The growth in communications over the past 60 years has been phenomenal. The invention of the transistor in 1947 and the integrated circuit and laser in 1958 have paved the way to satellite communication systems. Most of the wire-line communication systems are being replaced by fiber-optic cables (providing extremely high bandwidth), which makes the transmission of a wide variety of information sources (voice, data, and video) possible. High-speed communication networks linking computers and the greater need for personal communication services are justthe beginning of the modern telecommunications era.