Optimising Voice Quality For Voip Connections - Siemens Gigaset A580IP Manual

Web configurator – Setting the phone using a PC

Optimising voice quality for VoIP connections

You can make general and connection-specific settings to improve the voice qual-
ity for VoIP telephony.
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Open the following Web page: Settings
The voice quality for VoIP connections is mainly determined by the voice codec
used for transferring the data and the available bandwidth of your DSL connection.
In the case of the voice codec, the voice data is digitalised (coded/decoded) and
compressed. A "better" codec (better voice quality) means more data needs to be
transferred, i.e. perfect voice data transfer requires a DSL connection with a larger
bandwidth.
The following voice codecs are supported by your phone:
G.722 Excellent voice quality. The broadband speech codec G.722 works at the same bit
rate as G.711 (64 kbit/s per speech connection) but with a higher sampling rate. This
allows higher frequencies to be played back. The speech tone is therefore clearer
and better than for the other codecs (High Definition Sound Performance).
Gigaset S67H, S68H and SL37H handsets, for example, are HDSP-compatible.
G.711 a law / G.711 μ law
Excellent voice quality (comparable with ISDN). The necessary bandwidth is
64 kbit/s per voice connection.
G.726 Good voice quality (inferior to that with G.711 but better than with G.729).
Your phone supports G726 with a transmission rate of 32 kbit/s per voice
connection.
G.729 Average voice quality. The necessary bandwidth is less than or equal to 8 kbit/s per
voice connection.
Both parties involved in the telephone connection (caller/sender and receiver)
must use the same voice codec. The voice codec is negotiated between the sender
and the recipient when establishing a connection.
You can influence the voice quality by selecting (bearing in mind the bandwidth of
your DSL connection) the voice codecs your phone is to use, and specifying the
order in which the codecs are to be suggested when a VoIP connection is estab-
lished.
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Telephony Audio.