Patent attributes
A communication system including a communication terminal apparatus and a wireless key apparatus in wireless communication is provided. The communication terminal apparatus includes a first communication unit operable to receive a first wireless signal, and a first control unit operable to determine a distance between the communication terminal apparatus and the wireless key apparatus based on the received first wireless signal, wherein the first control unit limits a predetermined function of the communication terminal apparatus based on determining the distance. The wireless key apparatus includes a second communication unit operable to receive a second wireless signal, and a second control unit operable to determine the distance between the communication terminal apparatus and the wireless key apparatus based on the received second wireless signal, whereby the second control unit decreases transmission power associated with the second communication unit based on the determined distance.
