Asterisk-stable is a re-work over famous Digium's Asterisk.

We use it combined with our Smartswitch product on our customer's setups.
Our customers usually are telecom companies, for whom reliability and productivity are the main objectives.
Then, they need some bug fixes to operate with different equipment and vendors.
And finally, they need some more features which are absent in original Asterisk, but are really needed in telecom business.

From our side, we don't feel happy with standard Asterisk build system, so we have moved to CMake

Asterisk-stable is a vanilla Asterisk distribution that receives a set of patches which solve these needs.
When we decide to move to new Asterisk version, we take vanilla Asterisk from Digium and apply our patches (and while using it in production, we create new patches).

Some important patches we have:
  • implementation of T.38 support for H323 channel driver
  • implementation of "direct RTP" mode for H323 channel driver
  • support for binding to several networks for H323 channel driver
  • various bug fixes for H323 channel driver
  • CDR logging in telco mode
  • fixes for DTMF handling
  • codec2 support
  • AMR codec support
  • SILK codec support
  • MP3 format support
Asterisk-stable should be better used with other projects from our site for better performance and reliability, like:

So, if you need more stable Asterisk, which is built using CMake build system and has some features that are absent in standard Asterisk - it's the right place for you.