Can an iPhone 4S take microphone through audio jack? I can play audio of an iPhone 4S through the 3.5mm audio jack to headphones. I would like to use it with a headset that includes a microphone for making phone calls or recording audio. I'm not sure if it's compatible and have not found details from the technical specifications.

Can I speak and hear a phone call on an iPhone 4S with a headset that includes a microphone through the jack 3.5mm line?
It does work for the standard earphones which are included when you bought an iPhone 4S so it's safe to assume that it works for other headsets as well, at least if their use of the audio jack is the same (which it should be, actually).

PS: See this product listing on apple.com for an example.