Drahtloses Kommunikationssystem, tragbares Nachrichtenendgerät und drahtloses Kommunikationsgerät

摘要

A portable terminal monitors a signal level of a short-range wireless signal from a wireless communication apparatus. If the signal level drops so low that a state of connection for short-range wireless communications cannot be maintained between the two apparatuses, use of predetermined functions of the portable terminal is limited. A short-range wireless communication facility of the portable terminal and the wireless communication apparatus move into a particular operation mode if communications do not occur therebetween at least for a predetermined time period. In monitoring the signal level of the wireless signal from the wireless communication apparatus in the particular operation mode, the portable terminal reduces a response speed at which to detect a signal level change. This causes the wireless communication apparatus to delay issuing a request for an increase in transmission power, thereby reducing unevenness of the working distance at which to alert a user to the unusual distance traveled between the two apparatuses or beyond which to limit the use of some functions of the portable terminal.