ShadyModemInABox is a simple implementation of @davidmc's design for ShadySoftModem and YATE in a single Ubuntu container, using tini as the init, which can be configured to accept SIP or link via SIP/IAX2 and provide simple modem services to a VoIP network.
Most commonly used for PPP.
Configure YATE as appropriate from the yate.conf.d directory, or optionally attach it as a volume for dynamic configuration and run the container.
Running ./build.sh will build an image tagged with alexhorner/shadymodeminabox:latest which you can then run to test with a simple docker run --rm -it alexhorner/shadymodeminabox.