At this point, it is worth thinking about the two fundamental views of communication, the transmission and the ritual view, and consider how ideas of the sign play out in each.
The transmission view, which was about the functional exchange of information from sender to receiver across space, can utilize signs as a vessel for the exchange of such information. The panoply of signs that surround us are all signifiers, and thus can be seen to at least be attempting to communicate or convey information.
In a ritual view of communication, which is about the idea of culture being developed over time, ideas are seen to be circulating a culture, and again through the use of signs to facilitate the exchange of meaning. What a sign ‘means’ is often determined and refined by culture, even for indexical signs. What meanings are dominant, what symbols correlate to what ideas, is constructed by culture. Again, think of the word ‘cool’ as an example of this in action.
This brings us to the concept of codes. In all the communication you have participated and been exposed to, we have had to ‘read’ and deconstruct the signs presented in context. We all bring to bear on the act of meaning-making our understanding of that context, and prior experiences with those signs to help make sense of the message being transmitted. To continue the example of this Instant Kiwi lottery advertisement, we read that ad referring back to our own personal experiences of exam situations, as well as other media texts that have presented similiar or parallel narratives.
Signs are not presented in isolation, one at a time. We can try and isolate them to study them, but we cannot fully make sense of them without taking into account the context. Signs, how they operate and how they relate signifier to signified, take place within systems that we call codes.
Take this New Zealand PSA commercial as an example, and think about the codes — the prior texts and experiences and meanings — you as the reader need to bring to bear to understand the message it intends to convey.