TRRS Phono Plug
This audio jack is similar to the TRS Phono Plug, with the exception that there is an additional ring, resulting in a Tip + Ring + Ring + Sleeve configuration. The TRRS phono plug facilitates the addition of another connection since there are 4 contact places on the jack separated by three insulation layers. The two most common applications today for the TRRS phono plug in Mini Phono is for video camera recorders and mobile audio devices including the iPod, iPhone, and Android phones.
Polarity
Audio Devices
The most common audio device application for the TRRS connector is the microphone + headphone headset. The stereo headphones include a microphone for use with modern mobile phones, such as the Motorola Droid. These hands free headsets utilize the additional contact on the jack for the microphone, and share a common ground.
Unfortunately, there are competing conventions for the contact assignment of these TRRS phono plugs. The original convention has been established for decades and was adopted by Nokia for their mobile phones for hands free headsets. For the purposes of identification it will be referred to as the Nokia convention.
| Tip | Left Audio |
| Ring | Right Audio |
| Ring | Microphone |
| Sleeve | Ground |
Then along came Apple with their iPod and iPhone audio devices. Rather than accepting an existing convention, Apple created chaos for device manufacturers by swapping the microphone and ground connections.
| Tip | Left Audio |
| Ring | Right Audio |
| Ring | Ground |
| Sleeve | Microphone |
By preserving the left and right audio convention it allows the use of standard TRS headphones on apple devices. Although connecting TRS headphones does short the ground and microphone connection, it reportedly does no harm and full stereo audio is available in the headphones.
