h as number of sockets and cost. The information can ever can. They also allow the user to view a number of options and be maintained with each symbol, or pointers associated with the all the relevant information at one time and on the same drawing. symbol will allow the user access to the relevant information in a Drawings from the architect can be merged electronically with the database. services layout or the space planning drawings. Modern computer Symbols stored in libraries on the computer can be re-used on a aided cable design systems also provide intelligent tools which number of different projects. It is therefore useful to create a master enable the designer to check their designs and produce bills of library of components for use on all projects undertaken. These material for a complete project. should not only be the graphical representation of the component CAD became popular in the 1960s to assist in the layout of but should also contain non-graphic information such as part num- microelectronic components on printed circuit boards and the de- ber and cost. sign of microchips. Since then it has been used by people as diverse Most CAD based cable design and management systems will as car designers and architects. There are a number of CAD systems allow the user to specify the type of equipment to be installed and available, each with their own special features and applications in the grid spacing on the floor. The system will automatically place specific areas. It is possible to exchange data between the various the components on the floor plan in an array. It is important to ensure systems SO that a variety of professionals can transmit drawings that the layout of components such as floor boxes is consistent with electronically and make the best use of the technology available to the floor tiles or the access to the under floor void. This is where the them. ability to exchange data with other consultants is important. The Some CAD systems available offer a range of applications which architect, build