How to Link the TI-84 Plus to Other Calculators
You can transfer data lists, programs, matrices, and other such files from one calculator to another if you link the calculators with the unit-to-unit link cable that came with your TI-84 Plus calculator.
Calculators are linked using the unit-to-unit link cable that came with the calculator. If you’re no longer in possession of the cable, you can purchase one at the Texas Instruments online store.
The unit-to-unit link cable for the TI-83 can be used to link a TI-83 to a TI-84. It can also be used to link two TI-84s.
The unit-to-unit link cable connects to the TI-84 calculator at the port at the top of the calculator. On the TI-83, it connects to the port at the bottom of the calculator. If you want your TI-84 to link with a TI-83, you need an I/O-to-I/O cable — that’s the cable having a plug on both ends.
If you get an error message when transferring files from one calculator to another, the most likely cause is that the unit-to-unit link cable isn’t fully inserted into the port of one calculator.