Communication device (10; 20) including two electronic control units (100, 200) that each include a first electric terminal (101, 201), a second electric terminal (102, 202), and a communication terminal (103, 203) connected to the communication terminal (103, 203) of the other electronic control unit (100, 200) by a communication wire, in which: - a first electronic control unit of said two electronic control units comprises a power supply terminal (SUPP) supplied at a first supply voltage and connected to an electrical distribution unit to deliver on its first electric terminal a first reference voltage level (V SUPP), a ground terminal supplied at a first ground voltage and connected to a ground bolt situated as close as possible to the first unit to the first electronic control unit so as to deliver on its second electric terminal a second reference voltage level (V GND), and a generation means suitable for emitting a voltage signal (SLIN) referenced to said reference voltages (V SUPP, V GND) on its communication terminal, and - a second electronic control unit of said two electronic control units includes a means for processing said voltage signal (SLIN) received on its communication terminal via said communication wire, - two reference wires (11, 12) connecting said first electric terminals (101, 201) to each other and said second electric terminals (102, 202) to each other, and - a guide means routes said reference wires (11, 12) with said communication wire between said two electronic control units (100, 200), characterized in that: - the second electronic control unit comprises a power supply terminal supplied at another supply voltage and a ground terminal supplied at another ground voltage, and in that - the first electronic control unit comprises disconnection means adapted to disconnect its first electric terminal from the first supply voltage and its second electric terminal from the first ground voltage when sending a voltage signal (SLIN) from the second electronic control unit to the first electronic control unit, and in that - the second electronic control unit comprises disconnection means adapted to connect its first electric terminal to the other supply voltage and its second electric terminal to the other ground voltage when sending a voltage signal (SLIN) from the second electronic control unit to the first electronic control unit. - a first electronic control unit of said two electronic control units comprises a power supply terminal (SUPP) supplied at a first supply voltage and connected to an electrical distribution unit to deliver on its first electric terminal a first reference voltage level (V SUPP), a ground terminal supplied at a first ground voltage and connected to a ground bolt situated as close as possible to the first unit to the first electronic control unit so as to deliver on its second electric terminal a second reference voltage level (V GND), and a generation means suitable for emitting a voltage signal (SLIN) referenced to said reference voltages (V SUPP, V GND) on its communication terminal, and - a second electronic control unit of said two electronic control units includes a means for processing said voltage signal (SLIN) received on its communication terminal via said communication wire, - two reference wires (11, 12) connecting said first electric terminals (101, 201) to each other and said second electric terminals (102, 202) to each other, and - a guide means routes said reference wires (11, 12) with said communication wire between said two electronic control units (100, 200), - the second electronic control unit comprises a power supply terminal supplied at another supply voltage and a ground terminal supplied at another ground voltage, and in that - the first electronic control unit comprises disconnection means adapted to disconnect its first electric terminal from the first supply voltage and its second electric terminal from the first ground voltage when sending a voltage signal (SLIN) from the second electronic control unit to the first electronic control unit, and in that - the second electronic control unit comprises disconnection means adapted to connect its first electric terminal to the other supply voltage and its second electric terminal to the other ground voltage when sending a voltage signal (SLIN) from the second electronic control unit to the first electronic control unit.