State of knowledge

March 2021


In the constellation 3CX PBXYealink end devices (model-independent) and the uaCSTA it happens that

  • Incoming and outgoing calls are not always signaled.
  • Status information is displayed incorrectly or not at all in the ProCall Client  .
  • The uaCSTA shows no connection to the end devices or can only be connected sporadically. 


Yealink end devices can only process CSTA via one identity. Like the uaCSTA, the 3CX telephone system also uses the CSTA protocol. If CSTA is activated on the 3CX, there will be problems processing information on the Yealink end device. The different error patterns described above may occur.


Disable CSTA on the 3CX telephone system.
Please refer to the documentation for the 3CX telephone system for information on how to make these changes.

estos guidelines for the support of third-party products – interoperability information apply.