Phones with 3.5 mm jack

Headphone output 3.5 mm (mini-Jack)

— determines if there is a mini-Jack 3.5 mm connector in a smartphone.

This jack is often referred to as a "headphone output", which corresponds to its main purpose: most often, the mini-jack jack is used for wired headphones, headsets and other audio equipment with suitable plugs (for example, portable speakers). However, other, more specific applications are also possible — for example, working with a card reader or exchanging data with a wearable fitness sensor.

Anyway, the mini-jack output provides the device with additional features. And its presence is specified due to the fact that relatively recently smartphones have appeared that are not equipped with a 3.5 mm output, and this design also has some advantages; see "without mini-Jack (3.5 mm)" for details.