An attended transfer is one where a user A recieves an external call, he wishes to transfer to user B, user A calls user B and confirms they are willing to take the call then if they confirm they transfer to user B if not they hang up.
An unattended (blind) transfer is one where user A recieves an external call, he wishes to transfer to user B, user A transfers to user B and hangs up. If user B is busy or doesnt answer the call goes to voicemail.
On Asterisk there is talk of using the features.conf file to specify a short code (e.g. *2) to perform a transfer, ive tested this and never been able to make it work, however I have managed to find a way it can be done by using the manual!
To perform an attended transfer:
1. Answer call.
2. Press the “FLASH” button, you will then hear a dial tone.
3. Dial the third party’s (phone you want to transfer to) number and press “SEND”
4. If the call is answered and the user wants the call press “TRANSFER” to complete the transfer.
4a. If the call is not answered pressing the “FLASH” button to resume the call.
To perform an unattended blind transfer.
1. Answer call.
2. Press the “TRANSFER” button, you will then hear a dial tone.
3. Dial the third party’s (phone you want to transfer to) number and press “SEND”
4. Hang up your phone.