Problems: Motion control for high-speed conveyors, such as OHTs and sorters, can be performed with mechanical flags that use photoelectric sensors and optical communications devices. With systems based on mechanical flags, however, position displacement caused by shocks and vibration can result in malfunctions. Wear-and-tear can lead to problems related to light-source deterioration, and malfunctions due to dirt can occur. In order to develop a faster system, a greater level of autonomy is needed. RFID technology would give the required level of autonomy but, generally speaking, the communications speed would be too slow. Mount ID Tags to the OHTs and install Antennas at stations and junctions as required. Store OHT unit numbers and other relevant information in the ID Tags. When an OHT reaches a station, read the unit number with the Antenna, and send the OHT to the specified location by switching points as necessary via the control system (e.g., PLC) connected to the Antenna.