The Modbus program is loaded and configured with ROCLINK Configuration Software or ROCLINK for Windows Configuration Software. The program can be configured to emulate several Modbus protocol variations. In addition to acting as a Modbus slave, the ROC can function as a Modbus host (master) with the ability to poll Modbus slave devices. A port with Modbus Master enabled may still act as a Slave device. Either the ASCII or the RTU mode of transmission can be used.