var
CardInformation : WideString;
pCardInformation : pWideChar;
...
GetMem(pCardInformation, 255 * 2);
try
ReadCardResult:= MyCompActX.ReadInformation(pCardInformation, 20, 20, 1, 'INGRESE NUM...');
CardInformation := pWideChar(pCardInformation);
finally
FreeMem(pCardInformation);
end;
...