Installation guide

What is IP telephony? 28-2
Chapter 28: Understanding Wave IP Telephony
Wave Global Administrator Guide
What is IP telephony?
IP telephony, also known as voice over IP, allows you to make phone calls using segments of
your data network rather than the traditional Public Switched Telephone Network (PSTN). The
two different types of calls are transmitted over different networks, as shown in the following
diagram:
To transmit voice over the data network, a Digital Signal Processor (DSP), using a codec (a
signal compression-decompression algorithm), splits up the voice signals into small parts,
compresses them, and inserts them into data packets. The packets are addressed to the call
recipient (an IP address) and sent out over the data network. The packets are reassembled by a
DSP at the receiving end.
Using IP telephony, Wave users can:
• Call extensions on remote Wave sites over the data network (site-to-site IP calls)
• Save money on long distance calls by using a virtual tie-line to place calls through a
remote Wave system (sometimes called tandem call routing).
• Accommodate remote workers and small satellite offices with IP phones (telecommuters,
small branch offices)
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102
Wave ISM A
Wave ISM B
PSTN
IP
data
packets
data
packets
voice
packets
voice
packets
IP phone 101
DSP
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Release 2.0
September 2010