Communication system, communication terminal apparatus and wireless key apparatus

摘要

It is constituted such that a function limitation is to be applied to a communication terminal apparatus of a mobile telephone terminal or the like at a place far from wireless key by a constant distance and it is also constituted such that after the function limitation is applied once, it is made impossible for the function limitation to be released until the communication terminal. The transmission power is controlled in response to the state by utilizing a phenomenon that the communication possible distance between the apparatuses changes according to the amount of the transmission power wireless-communicated. Specifically, with respect to the transmission power on the occasion when a connection operation is carried out between the communication terminal apparatus and the wireless key, it is constituted for the transmission power from at least one of apparatuses such that the transmission power when releasing the function limitation is made smaller than the transmission power when applying the function limitation. Further, after the function limitation is released, the transmission power is again increased to the original transmission power when applying the function limitation.