A control system has a first module that includes a memory and diagnostic logic. A user equipment 100 has a memory unit 102 which stores service class information showing correspondence between service classes indicative of available communication services, and service class codes to discriminate the service classes. The radiator is formed from radiating fins and is provided at a top thereof with a receiving recess for receiving the pressure-bearing unit therein. From the wet tank the air passes through a conduit through the air dryer to the dry tank. The frame has a plurality of engagement segments which are spaced-apart longitudinally and transversely when the filter body is in the deployed expanded configuration to urge the filter body into opposition with the vessel wall. The method has been found to have particular utility in estimating residual fuel and insolubles contamination in marine diesel lubricating oils.