Mobile phone has been penetrated widely beyond generations and now that it is becoming a must also for middle-aged and senior people. It is not only used as an important communication tool for a voice call but also for Short Message Service (e-mail). As a result, there emerged demands for easy-to-read display and simpler key entry. J-PHONE (Existing Softbank Mobile) developed "Simple Phone" targeting the middle-aged and senior generation with "T9" entry system, which is the most widely spread system overseas. We conducted a comparative experiment to verify its operability against the normal entry system.