a synchronization pulse of selected duration at the start of each bus scan cycle in a pulse train cycle to reset counters in the field devices before the bus scan cycle is repeated, to ensure field devices are synchronized, transmitters transmit on the correct channel, and receivers sample the pulse cycle at the correct time. Changing the synchronization pulse length increases bandwidtli for shorter, less noisy and more stable systems and inversely decreases bandwidth for increased noise immunity and distance for longer, noisier and less stable systems.
