1. A method of remote control by a user of a gateway that forms a bridge between different data networks, said gateway converting received data from one data network protocol to another, the method comprising the steps of: storing, within the gateway, one or more commands which may be invoked remotely by the user, said commands causing a data exchange between the gateway and a remote system connected to one of the data networks; transmitting via one of the data networks at least one data packet from data terminal equipment operated by the user to the gateway, wherein at least one data packet includes control data containing information directing the gateway to execute one or more commands on behalf of the user; validating that each of the one or more commands to be executed on behalf of the user is stored within the gateway; and executing each command that is validated in the validating step.