Origin
Origin is a general description of where the session started, such as whether it is external or internal to a corporate network. See LINECALLORIGIN_ Constants for a listing of origins that TAPI supports.
Not all service providers support use of this information.
TAPI 2.x: See lineGetCallInfo (dwOrigin member of lpCallInfo).
TAPI 3.x: See ITCallInfo::get_CallInfoLong (CIL_ORIGIN member of CALLINFO_LONG).