====== How to choose dtmf mode ====== ===== What is DTMF ===== DTMF (dual tone multi frequency) is the signal to the phone company that you generate when you press an ordinary telephone's touch keys. ===== What's DTMF for ===== Without correct DTMF, a IVR could not understand what's customer input. ===== 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> {{:en:faq: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