Hi there, I can find a few threads about CTI but they are locked. I have 3CX Phone System v12.0.33517.465 and the Yealink T20P handsets. I can use 3CX Phone for windows in 3CX phone mode, but not in CTI mode. I have updated the firmware to V70-IUK 22.214.171.124 as recommended in earlier posts. When dialling from the physical phone, 3CX for windows displays the number and status. When dialling from Windows, I can type in the number but when I press Call, nothing happens. With Avaya, I remember we needed the TAPI driver for AVAYA installed. Is this the issue here and where can I get the driver from? Thanks.