An access point measures a congestion level of a transmission channel representing a collision probability between frames at a channel busy duration and transmits the congestion level to a terminal. The recovery unit is provided for at least the development unit other than the development unit that transfers the developing-agent image first in sequence among the plurality of development units. The mandibular tray carries a mandibular bite pad projecting upwardly toward an opposed maxillary occlusal surface. A \u201ckey\u201d is then set on the machine indicating that the filesregistry entries are installed. Through the use of the method and system of the present invention, significantly more accurate results can be obtained as compared to prior art test methods, and without the implementation, operating, and maintenance costs of comparable test methods.