Patent ID: 7863961

Claim:
A vehicle communication system, comprising: a transmission node which starts a signal transmission when switching from an OFF state to an ON state; a reception node connected to the transmission node and receiving the signal transmitted through a plurality of communication lines; a junction connector electrically coupled to the plurality of transmission lines and branching the signal into multiple channels; a grounding means electrically coupled to the junction connector and providing a electrical path to ground; a diode in which a direction directed from a negative-side output terminal of the transmission node to a positive-side output terminal thereof becomes a forward direction, the diode being disposed between the positive-side output terminal and the negative-side output terminal; and a Zener diode in which a direction directed from the negative-side output terminal to the positive-side output terminal becomes a forward direction, a direction from the positive-side output terminal to the negative-side output terminal becomes a reverse direction, and a Zener voltage becomes a reverse voltage when the Zener diode conducts in the reverse direction, in addition to the diode, the Zener diode being disposed between the positive-side output terminal and the negative-side output terminal, wherein the Zener voltage is set at a higher value than a normal value of a positive voltage of a transmission signal outputted from the transmission node such that a positive ringing voltage generated when the transmission node is switched from the OFF state to the ON state is restricted to be lower than the normal value of the positive voltage of the transmission signal.