Modbus communication can be debugged using serial port debugging tools or commonly used Modbus debugging tools, such as ModScan, Modbus Poll, and Modbus Slave. ModScan and Modbus Poll simulate Modbus RTU or Modbus TCP clients, while Modbus Slave simulates Modbus RTU or Modbus TCP servers. The three tools are third-party software that can be purchased on their websites or downloaded for a trial period.