Signalling

The Art of Communication
http://www.shurdington.org/Downloads/The%20ART%20of%20COMMUNICATION.pdf 
   
The Morse Code
http://en.wikipedia.org/wiki/Morse_code 
  
Chart of Alphabets and Numbers in Morse Code
http://upload.wikimedia.org/wikipedia/commons/b/b5/International_Morse_Code.svg 
   
Signalling with Flags
http://www.anbg.gov.au/flags/semaphore.html 
  
International Maritime Signal Flags
http://en.wikipedia.org/wiki/International_maritime_signal_flags 
   
International Code of Signals
http://en.wikipedia.org/wiki/International_Code_of_Signals