====== DTMF ======
Referencias:
  * [[http://www.genave.com/dtmf.htm|DTMF Explicado]]
  * [[http://www.electronic-circuits-diagrams.com/remotecontrolsimages/remotecontrolsckt5.shtml|Radio Control usando DTMF]]
  * [[http://en.wikipedia.org/wiki/DTMF|DTMF en la Wikipedia]]
  * [[http://manpages.ubuntu.com/manpages/gutsy/man1/multimon.1.html|Multimon software - Program to decode radio trasmissions]]