It is fairly simple to use once you know how to use it. However, the tricky thing is that by default it doesn't seem to be active or listen on any interface on manually specified.
How To Install ifplugd
First we install ifplugd
sudo apt install ifplugd
Let's enable it on our desired device(s)
vi /etc/default/ifplugd
set this line as so:........
NOTICE[11389]: rtp.c:1808 ast_rtp_read: Unknown RTP codec 100 received from
I've found that trying several times may work, but I also read changing your Sipura VOIP adapter settings as follows helps (but it still fails for me sometimes):
In adapter change the following under SIP/Advanced
Codec to G711a from G711u
Passthru Method from: NSE to ReINVITE
FAX CED Detect Enable: Yes
FAX CNG Detect........