Telephone apparatus, method of controlling telephone apparatus, and program

A method of controlling a telephone apparatus

• comprising
• performing, by a control unit of the telephone apparatus, a first processing of:
• estimating a line echo amount based on
• a volume of a DTMF signal generated based on a telephone number and
• a volume of the DTMF signal input from a line;
• calculating a howling noise threshold value based on
• a maximum value of an acoustic echo generated at a handset and
• set values of a volume of a sidetone signal, a volume of a transmission signal, and a volume of a reception signal;
• and
• calculating a difference between the line echo amount and the howling noise threshold value as an adjustment requisite amount and
• lowering the set value of the volume of the sidetone signal by the adjustment requisite amount
• when the line echo amount is larger than the howling noise threshold value.

A non-transitory computer readable medium storing a program for a causing

• a control unit of a telephone apparatus to perform a first processing of:
• estimating a line echo amount based on
• a volume of a DTMF signal generated based on a telephone number and
• a volume of the DTMF signal input from a line;
• calculating a howling noise threshold value based on
• a maximum value of an acoustic echo generated at a handset and
• set values of a volume of a sidetone signal, a volume of a transmission signal, and a volume of a reception signal;
• and
• calculating a difference between the line echo amount and the howling noise threshold value as an adjustment requisite amount and
• lowering the set value of the volume of the sidetone signal by the adjustment requisite amount
• when the line echo amount is larger than the howling noise threshold value.