For exact level balancing or signal-to-noise ratio balancing of received signals in a wave-length-division multiplex transmission system, the associated transmitted signal power levels are adjusted. The potential of the supporting member is controlled to not be higher than the maximum potential applied to the electron-emitting element. A battery is provided which is initially coupled to the tag circuitry by a connector means which allows non-destructive removal and replacement of the battery. A real-time, interactive connection is established between A and B which takes a certain delay time. In yet another embodiment, an arcuate device is used to remove the entire intervertebral disc and place supports to maintain a disc space. The tablet filling device includes: a detachable tablet feeding unit including a plurality of tablet feeders capable of discharging tablets one by one and arranged horizontally and vertically; and an arm unit that carries an empty vial, fills the vial with tablets discharged from a tablet feeder of the tablet feeding unit, and carries the vial filled with the tablets.