This function must be called immediately after lineInitializeEx to ensure that correct TAPI notifications are sent to your application. Call this function for every line that your application uses.

LONG
WINAPI
lineNegotiateAPIVersion(
HLINEAPP hLineApp, 
DWORD dwDeviceID, 
DWORD dwAPILowVersion, 
DWORD dwAPIHighVersion, 
LPDWORD lpdwAPIVersion, 
LPLINEEXTENSIONID lpExtensionID 
);