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Optimising voice quality for VoIP connections
Optimising voice quality for VoIP connections
You can make general and connection-specific settings to improve the voice quality for
VoIP telephony.
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Open the following Web page:
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 com-
pressed. 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:
G711 a law / G711 µ law
Excellent voice quality (comparable with ISDN). The necessary bandwidth is 64 kbit/s
per voice connection.
G726
Good voice quality (inferior to that with G711 but better than with G729).
Your phone supports G726 with a transmission rate of 32 kbit/s per voice connection.
G729
Average voice quality. The necessary bandwidth is less than 8 kbit/s per voice connec-
tion.
Both sides of a phone connection (caller/sender side and receiver side) 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 established.
Area:
Settings for Bandwidth
The settings in this area influence all VoIP connections (VoIP phone numbers).
Allow 1 VoIP call only
Generally speaking you can make two VoIP calls at the same time on your phone. If,
however, your DSL connection has a narrow bandwidth, there may be problems if two
VoIP calls are made at the same time. The data is no longer transferred properly (long
voice delay, data losses etc.).
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Activate the
Yes
phone connections being established.
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If you wish to permit two VoIP connections, activate the
Please note: If only one VoIP connection is permitted, the following VoIP network services are no
longer available:
– Call waiting
Call waiting is not displayed during a call via VoIP.
– External consultation call from a VoIP call
– Toggling and initiating a conference call via VoIP
Settings
option next to
Allow 1 VoIP call only
¢
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Telephony
Audio.
to prevent any further parallel VoIP
No
option.
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