People have thought that we could send signals out into space and have communication back, but there is a problem.

How are we suppose to communicate if we don't know how their, the alien's, technology and language work for them?

if we don't know

 

      Non-verbal. Remember this one, http://en.wikipedia.org/wiki/File:Arecibo_message.svg. If they're stupid they may not understand.

how are they suppose to know what frequency we would be on and how what we would be trying to communicate to them

      1420.40575177 MHz The frequency of H2 ionization. 21-centimeter radiation was used first by the Aricebo attempt. Since that time they broadcast and listen to several million frequencies simultaneously. There is no way to know for sure but if anyone is there to receive the signal they have the same problem.