This serial modem brought to you by Switch Science allows you to interface an Arduino board with your iPhone or Android smartphone through the audio jack. Now you can integrate your smartphone into your next embedded project. Some software is required on the phone side, and of course there is an Arduino library.
Because the modem and supporting software exploits a connection originally intended for audio, some corruption of the serial data is to be expected from time to time. It's recommended that you keep this in mind when writing your code. See the links below for more information on the board, the Arduino library, and how to implement it.
Note: A standard 3.5mm stereo headphone cable will not work correctly with this board. You must use the special 4-pole cable such as you would find on a wired headset. The audio jack shown does come with the board, but is not soldered to the board.