Reason
The possible reasons for an incoming session, such as that it was transferred, are listed in the LINECALLREASON_ Constants.
Not all service providers support use of this information.
**TAPI 2.x: **lineGetCallInfo (dwReason member of lpCallInfo)
**TAPI 3.x: **ITCallInfo::get_CallInfoLong (CIL_REASON member of CALLINFO_LONG)