Control device for a multi-voltage on-board electrical system of a vehicle, wherein the multi-voltage on-board electrical system comprises a first subsystem configured to be operated with a first supply voltage from a first voltage supply source, and a second subsystem configured to be operated with a second supply voltage from a second voltage supply source; the control device comprising: - a transceiver, which is connected to earth via a first earth terminal of the first subsystem and which is configured for communicating with a communication component of the first subsystem; - a control unit, which is connected to the same earth via a second earth terminal of the second subsystem and which is configured for controlling a power component (322, 323) of the second subsystem; - a transmission path, which couples a signal output of the control unit to a signal input of the transceiver, wherein the transmission path is configured for transmitting a control signal provided by the control unit at the signal output towards the signal input of the transceiver; - a diode arranged in the transmission path, the cathode terminal of said diode being coupled to the second earth terminal; and - a number of at least two field effect transistors (132, 133), wherein the number of field effect transistors (132, 133) comprises a first field effect transistor arranged in the transmission path, said first field effect transistor having a first signal terminal coupled to the first voltage supply source and a second signal terminal coupled to the signal input of the transceiver, and the number of field effect transistors (132, 133) has a second field effect transistor arranged in the transmission path, said second field effect transistor having: - a first signal terminal coupled to the cathode terminal of the diode; - a second signal terminal coupled to the second earth terminal; - a control terminal coupled to the signal output of the control unit, wherein an anode terminal of the diode is coupled to a control terminal of the first field effect transistor, and wherein the second supply voltage is greater than the first supply voltage. - a transceiver, which is connected to earth via a first earth terminal of the first subsystem and which is configured for communicating with a communication component of the first subsystem; - a control unit, which is connected to the same earth via a second earth terminal of the second subsystem and which is configured for controlling a power component (322, 323) of the second subsystem; - a transmission path, which couples a signal output of the control unit to a signal input of the transceiver, wherein the transmission path is configured for transmitting a control signal provided by the control unit at the signal output towards the signal input of the transceiver; - a diode arranged in the transmission path, the cathode terminal of said diode being coupled to the second earth terminal; and - a number of at least two field effect transistors (132, 133), wherein the number of field effect transistors (132, 133) comprises a first field effect transistor arranged in the transmission path, said first field effect transistor having a first signal terminal coupled to the first voltage supply source and a second signal terminal coupled to the signal input of the transceiver, and the number of field effect transistors (132, 133) has a second field effect transistor arranged in the transmission path, said second field effect transistor having: - a first signal terminal coupled to the cathode terminal of the diode; - a second signal terminal coupled to the second earth terminal; - a control terminal coupled to the signal output of the control unit, wherein an anode terminal of the diode is coupled to a control terminal of the first field effect transistor, and wherein the second supply voltage is greater than the first supply voltage.