| 摘要 |
PROBLEM TO BE SOLVED: To obtain an electronic volume device which enables a user to adjust the sound volume of a ringer with high operability at the time of adjustment. SOLUTION: An electronic volume for ringer sound adjustment which is used in a telephone terminal device, which reports incoming calls by ringer sound, and adjusts the volume by continuous depression of volume adjustment keys 10a and 11a is constituted of a control means 4A which performs control to execute the volume adjustment synchronously with the sounding period of the ringer for the operation period of volume adjustment keys at the time of operating the volume adjustment keys.
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