uses 
  WinInet; 

const 
  MODEM = 1; 
  LAN = 2; 
  PROXY = 4; 
  BUSY = 8; 

function GetConnectionKind(var strKind: string): Boolean; 
var 
  flags: DWORD; 
begin 
  strKind := ''; 
  Result := InternetGetConnectedState(@flags, 0); 
  if Result then 
  begin 
    if (flags and MODEM) = MODEM then strKind := 'Modem'; 
    if (flags and LAN) = LAN then strKind := 'LAN'; 
    if (flags and PROXY) = PROXY then strKind := 'Proxy'; 
    if (flags and BUSY) = BUSY then strKind := 'Modem Busy'; 
  end; 
end; 

procedure TForm1.Button1Click(Sender: TObject); 
var 
  strKind: string; 
begin 
  if GetConnectionKind(strKind) then 
    ShowMessage(strKind); 
end;