This official guide covers the serial-line architecture used for Modbus RTU and ASCII networks, including framing, timing, addressing, master–slave behaviour and physical-layer implementation considerations.
It is particularly useful when designing RS-485 networks, selecting termination and bias arrangements, diagnosing intermittent communication or confirming conformance for a new device.
This reference is maintained by Modbus Organization. Use the official source for the latest revision and licence terms.
