Byte -> Bin

function ByteToBinStr(a_bByte: byte): string;
var
 i: integer;
begin
 SetLength(Result, 8);
 for i := 8 downto 1 do
 begin
   Result[i] := chr($30 + (a_bByte and 1));
   a_bByte := a_bByte shr 1;
 end;
end;