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====== How to choose dtmf mode ====== ===== What is DTMF ===== 双音多频 DTMF（Dual Tone Multi Frequency），双音多频，由高频群和低频群组成，高低频群各包含4个频率。一个高频信号和一个低频信号叠加组成一个组合信号，代表一个数字。DTMF信号有16个编码。利用DTMF信令可选择呼叫相应的对讲机。 ===== dtmf在系统中的作用 ===== 通俗的讲，系统会将用户输入转换成dtmf信号发送出去，当dtmf出现问题时，往往一般表现为用户无法通过按键在语音菜单(IVR)中做出选择。 ===== Set DTMF ===== Usually we just need to make sure it's using correct dtmfmode in the trunk. The option is dtmfmode= the options are * auto * inband * info * rfc2833 For example <code> dtmfmode=rfc2833 </code> {{:zh:常见问题及解答:dtmfmode.png?768|}} <note tip>In the default template, astercc is using rfc2833</note> ===== How to config DTMF ===== * For inbound/outbound, you need to make sure you configured correct dtmfmode same as your provider asked, in most case, use rfc2833 * When you are using inband, the codec need to be ulaw or alaw