There is provided a system and method of audio-video communications including a plurality of end-user terminals coupled via a communications link. The invention is characterized in that a lubricant sump in a housing of the steam engine is heated to a temperature above the evaporating temperature of the working medium by means of a heating device during the starting phase of the steam engine. Rotation of the nozzle about its axis changes the alignment of the axis of the nozzle relative to the axis of the mounting tube. An interlayer insulating film is provided on the gate electrode such that the conductor portion is electrically insulated from the gate electrode. Then, the replacement loaner parts are automatically shipped to the customer to replace the expiring loaner parts to prevent callback of the selected loaner system.