A child car seat for a land vehicle comprises a support for supporting at least a part of a body of a child, the support being positionable on a vehicle seat of the land vehicle and a restraint for holding the body in position relative to the support. A data processing unit forms when in operational mode and connected to an in-vehicle data communication network in the land vehicle, a child car seat network node in the in-vehicle data communication network. The seat includes a first network connector for establishing, in cooperation with a matching second network connector, a data communication connection between the child car seat network node and the in-vehicle data communication network. The child car seat has a signal carrier connecting the data processing unit to the first network connector.