Sorry about that, I just signed up and wasn't aware of the rules! The reason for this project is I am currently working as an intern over the summer at a company in my area. They have a new electronic device that will be released at some time in the future and part of my intern project is simulating this device(and it's external programmer) through the use of two arduinos. The device will read a '0' for every 250us interval where a 400khz signal is present and a '1' when there is no 400khz signal. thanks for the help.