if you have money, just buy one (no need for it to be the official thing. any 2.5mm male to 2.5mm male cable will do). if you don't, you're a bit out of luck, unless you are incredibly dexterous or have plastic moulding equipment

I have absolutely no money. I heard that you can just file down the plugs on a pair of headphones and splice 2 of them together.

Dangit, I only have 3.5 mm

You probably don't even need to file it down. I can use the 2.5mm headphones just fine to listen to music on the calc. I should look into a better method for making a cable, though. I have a 3.5mm to 3.5mm cable with two adapters for 2.5mm→3.5mm, but the connection gets kind of iffy and it needs to be just right for both lines to connect.

I'll try to file down my 3.5 mm headphones.

That is not going to work. I've soldered quite a few headphone plugs and I can tell you that you are dealing with a sandwich there. In order of getting smaller, you have: metal jacket, plastic jacket, metal jacket, plastic jacket, metal rod. The the trouble here is that I wouldn't doubt that the 2nd metal jacket is around 2.5 mm. This means that you're going to have to completely file off the outer jacket, at which point you no longer have a plug.


So, I recommend you try to find 2.5 mm plugs. The most common place these show up is in xbox-live headsets. So ask your friends at school if they have any broken headsets you could have. Chances are if you ask enough people, eventually you'll have 2 because these things tend to break often. (Turtle beaches also come with the correct 2.5mm to 2.5mm cable, but I doubt people will give you that cord) Then just cut the two wires, strip them (remove plastic covering from copper), and match the 3 wires inside.

If you're not sure which wire is which, you can use a battery and a christmas light to determine what wire goes where.

I usually look for weird cables in the local thriftshops I buy cables I like such as 2,5mm jack, 5pin din, 8pin din. The stuff you cannot get easily in stores anymore. I got some 2,5mm cables that actually fit the calc.