Prestige 2302 Support Notes
All contents copyright (c) 2005 ZyXEL Communications Corporation.
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International Telecommunication Union standard, it was designed from a telecommunications perspective. Both
standards have the same objective - to enable voice and multimedia convergence with IP protocols.
Can H.323 and SIP interoperate with each other?
In interoperability between the two, the industry is making slow but sure progress. Interoperability must first
happen between vendor implementations of the same protocol (SIP-to-SIP and H.323-to-H.323) and then
between protocols. Currently in order for SIP client to talk to H.323 client the ITSP must have a trunking
gateway act as a translator between the two protocols without the truncking gateway the two protocols are not
able to communicate to one another.
What is voice quality?
Voice quality is how well a person can hear the voice on the opposite end.
How are voice quality normally rated?
Voice quality is most commonly rated through a voice quality metric called the Mean Opinion Score (MOS)
which is recommendation by ITU-T. The MOS is a 5-point scale where 5 represent excellent voice quality and
1 represent bad voice quality.
What is codec?
Codec is an algorithm that converts analog signal into digital signal and vice versa. There are three codeec
types: waveform, source, and hybrid codec. Each consume different amount of bandwidth and provide different
voice quality.
What is the relationship between codec and VoIP?
VoIP is the general term to refer to the sending of digitized voice information in discrete packets over public
digital network (the Internet) where other data packets can be sent at the same time. A codec determines how
much bandwidth voice packets will use. To save bandwidth usage, you would use as little bandwidth as possible
at the cost of reduced voice quality.
What codec types does Prestige support?
The Prestige supports the following commonly used codecs.
•
G.729 voice codec
•
G.711u-law voice codec