In case of a loss of power supply a short-circuit between the corresponding pins of the two IEEE 1394 connectors of a device is established. Preferably this will be achieved by a relay controlling switches. If power is available, the relay is powered and the switches are open. The device then behaves like without this extension. If power is lost, the relay is not powered any longer, and the switches are closed. By this way, the device simply disappears from the cluster, which will then be reorganised according to IEEE 1394 rules.