This 2.5mm TRS miniature connector is commonly used on cell phones and small electronic devices. 2.5mm connectors are slightly smaller than 3.5mm head phone connectors, but look identical.
This is a TS or mono plug (note the single stripe on the connector) This provides single channel analog audio.
TRS (Stereo) Plug (Male)
This is a TRS or stereo plug (note the two stripes on the connector) This provides a stereo or 2 channel analog audio. Commonly found on headphones
TRRS Plug (Male) 4 Conductor
This is a TRRS 4 conductor plug (note the 3 stripes on the connector) This can provide 2 channel audio plus a microhone. Also capable of 2 channel audio and a video feed. This is commonly found on iPhone headsets and portable DVD players.
