Does the 3.5mm Headphone Plug accept input as well as output?

My Computer is:

MacBook Pro (Retina, 15-inch, Mid 2014)

10.10.2 (14C109)

2.8 GHz Intel Core i7

16 GB 1600 MHz DDR3

500 GB SSD

NVIDIA GeForce GT 750M 2048 MB

Model Name: MacBook Pro

Model Identifier: MacBookPro11,3

Processor Name: Intel Core i7

Processor Speed: 2.8 GHz

Number of Processors: 1

Total Number of Cores: 4

L2 Cache (per Core): 256 KB

L3 Cache: 6 MB

Memory: 16 GB

Boot ROM Version: MBP112.0138.B14

SMC Version (system): 2.19f12

OSX: 10.10.2 (14C109)

I've got mixed answers from Apple Support and their engineers. The engineers might not understand the question, but it is simple.

Again, Apple only provides the most minimum of details possible, so there are no technical specs to fall back on.

By referring to it as a Headphone jack we can infer you can plug in a headset and listen to iTunes. Researching further I find you can plug in a 3.5 mm Headphone, provided you get a connection that follows the four connector Apple standard.

Since a headphone has a microphone I would assume that means the headphone jack can support input. For example, spoken words. Will the headphone jack support a 3.5 mm Apple specific wire connected to the MacBook and the other end to another device like an MP3 player, but using the proper four wire configuration for the MP3 Player?

If so, what application is available on the MacBook Pro to get the analog data and then manipulate it into something digital?