ASK (Amplitude Shift Key).
ASK stands for Audio shift keying, it consists of two tones one for mark and the other for space. Is that what you have or is it AM, Amplitude modulation?
Given that either way it could be Manchester encoded.
Is this code asynchronous serial? Or is it synchronous?
You need to know these things before you can begin to figure out how to decode it.
Also what are you looking for and what do you want to do when you find it?