This is a temporary workaround for https://project.iopsys.eu/issues/4141, i.e. DTMF events
can not be detected and silent egress RTP payload for incoming calls.
The latest working version is SMARTHUB3-GFAST-IOPSYS-6.1.0ALPHA0-210112_0249. The problem
starts with SMARTHUB3-GFAST-IOPSYS-6.1.0ALPHA0-210113_0331. Note that this was just a test
result on one SmartHub3 device. It may vary on other devices.
Between these two nightly build versions, there were some dectmngr changes. Simply stopping
dectmngr process by "service dect stop" may cause the bug disappears. Copy dectmngr from the
second firmware to the first one, then the problem happens too.
So it seems that changes in dectmngr causes the FXS issues. Further investigation in dectmngr
will be undertaken.
