anchor.diff:  			<<SSN:8, Remain/binary>> = BinSSN;
   		_ ->
   			Remain = BinSSN,
  -			SSN = undef
  +			SSN = undefined
   	end,
   	{Remain, SSN}.
   
  
positive.code: 
  encode_pc(PointCode) when is_integer(PointCode) ->
  	case PointCode of
  		undef ->
  			{0, <<>>};
  		_ ->
  			{1, <<PointCode:16/little>>}
  
negative.code: 
  encode_ssn(SSN) ->
  	case SSN of
  		undefined ->
  			{0, <<>>};
  		_ ->
  			{1, <<SSN:8>>}
  