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Using DTMF tones with Audio TX

As well as using Audio TX for ISDN voiceover sessions, I also turn to it for phone patch sessions – in other words, to connect to landlines and mobile phones where the client wants to listen in to a voiceover session on an ordinary phone. If you dial into Audio TX from a mobile or ordinary landline, (not through an ISDN codec) it will automatically configure itself into the G.711 codec required to make the connection. If you want to dial out you’ll need to select this option when you add a new contact.

But what about if you need to dial into a conference call where you need to send some DTMF tones to get into the right ‘room’…  Audio TX doesn’t have this facility, but if you are on a Mac you might find it useful to know that you already have all the DTMF tones hidden away in a folder deep inside your system folder.

With your Mac routed to your Audio TX – just play the relevant DTMF tones (select the file and hit the space bar to play) and bingo  – the conference door will open. So how to find them…on my Mac they are located here:

HD/System/Library/Components/CoreAudio.component – RIGHT CLICK (CTL) THIS ONE and then select ‘Show Package Contents’: then it’s Contents/SharedSupport/SystemSounds/Telephony – I’ve made a copy of this telephony folder somewhere less deep to make things easier.


The list of DTMF tones on your Mac. Note # is labelled dtmf-pound.caf


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