The invention relates to a method of managing a call through a telecommunications network between an access terminal connected to the network and means for providing a service through the network. A memory area secured in a disk unit is used in circulation thereby to record the time series input data. A rotating mechanism is provided for mounting, rotating, and pulling up a seed rod for forming the porous optical fiber preform. The radiation scanning inspection device may be switched between higher and lower positions as required with the ascendingdescending of its combination with the lifting device.