PORTABLE TELEPHONE SYSTEM AND ITS OPERATING METHOD

摘要

PROBLEM TO BE SOLVED: To prevent excessive volume in a speakerphone mode from being heard by a user in a portable telephone which is operated in the speakerphone mode. SOLUTION: When the user performs the request operation of the speakerphone mode to a user interface 102 and it is detected that the portable telephone 100 is in a horizontal state in this case by an inclination sensor 108, the mode is made to be the speakerphone mode. Since the portable telephone 100 cannot be put on the ear of the user when it is in the horizontal state, excessive volume is not heard by the user even in the speakerphone mode.