Previously when [octanechicken] added a 2.5 mm female phone adapter at the end of the cable he did not connect the black wire to anything being it was the 2nd side of a push-pull speaker.

The former ended his with a 2.5mm female plug, the latter ended his with a 2.5mm male plug. You can choose the one (links below) that you prefer.

He added both a PSP headset style connector and a standard 2.5mm plug to a custom pigtail. Then he can use it with either a PSP headset remote or a modified USB PS/2 headset adapter. permalink ...

The trigger described in the tutorial should work with most digital cameras with a 2.5mm plug for remote triggering (including the popular Canon Rebel). From start to finish the project takes ...

The CTP-J-2504 family of SMT, 2.5 mm jacks have either three-position stereo or the choice of two styles for the four-position standard plugs. Made of Nylon 6T, these jacks have a melting point of ...