On the left, the Canon RS-80N3

In the center, a 3.5mm stereo plug and 3.5mm stereo jack. These are available on line at any electronics parts supplier for around $.50 US each.

On the right, a 25 foot stereo cable with a 3.5 mm stereo plug on one end and a 3.5 mm stereo jack on the other end. (I chose a 25 foot cable at a cost of $3.50 but they come in about any length you might think you need.

The stereo plug, jack and cable are also available at places like Radio Shack but the price will likely be a little higher.