Wired Headsets: A Tutorial on Connectors, Cables & Pinouts
Prior to smart phones life was much simpler…at least with respect to the wiring for headsets used with portable music players vs cell phones. A recent project has me dealing with some wired headsets. I thought it worth sharing some of the things that I’ve noted along the way, along with just a bit of the history.
What I’m describing relates to the various ways in which the common headset connector has been used over time and across a number of application contexts, including:
- Music players
- Desk phones
- Smart phones
- Computers
In the beginning there was the pocket transistor radio. When Sony got around to it some transistor radios featured a 3.5mm (1/8”) 2-conductor jack. This was intended to receive an earphone for private listening. It was also called a “mini-jack” since stereo headphones for listening to music used the full-sized, 1/4” phone plug.
It’s unclear if the creation of the earphone feature was motivated by the desire to listen to the radio after bedtime, or avoid aggravating the Mrs with the play-by-play of the baseball game.
…time passes, until…
Plantronics has recently opened 
is the way it knows when you’re wearing it. If the headset is paired to my cell phone and I’m wearing the headset it will answer an incoming call.