I'm building an electronic musical instrument which I would like it to have a 3.5mm audio output socket, so it would work with any "regular" headphones, like a cellphone does.
For a long time, I've tried to googling the electrical standard for such a socket (having TRRS + CTIA connection) and couldn't find one.
- How should I design my signals for the connection?
- What are the voltage ranges?
- What is the output impedance my circuit should show?
- Is the analog signal being the signal being played? or the socket output signal contains some sort of modulation?
If you could please clarify how should I accessing the socket subject,