State of knowledgeMarch 2023

estos ECSTA for SIP Phones 6.x

estos ProCall Enterprise 8.x/7.x


If a call forwarding is sent via ProCall Enterprise and ECSTA for SIP phones to a Yealink end device connected to estos uaCSTA, the call forwarding status is displayed as expected in the ProCall Enterprise client and on the Yealink end device.

If call forwarding is set directly on the end device, the call forwarding activated there is not displayed in ProCall Enterprise client. In ProCall Enterprise client, it looks as if no call forwarding is set at the end device.

A cross-check independent of estos ProCall Enterprise using the test tool EPhoneX64.exe/EPhone.exe also shows this misbehavior. If a call detour is sent to a Yealink device via EPhone.exe using ECSTA for SIP Phones, the TAPI Test Tool itself does not display the set call detour as expected.


Call forwarding activated on the Yealink end device is transmitted via forwarding request to the PBX account, but not to the additional end device account for the uaCSTA connection.
uaCSTA therefore does not receive any information about the call detour set directly on the terminal device and cannot forward them to the ProCall Enterprise server via the TAPI interface.


This problem has been analyzed repeatedly by estos. Regarding a solution, it is suggested to contact the support instance responsible for Yealink end devices.