Blind / Attended Transfer via dss key

[Yealink Support]

Please change your common.cfg file to y000000000004.cfg, then fill it with below syntax and auto provisioning again.

-------------------------------------------------------------------------------
#!version:1.0.0.1
##It configures the DSS key behavior during an active call when user presses the DSS
##key and the DSS key is configured as a speed dial, transfer or BLF/BLF list key.
##0-New Call,1-Attended Transfer,2-Blind Transfer.
##The default value is 2.
transfer.dsskey_deal_type = 1
-------------------------------------------------------------------------------