Hi Ahsan, This feature should be supported by the phone not the PBX. Normally, most of hardware phone already build-in transfer key. If you are using ATA adapter, most of them are already predefined transfer feature as well. Please let us know which hard phone in-use. For Grandstream HT488: Blind Transfer This function is applicable on FXS port for VoIP calls only. Assume that call party A and B are in conversation. A wants to Blind Transfer B to C: 1. A press FLASH on the analog phone to hear the dial tone. 2. Then A dials *87 then dials C’s number, and then # 3. A can hang up.