eak a different 'language' from network design engineers who speak a different 'language' from IT engineers. Engineers speak a different 'language' from product marketing and sales who speak a different 'language' from business modelling specialists who speak a different 'language' from lawyers and accountants who make the world go round. This is frustrating as, in reality; all these 'communities of interest and specialist expertise' have more in com- mon than seems initially apparent. 'Descriptive domains' provide a route to resolving these interdisciplinary communication issues. 21.12 A Definition of Descriptive Domains A descriptive domain is simply a mechanism for describing form and function The 'analogue domain' and the 'digital domain' provide two examples. The analogue domain can be widely understood in a modern context as a set of continuously variable values. In a linear system, the output should be directly proportional to the input. 1 http://www.mipi.org/. Making Telecoms Work This is the 'form' of the domain; its defining characteristic. The 'function' of the domain is to provide a generic method for describing the physical world around us. Light, sound and gravity and of course radio waves are all in the analogue domain. The 'form' of the digital domain is defined as the process of describing data sets as a series of distinct and discrete values. The 'function' of the digital domain is to provide a generic method for describing analogue signals as discrete and distinct values. Most people are comfortable with these descriptions but do not necessarily understand some of the practical implications of working in either domain. For example, an engineer might need to describe the fiscal merits of digital processing in terms that are accessible to an accounting discipline. This suggests the need to add in 'cost' and 'value' to the descriptive domain. Let's test the validity of this on some practical examples 21.12.1 Cost, Value and Descriptive Domains - A Description of Silicon Value As with many technolo