I have thought that it was possible, and i only need a range of at most 25-50 meters since it is only a link i want within a room within a mostly unobstructed line of site (although I still dont want IR). So because Im transmitting data, that means that I cant just plop radio transmitters and recievers alone the line? darn. So if I have it right, I have to encode it into a signal that can be transmitted via radio, then the signal is going to be detected by another reciever, then decoded, then it reaches the recipient calculator. then that calculator has to send data through the same jack back into the circuit, encoded, transmitted, recived, decoded, and it goes back to my calculator to be interpreted by my program to output a text message or just simply show that the other person has moved their character. I also think that it is going to have to have its own power supply for simplicity's sake (and also the fact that i am not authorized to open my calculator ) and its going to have to be at a set frequency and stregth to prevent being nabbed by the FCC. I also have to create a program that uses Ti-basic to actually communicate between the calculators. Also it needs to be removable for basic practicality's sake.
This is going to be tough.