Enter the device address, press the simplex symbol in the center, and you have the switch settings for that device.Works for all Simplex brand fire alarm devices.Converts any address from 1 to 250.Much better than using those binary converters.Doesn39;t crash reads switches in the correct order, has a picture of the switches to help you get them correct.If you are a fire alarm installer or tech working with Simplex fire alarm systems, this is simply a MUST HAVE appIf you have problems, let me know.I have designed and used this on android v2.2 on an Elocity tablet screen size of 400X800If you would like changes, let me know.I can customize it for you