res were introduced, to allow speech circuits to flow around; hence the use of the term 'loop'. Copper is suitable for low transmission rates, such as voice or data using modems. However, for the broadband applications which are increasingly being used in businesses and homes, it is too slow. Multimedia Optical fibre is competing with traditional copper lines in the local loop (Fibre In The Loop, or FITL), although the cost of replacing copper to all homes is high. Many techniques are used, such as Fibre To The Home (FTTH) and Fibre To The Curb (FTTC), which use Microelectronics Software star, bus or rings with passive optical waveguide couplers and converters per group of subscribers. Radio In The Loop (RITL) is also being used for ease and quick- ness of implementation. Wireless Optical 11.5.2.2 Intelligent networks Intelligent Networks (IN) are based on processing within the public network architecture. They enable PTTs and other service providers to give a service to their customers which would be difficult to provide on a private network. The key advantages of intelligent networks, in service provision, are: Figure 11.9 Core technologies and application technologies 1. The ability to offer new and advanced facilities. 2. All staff within an organisation can have access to equal ser- 1. Microelectronics, where the implementation of increasing vices, irrespective of the branch in which they are located. functions on a silicon chip, having submicron channel struc- It enables operational services to be more easily sub-con- tures, high speeds and low power consumption, has resulted in tracted. enhanced performance, reduced costs and smaller equipment It provides flexibility of services, and the ability to change sizes. quickly between the various services being subscribed to. 2. Software, where advances in technology and development standards have resulted in enhanced reliability and perfor- mance. 11.5.2.3 3. Optical, which includes optical fibres, with increasing capa- cities and the ability to transmit over lo