The MICO Shield makes it easy for you to create an Arduino project that interfaces with a cell phone. The Arduino &cell phone interface unlock a whole new world of possibilities: projects where your Arduino can place phone and receive phone calls.
 
An example of aMICO project is where it receivesa phone call and presents the caller with a voice prompt: “press 1 for lights on”. MICO can then decode the caller’s button press and take action、 in this case turn an output on. Of course everything is customizable: MICO has a microSD card slot so you can store your own voice and all MICO libraries and sketches are open source、 free to download and hack.
 
MICO interfaces to a cell phone’s 3.5mm audio jack. MICO has no build-in cell module or antenna. Because of that、 MICO provide some key advantages:
    Universal:can work on ANY cell network over the world! GSM、 CDMA、 TDMA、 analog…
    Rich features:can utilize new features cell phones have. For example: on the iPhone、 MICO can say commands to SIRI such as “post to twitter: temperature is 70degrees”. (of course、 you could instead just use an old phonefor basic function)
    Simple:no need to learn complicated AT commands. Phone is controlled just with Answer/End Call Button and voice out of the microSD card.
    Perfect for quick/temporary projects:no need to buy GSM card just to run a quick demo project. Just plug in your own/friend’s phone. No need to tear it open to grab the card、 or hack its software.

Feature
    DTMF decoding IC
    DTMF encoding play back recorded tone off microSD
    Answer/End Call button (physical and Arduino controlled)
    Play out sound to phone and to a headset
    Works both newer AHJ (iPhone/Android) and older OMTP phone standards
    Incoming audio amplified and read in by Arduino
    Foot print of Arduino UNO and Leonardo