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New Zealand Phone Info |
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The telephone or phone is a
telecommunications device which is used to transmit and receive
sound (most commonly voice and speech) across distance. Most
telephones operate through transmission of electric signals over
a complex telephone network which allows almost any phone user
to communicate with almost any other.
Introduction
An elementary telephone system consists of three elements:
For each subscriber, the system must contain the equipment
necessary to convert sound to electrical signals and back. This
allows the subscriber to answer or initiate a call.
The system must contain a central switching facility which
interconnects all the subscribers.
Finally, the system requires wiring or other means to connect
the subscribers to the central switching facility.
There are three principal ways a subscriber may be connected to
the telephone network:
Historically, and still very commonly, by dedicated physical
wire connections run in overhead or underground cables;
By radio, as in a cordless, cellular, satellite or
radiotelephone and
By voice over internet protocol (VoIP) telephones, which use
broadband internet connections.
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