TI-85 Headphone connection

Boris Lutz

Material Needed:

• All you need is a 2.5mm (plug) to 3.5mm (plug) stereo adapter from Radio Shack
• If you can't get one you might try to build one on your own by buying a 2.5mm stereo plug, a 3.5mm stereo plug and connecting them with a three conductor wire. To do this you will also need a continuity tester.

Introduction:

With this cable you can connect a headphone to your TI-85, but it will slow down the calculator if you are not in ZShell.

Schematics:

                                 ADAPTER        
            _______________                    _______________
           | 3.5mm phone   |                  | 2.5mm phone   |
           |    plug       |========//========|    plug       |  
           |_______________|                  |_______________|
 

Building the adapter:

1. Strip both ends of the three conductor wire so that about 1/4" of bare wire shows.
   
2. Solder one wire to the largest terminal of the 3.5mm plug and the other end to the largest terminal of the 2.5mm plug.
   
3. With the continuity tester, determine which terminal is connected to the tip of the 3.5mm plug. Solder the second wire to this terminal. Solder the other end of this wire to the terminal of the 2.5mm plug which is connected to it's tip (use the continuity tester again)
   
4. Solder the last wire to the last terminal of each plug.
   
5. Be sure to cut off any excess bare wire that may be able to touch any of the other terminals.
   
6. Slide the cover onto the other end of wire and screw it on.

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