Following is a laundry list of current and future cellular technologies:
Circuit-switched network
The most widespread option for transmitting cellular data is over the circuit-switched network, which is the existing analog cellular network, technically known as the AMPS (Advanced Mobile Phone Services) network. The circuit-switched network is ideal for larger data transmissions, such as facsimiles, company files, contracts, billing documents, or data-intensive graphics and images. Availability: Currently available in all cellular markets.
Cellular Digital Packet Data
Developed by a consortium of seven of the largest cellular carriers as an overlay to the existing circuit-switched network, CDPD works by breaking data into small packets and routing them over idle channels of the existing cellular network. The CDPD system works best for transmitting short bursts of data, for point of sale, tracking, dispatch and messaging. CDPD and circuit-switched services are complementary technologies. Availability: Currently available in selected geographies; will become available in a wide range of markets next year.
Code Division Multiple Access
CDMA is a next-generation digital cellular standard that allows significant capacity increases (6-10) over the existing analog cellular network. It does this by appropriating a large, contiguous section of cellular bandwidth for all signals. This means conversations are converted into digital speech, assigned unique codes, and then spread or modulated across the entire CDMA band-converting a conversation into many packets of voice and digital data for transportation across the network. Availability: mid 1995.
Time Division Multiple Access
TDMA simultaneously converts existing analog voice channels into digital channels. Each digital channel is shared among three callers. Because the circuit-switched system supports only one call at a time, TDMA increases circuit-switched system capacity by a factor of three. Availability: Currently available in selected markets.
