Communications basics.  Channel. Message. Environment. Interferences

As we have discussed interaction loop and its participants, now it is time to go back to basics — to communication fundamentals.

Communication is the conveying of any kind of information by any type of media between two or more participants. There can be a single direction communication (also known as simplex), when one participant is sender, and another is receiver. Of course, there are also bidirectional communication (duplex), when the sender is also the receiver and vice versa.

Let’s take a look at the process of communication from sender to receiver:

  1. The trigger of communication act is some purpose, intention or any other motivation of the sender.
  2. The sender prepares the message he wants to send to the receiver.
  3. Then he encodes the message to the format, that fits the medium/channel between sender and receiver — for instance, converts it into sound waveforms or writes the message with muscles of hand on the letter blank page.
  4. After it the encoded message is transmitted via the medium/channel to the receiver — by air for voice messages, by physical transportation of letter, by wires and so on.
  5. The receiver decodes and interprets the message (for instance, converts the waveform or symbols on the paper into meaningful words and phrases).

If the receiver wants to answer to the sender, he becomes the sender, and the steps are repeated in opposite direction.

At every step of communicative process the message can be distorted — during conversions, during transmission, even during preparation and interpretation of the message.

What is more important for HMI, is that there are multiple message encodings and decodings during single communication transmission. This also means, that every conversion changes the initial message, increasing the risk of unnecessary distortions.

Next: Subject domain