Audio Serial Out is a free utility app developed by spiritplumber for Android devices. With this app, you can output serial commands from the audio port of your phone and control any serial device such as Arduino, BASIC Stamp, etc. without rooting or using Bluetooth. You can also call this app as an intent or integrate it with other apps. The app offers the option to order a cable for only $15 or build your cable by emailing for source code and schematics.

The app is user-friendly and easy to navigate. Audio Serial Out is a great tool for those who want to control their serial devices from their Android phone. The app is compatible with most Android devices and can be downloaded for free from the Google Play Store.