// Pleace notice, I called the Lan Adapters within a function Lana
// Outside a function I named them Adapter
FUNCTION GetMacAddress(AdapterID : Integer) : String;
TYPE
 TAdapterStatusA = record
   Adapt : TAdapterStatus;
   NameBuff : array[0..30] of TNameBuffer;
 end;
VAR
  NCB :TNCB; //Network Control Block
  ReturnCode :Char; //Retun Code
  AdapterStatus :TAdapterStatus;
BEGIN
 //Clear NCB Structure
 FillChar( NCB, SizeOf(NCB), 0 );

 //Programm NBC to fulfill a reset. It doublecheck if the Lana is present.
 //Can be removed, when used with GetAdapters.
 NCB.ncb_command := Char(NCBRESET);
 NCB.ncb_lana_num := Char(AdapterID);

 //Process NCB to NetBios
 ReturnCode := NetBios(@NCB);

 //Check if query was successfull, if returnCode = #0
 IF ReturnCode <> #0 THEN
 BEGIN
  // Return the negative returncode
  // Error check would be "if ReturnCode[0]='-' Then..."
  Result:=Char(Ord(ReturnCode)*-1);
  Exit;
 END;

 //Clear NCB Structure
 FillChar( NCB, SizeOf(NCB), 0 );

 //Programm NBC to ask for the MAC associated with the LanaID
 NCB.ncb_command := Char(NCBASTAT);
 NCB.ncb_lana_num := Char(AdapterID);
 NCB.ncb_buffer := @AdapterStatus;
 NCB.ncb_length := SizeOf(AdapterStatus);
 StrCopy(NCB.ncb_callname, '* ' );

 //Process NCB to NetBios
 ReturnCode := Netbios( @NCB );

 //Check if query was successfull, if returnCode = #0
 IF ReturnCode <> #0 THEN
 BEGIN
  // Return the negative returncode
  Result:=Char(Ord(ReturnCode)*-1);
  Exit;
 END;

 //Return formated MAC
 result:=Format('%2.2x-%2.2x-%2.2x-%2.2x-%2.2x-%2.2x',
                [ORD(AdapterStatus.Adapter_address[0]),
                 ORD(AdapterStatus.Adapter_address[1]),
                 ORD(AdapterStatus.Adapter_address[2]),
                 ORD(AdapterStatus.Adapter_address[3]),
                 ORD(AdapterStatus.Adapter_address[4]),
                 ORD(AdapterStatus.Adapter_address[5])])
end;

//Function GetAdapter
//=================
//
// This function will return the the total nummber of all lana's istalled
// and a unique the id of each lana.
// E.g. on a system containing lana's 0, 2 and 3, a structure with
// length =3, lana[0]=0, lana[1]=2 and lana[2]=3 will be returned.
FUNCTION GetAdapters: TLanaEnum;
VAR
  NCB :TNCB; //Network Control Block
  LanaEnum :TLanaEnum; //Enumeration of Lan Adapters
  ReturnCode :Char; //Retun Code
BEGIN
 //Clear NCB Structure
 FillChar(NCB, SizeOf(NCB), 0);
 //Clear LanaEnum Stucture
 FillChar(LanaEnum, SizeOf(TLanaEnum), 0);

 //Programm NBC to ask for the number of Lana's
 NCB.ncb_Command := CHAR(NCBENUM);
 NCB.ncb_buffer := @LanaEnum;
 NCB.ncb_length := Sizeof(LanaEnum);

 //Ask NetBios
 ReturnCode := NetBios(@NCB);

 //Check if query was successfull, if returnCode = #0
 IF ReturnCode <> #0 THEN
 BEGIN
  LanaEnum.Length := CHAR(0);
  LanaEnum.Lana[0] := ReturnCode;
 END;

 // Return valid LanaEnum Structure
 Result := LanaEnum;
END;


PROCEDURE TForm1.Button1Click(Sender: TObject);
VAR
 L_Enum :TLanaEnum;
 i :INTEGER;
BEGIN
 L_Enum := GetAdapters; { enumerate lanas for WIN NT }
 IF L_Enum.Length = '0' THEN
 BEGIN
  Exit;
 END;

 FOR i:= 0 TO (BYTE(L_Enum.Length) - 1) DO
 BEGIN
  ListBox1.Items.Add(getMACaddress(BYTE(L_Enum.Lana[i])));
 END;
END;