A system comprises a transmitter unit configured for mounting at a trailer connected to a tractor. The transmitter unit comprises a video input for receiving video data from one or more trailer cameras, a power input for receiving power from a power line of the trailer, and a wireless communication module for communicating with a mobile communication device. A memory is configured to store trailer information received from the wireless communication module, the trailer information uniquely identifying the trailer. A transmitter is configured to wirelessly transmit the video data. A receiver unit is configured for mounting at the tractor and comprises a receiver for wirelessly receiving the video data transmitted by the transmitter, a power input for receiving power from a power line of the tractor, and an output for outputting the received video data. The receiver unit is further configured to receive the trailer information from the transmitter unit.