Patent ID: 7283479

Claim:
A communication system comprising: a plurality of local networks; a head end connected to the local networks, wherein signals are transmittable from the local networks to the head end within a predetermined carrier frequency band; and a monitor arrangement configured to monitor disturbances within the carrier frequency band, the monitor arrangement including: a detector arrangement within each local network, each detector arrangement being configured to compare an energy level of signals occurring within the carrier frequency band with a predetermined reference level and to generate logic signals relating to the result of the comparison, a memory device within each local network, each memory device being configured to store information derived from the values of the logic signals about time intervals during which the energy level exceeds the reference level, and an element placed at the head end, the element being configured to fetch the information stored in the memory devices into the head end for evaluation at the head end; wherein the memory devices are configured to store the information about the time intervals in the form of information about the length of each individual interval; and wherein the memory devices are configured, at least in respect of certain periods of time, to store information about the time intervals in the form of statistics relating to the number of the intervals occurring during the periods.