A communication device includes an analog connector onboard a vehicle in a vehicle system that is coupled with a multiple unit (MU) cable extending through the vehicle system for communication of analog control signals. The device includes a network connector disposed onboard the first vehicle to communicatively couple with a digital communication network of the vehicle system that is separate from the MU cable. The device also includes a relay to close and conductively couple the control system of the first vehicle with the MU cable and to open to decouple a portion of the MU cable disposed onboard the first vehicle with a remainder of the MU cable that is off-board the first vehicle.