I'm trying to communicate with an android phone using the mic pin on the audio connector. I have a range of voltages that I want to send across the audio connector and read them using AudioRecord. I think the audio jack interface is used for analog audio signals which uses varying voltages as a sin wave, but is it possible to just send some current with a voltage that varies but is not continuous? For example, send, at first, a current with .1v then later send a current with .12 volts? I would have some external device send a current to the mic pin. If I connect a .1 volt current to one side of the mic pin, and plug the other into my phone, can I record a value that correlates to the .1 volt? If not, how can this be achieved? Must I use an alternating current? And what range of voltages can you feed into the mic pin?

Also, if anyone has some good links regarding how everything about the audio connector works, I'd appreciate the references.