Comment
An application can set a comment during the initiation of a session. Comments are often used for logging purposes.
Not all service providers support use of this information.
TAPI 2.x: See lineGetCallInfo (dwCommentSize and dwCommentOffset members of lpCallInfo).
TAPI 3.x: See ITCallInfo::get_CallInfoString (CIL_COMMENT member of CALLINFO_STRING).