Konftel Konftel 300IP, Установка и администрирование

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SEttINgS SEttINgS
MEDIA

Select
Settings
>
Media
.
The media settings affect how the audio is sent between the devices. The involved
devices perform a negotiation using SIP before a call is connected. All devices must
support the same media types, codecs and security settings.
Codec
Codecs are used to convert an analogue voice signal to a digitally encoded version and
vice versa. Codecs vary in the sound quality and the bandwidth required. Konftel 300IP
supports the most common codecs and each codec can be given a precedence depend-
ing of if you prefer high quality audio or low bandwidth use.
The priority can be set to from 4 (high) to 1 (low) or 0 (disabled)
G722
G.722 is an ITU-T standard codec that provides 7 kHz wideband
audio at a data rate within 64 kbit/s. It offers a significant
improvement in speech quality over older narrowband codecs
such as G.711, but requires a high quality network connection
between the devices.
G711 Alaw G.711 is an ITU-T standard codec that uses audio companding.
Companding algorithms reduce the dynamic range of an audio
signal. In analogue systems, this can increase the signal-to-noise
ratio achieved during transmission, and in the digital domain, it
can reduce the quantization error.
There are two main compression algorithms defined in the
standard, the µ-law algorithm (used in North America & Japan)
and A-law algorithm (used in Europe and the rest of the world).
G711 Ulaw See G711 µ-law above.
G729 G.729 is an ITU-T standard codec that operates at 8 kbit/s. It
is mostly used in VoIP applications with low bandwidth require-
ment.
On phone: MENu > SEttINgS > ADvANCED > (PIN) > MEDIA > CoDEC (5,2,4,1).
Security
The media in VoIP calls is usually sent using the RTP protocol ( Real-time Transport
Protocol ). RTP is a standardized packet format for delivering audio and video over the
Internet.
SRTP (
Secure Real-time Transport Protocol ) is an extension to RTP to provide encryp-
tion, message authentication and integrity for the audio and video streams.
All devices must support SRTP to establish a connection, and therefore there is pos -
sible to set SRTP as disabled, optional or mandatory.
SRTP
If set to disabled, the media is sent using RTP. Note that despite
this setting, Konftel 300IP will still use a secure channel if the
opposite device demands it.
If set to optional or mandatory, a padlock will be shown in the
right lower corner on the display. If the other devices support
SRTP, the padlock will be shown closed. If not it will be shown
open.
If set to mandatory, the call will not be connected if the other
devices do not support SRTP.
Secure signalling The SIP messages (signalling) and the SRTP cipher key are sent
on a different channel than the media and are not affected by
the RTP/SRTP setting. To ensure a secure connection, the signal-
ling must be secured using
tLS or SIPS , see page 20. Note that
the SIP transport setting must be set accordingly.
On phone: MENu > SEttINgS > ADvANCED > (PIN) > MEDIA > SECuRItY (5,2,4,4).