It is a renowned phenomenon that a sign or a signal is a representation of information. Moreover Drestke claims that a sign or signal can carry only one piece of information in ‘digital form’ and any other in ‘analogue form’ in that the latter is nested in the former. After having checked in literature, a problem is dawn to us, namely no one seems to have explained how such pieces of information may be identified. We believe that it is desirable to address this problem at least as far as information systems are concerned. This is because, once identified, only such information needs to be represented explicitly and all others would be automatically represented as a result. This may applicable to database design, knowledge discovery and semantic level interoperability in the IT field, and also other fields, such as production, manufacturing and quality control where the Pareto principle could be applied. Our approach is based upon a mathematical theory of information flow, namely Barwise and Seligman’s information channel theory through a case study on commonly seen traffic light. A channel is formed and the question in problem is addressed by defining the notions of classification, infomorphism, state spaces, core of the channel, constraints and serial composition of the channel.