Using a female 2.5 mm stereo inline jack [octanechicken ... a shameless link to a previous featured article moving the headphone jack on a new Yamaha DGX-630 keyboard.

While 2.5mm was the original standard for phone headsets, the slightly larger 3.5mm size is standard for music headphones and is now the more common size on phones. See: Headphone Jack (3.5mm ...

Some phones offer only a 2.5 mm jack, which is a smaller variety of the same principle. Headphones supplied with mobile phones usually have a mic somewhere along the cable and a remote button that ...