AcquireSourceName example for Delphi
procedure TForm1.Button1Click(Sender: TObject);
var
nRet: Integer;
begin
LEADTwain1.AcquireSourceName:= 'TWAIN Source Name';
nRet:= LEADTwain1.Acquire (LTWAIN_SHOW_USER_INTERFACE);
if(nRet <> SUCCESS)then
ShowMessage('Error acquiring from source');
end;