Tip-Ring-Ring-Sleeve style audio cables are often used for situations where you want stereo audio and then an extra contact for a microphone input. . Also called TRRS jacks for short, they're also handy if you happen to want to use common audio cables for low-speed data transmission with power, ground and two data lines.

This breakout board is simple but has everything you need to interface with TRRS cables: not only do you get the four contacts but also two switched outputs:

• When the jack is not inserted, the left switch is connected to the left contact and the right switch to the right contact.
• When the jack is inserted, the left and right switch pins 'float'. You can use these switches to auto-switch from a built in speaker to headphone when plugged in, or .

We like this jack in particular because it has two through-hole contacts near the opening for a good mechanical connection. Comes fully assembled on a breakout board with mounting holes and lil bit of header in case you want to use it with a breadboard.