The older technology of analog telecommunication is gradually being replaced by digital systems. Not only is digital communication faster, clearer, and more efficient (in terms of frequency use) than analog, but it also has the potential for data transmission services other than voice. According to mobilis, "Digital transmission has several basic advantages" including

Economies of bandwidth. Digitized signals can hop

invisibly between any number of free lines, minimizing line

overload. In a similar manner, several voice and/or data

transmissions can take place simultaneously on a single line.

Ease of integration. Digital technology enables a natural

integration with Personal Communication System (PCS)

devices.

Quality. Since voice is transmitted over distances in digital

form, its quality is easier to maintain over very long distances.

Privacy. Well encrypted digital transmission is almost

impossible to decode, an important consideration for a

wireless system.

Lower power, smaller device. Because of digital

modulation techniques, devices can use lower average

transmitter power thereby reducing the size and cost of the

unit.

Excellent future potential. Digital offers an appealing

potential for further bandwidth reductions with the inclusion

of Digital Signal Processors (DSPs) and better speech coders

(circuit elements that convert speech to blocks of digital code).

Digital wireless cellular systems which connect

seamlessly to ISDN are also being developed, with

some systems already available.

The distinction between cellular systems and PCS (Personal Communication Services) is analogous to the distinction between analog and digital. In most cases, the distinction is identical. Cellular systems are more or less analog systems that have existed for decades. PCS are relatively recent digital technologies that have yet to be implemented in most areas. The balance between the two will soon swing toward PCS, however, as the FCC (Federal Communications Commission) auctions have provided for only two cellular carriers per geographical area, competing with six PCS carriers. In general, the accepted cellular system has been the analog Advanced Mobile Phone System (AMPS). Compared to the newer digital PCS technologies, such as TDMA and CDMA, AMPS will quickly be outdated.