Telephones go digital: Lower cost, higher performance and greater flexibility favor the digital approach over analog switching

It is only a matter of time before the largely analog telephone system becomes all-digital. One big reason is cost. Devices like microprocessors, memory, and logic are now no more expensive than analog devices. Another reason is performance. Digital switching networks are easier to maintain than analog; they have fewer components for higherreliabilitylevels, require less floor space, dissipate less power and are easier to install. In addition they can handle more traffic per equipment frame and provide uniform transmission capabilities, Yet a third big reason is versatility. When put into digital form, information from a variety of sources-video, audio, and facsimile-can be multiplexed and transmitted over conventional and coaxial cable, radio waves, and other media. Digital information can also be easily coded for privacy, a must for such modern telecommunications services as electronic funds transfer.