Support for First-Party Call-Control Operations
Beginning with the Siemens OpenScape Voice switch release V5, SIP Server provides support for first-party call-control (1pcc) operations, including a transfer that uses the REFER method when it is integrated with the OpenScape Voice softswitch.
To support 1pcc operations, you must configure a DN of type Voice over IP Service DN and Extension DNs. See Configuring DN Objects for details.
To enable a blind transfer, set the blind-transfer-enabled configuration option to true, at the SIP Server Application level, or at the Voice over IP Service DN level.
There are several known limitations that result from the Siemens OpenScape Voice release V5 integration:
- Mix of 1pcc and 3 pcc with a call is not supported.
- For 3 pcc calls, the re-INVITE--based call control method is used.