SIP REFER - Call Transfer
The IMG 2020 supports the SIP Refer method of transferring calls. This method utilizes the Refer-To Header field to pass contact information such as URI INFO provided in the request. The IMG 2020 has the ability to act as either a Transferee or a Transfer Target when used as part of the SIP Call Transfer functionality between three SIP User Agents. The IMG 2020 cannot become a Transferor. This will be left to an application written on a different server. Below is a short description of the three functions.
...
Basic Transfer (Unattended)
A) A connection between Transferor and Transferee is established through dialog.
...
Call has successfully been transferred to PSTN using SIP Refer
Transfer (Attended)
A) A connection between Transferor and Transferee is established through dialog.
...