Abstract: A modular expandable gateway has at least one base module, including a broad-band data communication device for handling communications with an external broad band data communication network, at least one local network port for the connection to a local communication network, a local network interface device adapted to handle communications with the local data communication network and coupled to the local network port through a local network communication bus, the local network interface having a media independent interface and a disable input, a data processing unit interacting with the broad-band data communication device and, through a media independent interface bus connected to the media independent interface, with the local network interface device, so as to enable intercommunication between the local network and the external network; a disable signal line coupled to the disable input of the local network interface device and adapted to drive the local network interface device into a disabled state in