电话用双音多频式按键号盘技术要求的英文

performance requirements of pushbutton dialer with dtmf

• 电话:    telephone; phone; ...
• 用:    40分钟跑完全程 run the c ...
• 双音多频:    dual-tone multifre ...
• 式:    type; style
• 按键号盘:    push-button dialli ...
• 技术:    technology; skill; ...
• 要求:    ask; demand; requi ...