As a picture is worth a thousand words.
Here is a list of my codec configuration for my Asterisk switchboard, with FreePBX.
Since in my case on many occasions the switchboard will be used from smartphones, to carry out this prioritization a sample has been made with several codecs and bandwidth, always 3G, to establish its order.
That is, with this configuration, we obtain an acceptable quality, even with the minimum of bandwidth.
