Yate as a PBX
From Yate Documentation
Yate can be used as a PBX. Depending on the functionality you want you can use a combination of Yate modules and external scripts.
Because putting it all together can be a hassle and can take quite a lot of time, Null Team launched FreeSentral, a full IP PBX based on Yate that is easy to set up and use.
By default Yate's PBX functionality is disabled because it reduces the number of calls Yate can handle for other types of setups. That is because in order to offer PBX features Yate needs a lot more control over the call leg than it's usually needed for other types of setups. This allows us to have control over the telephony channel when needed without creating a performance issue.