Popular utilities like , ModSim64 , or Modbus Slave (from ModbusTools) are commercial software products. While developers offer free trial versions for testing, these trials come with deliberate operational limits to encourage users to purchase a license. Limitations of Unregistered/Trial Software
(also called a Unit ID or Device Address) rather than a digital key. Control.com Modbus RTU Slave. Define register addresses - Arduino Forum modbus slave registration key
While there is no singular academic paper dedicated solely to "The Modbus Slave Registration Key," the mechanism is analyzed in broader SCADA security research regarding Modbus TCP Gateways . Popular utilities like , ModSim64 , or Modbus