How does an IP telephone System work by JamesSteele


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									How does an
IP telephone
system work?
A guide to the basic workings of an
       IP telephone system

An IP (Internet Protocol) telephone
system is one which uses VoIP (Voice over
Internet Protocol) to make a call over the
internet rather than the traditional
analogue phone network.

An IP telephone system allows calls to be
made more cheaply than on a traditional
analogue phone network.

All IP telephone systems use codecs to
convert the analogue signal from the
microphone into a digital data signal
suitable to be sent over the internet.

At the speakers end the codec
compresses the data so less bandwidth is
needed to transmit it. Then at the
listeners end the codec decompresses
the data so it can be converted into
         Phone Lines

In a call over a traditional phone network
you basically take over the entire copper
line for the duration of your call.

By using your internet connection and a
technology called packet switching IP
telephone systems use much less of the
copper line’s capacity.
Calling Analogue Phones

As traditional analogue phones don’t
have the required codecs, how can IP
phone systems make calls to them?

In this case the phone service provider
handles the compression and
decompression turning the signal back to
analogue before it reaches the other end.
       Along the Way

∗ The call starts with the device being
  used to make the call – could be a VoIP
  handset or PC.
∗ It then goes to the company’s IP
  telephone system hub/switch.
∗ From there it it’s sent over the internet
  to the service provider’s VoIP server.
∗ The VoIP server then connects the call
  to its destination.
∗ If the recipient is using VoIP the
  process then happens again in reverse.

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