Integrated circuit

Populary called silicon chip,a miniaturzed electronic circuit produced on a single crystal or chip of a semiconduting meterial useually silicon.It may contain many thousands of components and yet thick .The IC is encapsulated within a plastic or ceremiv case,and linked via gold wires to metal pins with which it is connected to printed circuit board.
Integrated services Digital Network(ISDN) Internationally devoloed telecommunicatins system for sending signals in digital format along optical fibres or conventional metel cables .The system currently runs in the UK at 2Mb/s greatly increasing the amountof information that can be carried compared with analogue lines The first large scale use of ISDN began in japn 1988.The system forms the basus for the opertations of video phones and video conferencing.