I think it's possible to write a program in Asm or C that could communicate with all CASIO-calculators. The CASIO have a link-port with serial communication using fixed lines for send and receive, but TI is more flexible and can use both lines for sending and receiving. Thus, the TI-calculator should be able to emulate serial communication. Since both TI and CASIO calculators use 4.5 V they probably have the same voltage levels on the link ports. There are open source programs for Linux to communicate with the CASIO calculators using an official CASIO-link (which is just a voltage converter since the standard serial protocol is used). If one could modify such a program to use the $4-link or the black link (TI-Graph Link) one would be closer to making a program for the TI-calculator. Does anyone think this would be impossible or very difficult?
I have some CASIO-calculators but no CASIO-link. I do have some CASIO-calculators that can exchange programs via the link ports.
Here are some links to programs that can be used to figure out the CASIO link protocol:http://xizard.free.fr/logiciels/XI_interface/XI_interface.htmlhttp://sourceforge.net/projects/cafix/files/http://tuxmobil.org/calculators_unix.html
I think this TI-program would be useful for teachers in classes were students have mixed TI and CASIO calculators and that one could transfer programs and data between the students and the teacher. If a teacher wants to transfer a CASIO program from a TI-calculator the program would be stored in the TI-calculator as e.g. an encoded list and then transferred using the program.