To get programs on your calculator, you don't really have to use the software or the cable. However, to get programs to your calculator easily, I recommend that you get both. You actually need the TI-Graph Link sofware more than you need the TI-Graph Link Cable. You can live without the cable, but you'll just have to input the code for the program by hand into your calculator. There is a pretty big chance for making an error doing it this way. The reason you really need the software is because most archives do not offer text-based versions of their programs. All the offer are the calculator files. If you do not have the software, there is no way for you to view the code that the calculator file contains. This is quite obvious, but I think it needs to be said. If you have the TI-Graph Link Cable, you definitely need the software. There's no way the cable can work without the sofware. Plain and simple: the software can work without the cable, while the cable cannot work without the software.