A system and a method are for routing data packets from or to at least one electronic control unit, referred to as outgoing packets or incoming packets respectively. The at least one electronic control unit is connected to a communications system via a first interface. The communications system is connected via a second interface to a modem suitable for transferring the outgoing packets and the incoming packets to or respectively from at least one telecommunications network through a plurality of access points. Each access point is secured or unsecured. The outgoing and incoming packets are processed according to the type of access point by which the packets are transferred to or from the at least one telecommunications network.