What can we do? Tools and Media Description

We need first to identify what is our raw material? What can we use? What is our channel ?
Formally: What is the communication channel, what is the capacity and bandwidth, and what are suitable codes to use?

Well, actual formulation of the problem has been studied a long time ago. From the early starts, there has been the Morse Code, Nyquist and his work in telegraph capacity, etc. But we can go even further in history: Take for example the English language, short words are more common to be used (or the other way around, they have been chosen to be shorter because they will be used more often); like I, am, is, are, us, we, cat, dog. And on the other hand there is: umbrella, discriminate, cognitive, ... (Mostly, I will dedicate another post just for this)

The first main formulation was, of course, by Shannon and Kolomogorov (late 1940's 50's, and 60's). And since then, tons of theoretical work, and heavy applications have been developed (e.g., digital phone lines, cell phones, data compression as in images: jpeg, gifs, ... movies: mpeg, ... archive formats: zip, arj, ... and well, computer networks in general).

So, let's take it simple.
If we stand in front of each other what might be our tools:
Then, it depends on what are the different actions I can make, and what are the corresponding responses. I can wave, close/open my eyes, yawn, stick my tongue out, stand on one leg, ... or any combinations of them.

If we are over the phone?
I can start with a hello, or hi, or just "is this Bob?", ...
And you can answer back with anything similar.

We can go like this for every possible situation.
The information we want to communicate has to be translated to some sort of code (something we agreed on: if I waved my hand then the meeting is canceled, if I yawn, then just delayed, ...)

The important question is how much information I can send you with these naive ways?
How to measure/evaluate this: The way to measure it is to take the whole number of possible signals I can do. If it covers the different choices I want to send you then, we are done. For example, I can do 10 different things over the phone (as we mentioned before), and I want to tell you what hour of day we will be meeting (from 9am to 5pm). Then it is enough. We can keep the extra choice to say: "No way I am going out, got lots of home work to do, or my dad won't give me the car".

Formally: You would take the log (base 2) to find the number of bits you can use. And do the same with your original information. (or base 10 and it will be digits, ...)


Believe it or not, you will find we can say a lot without anyone noticing.
And of course this is our goal, otherwise why not say it loud and clear: "I will lower the bid on the contract by 100,000". You need to cough twice, sneeze once, and close the phone call exactly after 15 minutes in order to tell me it is a 100,000 not 90,000 and not 110,000.