Motorola D10 Service Manual page 49

BenQ Rev 1.0
♦
Digital Air Interface - The GSM phone will provide an entirely digital
link between the telephone and the base station, which is, in turn,
digitally linked into the switching subsystems and on into the PSTN.
♦ISDN Compatibility - ISDN is a digital communications standard that
many countries are committed to implementing. It is designed to carry
digital voice and data over existing copper telephone cables. The GSM
phone will be able to offer similar features to the ISDN telephone.
♦Security and Confidentiality – Telephone calls on analogue systems
can very easily be overheard by the use of a suitable radio receiver.
GSM offers vastly improved confidentiality because of the way in which
data is digitally encrypted and transmitted.
♦Better Call Quality - Co-channel interference, handover breaks, and
fading will be dealt with more effectively in the digital system. The call
quality is also enhanced by error correction, which reconstructs lost
information.
♦Efficiency - The GSM system will be able to use spectral resources
in a much more efficient way than previous analogue
Systems
In the figure below, the area bounded by bold lines represents the
total coverage area of a hypothetical system. This area is divided into
several cells, each containing a cell site (base station) operating on a
given set of channels which interfaces radiotele- phone subscribers to
the telephone switching system.
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