The CTC products use PLC4TRUCKS which stands for Power Line Carrier. Communication is done using the existing power wire on the J-560 connector used for electrical connections. Using the SAE J-2497 protocol, the CTC can transmit information back and forth between the cab and trailer. This includes lift axle control and status messages, ABS warning lights, reverse lights, and many more. The CTC 200 and 400 differ in the number of inputs and outputs they provide.