Where Ideas and Technology Meet! LINE TRACKING DEVICE The Line Tracking Device (DTC) transmits the Energy On/Off information of the Low Voltage outputs to modem via RS-485Modbus RTU.There are 2 types, 8 channels and 12 channels. The product standard is wired and the wireless Bluetooth feature is optional. It switches to advanced automation with Smart Grid Solutions and becomes real-time, manageable with instant communication and control technologies.