Voice Portal feature by protocol compatibility chart

Feature
H.323
H.323 with SA8874
SIP

Outbound calling using the Application Interface web service
Partially supported
No call progress information is available, so an application may start before a call is answered
Supported
Supported

Blind transfer
Supported
Supported
Supported

Supervised transfer (also called consultative transfer)
Operates like a blind transfer
Note: The only supported VoiceXML event for this transfer is error.connection.noroute.
Supported
Supported

Bridge transfer [...]